Spring续集

6.2、转发视图
SpringMVC中默认的转发视图是InternalResourceView SpringMVC中创建转发视图的情况：
当控制器方法中所设置的视图名称以"forward:"为前缀时，创建InternalResourceView视图，此时的视图名称不会被SpringMVC配置文件中所配置的视图解析器解析，而是会将前缀"forward:“去掉，剩余部 分作为最终路径通过转发的方式实现跳转
例如"forward:/”，“forward:/employee”

@RequestMapping("/testForward") public String testForward(){
return "forward:/testHello";
}
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注：
重定向视图在解析时，会先将redirect:前缀去掉，然后会判断剩余部分是否以/开头，若是则会自动拼接上下文路径
6.4、视图控制器view-controller
当控制器方法中，仅仅用来实现页面跳转，即只需要设置视图名称时，可以将处理器方法使用view- controller标签进行表示

<!--
path：设置处理的请求地址
view-name：设置请求地址所对应的视图名称
-->
<mvc:view-controller path="/testView" view-name="success"></mvc:view-controller>
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注：
当SpringMVC中设置任何一个view-controller时，其他控制器中的请求映射将全部失效，此时需  要在SpringMVC的核心配置文件中设置开启mvc注解驱动的标签：
<mvc:annotation-driven />
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7、RESTful

7.1、RESTful简介
REST：Representational State Transfer，表现层资源状态转移。
①资源
资源是一种看待服务器的方式，即，将服务器看作是由很多离散的资源组成。每个资源是服务器上一个 可命名的抽象概念。因为资源是一个抽象的概念，所以它不仅仅能代表服务器文件系统中的一个文件、 数据库中的一张表等等具体的东西，可以将资源设计的要多抽象有多抽象，只要想象力允许而且客户端 应用开发者能够理解。与面向对象设计类似，资源是以名词为核心来组织的，首先关注的是名词。一个 资源可以由一个或多个URI来标识。URI既是资源的名称，也是资源在Web上的地址。对某个资源感兴趣的客户端应用，可以通过资源的URI与其进行交互。
②资源的表述
资源的表述是一段对于资源在某个特定时刻的状态的描述。可以在客户端-服务器端之间转移（交
换）。资源的表述可以有多种格式，例如HTML/XML/JSON/纯文本/图片/视频/音频等等。资源的表述格式可以通过协商机制来确定。请求-响应方向的表述通常使用不同的格式。
③状态转移
状态转移说的是：在客户端和服务器端之间转移（transfer）代表资源状态的表述。通过转移和操作资源的表述，来间接实现操作资源的目的。
7.2、RESTful的实现
具体说，就是 HTTP 协议里面，四个表示操作方式的动词：GET、POST、PUT、DELETE。
它们分别对应四种基本操作：GET 用来获取资源，POST 用来新建资源，PUT 用来更新资源，DELETE 用来删除资源。
REST 风格提倡 URL 地址使用统一的风格设计，从前到后各个单词使用斜杠分开，不使用问号键值对方式携带请求参数，而是将要发送给服务器的数据作为 URL 地址的一部分，以保证整体风格的一致性。

7.3、HiddenHttpMethodFilter
由于浏览器只支持发送get和post方式的请求，那么该如何发送put和delete请求呢？
SpringMVC 提供了 HiddenHttpMethodFilter 帮助我们将 POST 请求转换为 DELETE 或 PUT 请求HiddenHttpMethodFilter 处 理 put 和 delete 请 求 的 条 件 ：
a>当前请求的请求方式必须为post b>当前请求必须传输请求参数_method
满足以上条件，HiddenHttpMethodFilter 过滤器就会将当前请求的请求方式转换为请求参数
_method的值，因此请求参数_method的值才是最终的请求方式
在web.xml中注册HiddenHttpMethodFilter

<filter>
<filter-name>HiddenHttpMethodFilter</filter-name>
<filter-class>org.springframework.web.filter.HiddenHttpMethodFilter</filter- class>
</filter>
<filter-mapping>
<filter-name>HiddenHttpMethodFilter</filter-name>
<url-pattern>/*

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注：
目前为止，SpringMVC中提供了两个过滤器：CharacterEncodingFilter和
HiddenHttpMethodFilter
在web.xml中注册时，必须先注册CharacterEncodingFilter，再注册HiddenHttpMethodFilter 原因：
在 CharacterEncodingFilter 中通过 request.setCharacterEncoding(encoding) 方法设置字符集的
request.setCharacterEncoding(encoding) 方法要求前面不能有任何获取请求参数的操作而 HiddenHttpMethodFilter 恰恰有一个获取请求方式的操作：

String paramValue = request.getParameter(this.methodParam);
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、RESTful案例

8.1、准备工作
和传统 CRUD 一样，实现对员工信息的增删改查。搭建环境
准备实体类

package com.softeem.mvc.bean;

public class Employee {

private Integer id; private String lastName;

private String email;
//1 male, 0 female private Integer gender;

public Integer getId() { 
return id;
}

public void setId(Integer id) { 
this.id = id;
}

public String getLastName() { 
return lastName;
}

public void setLastName(String lastName) { 
this.lastName = lastName;
}

public String getEmail() { 
return email;
}

public void setEmail(String email) { 
this.email = email;
}

public Integer getGender() { 
return gender;
}

public void setGender(Integer gender) { 
this.gender = gender;
}

public Employee(Integer id, String lastName, String email, Integer gender) {
super(); this.id = id;
this.lastName = lastName; this.email = email; this.gender = gender;
}

public Employee() {
}
}
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准备dao模拟数据

package com.softeem.mvc.dao;

import java.util.Collection; import java.util.HashMap; import java.util.Map;

import com.softeem.mvc.bean.Employee;
import org.springframework.stereotype.Repository;
@Repository
public class EmployeeDao {

private static Map<Integer, Employee> employees = null;

static{
employees = new HashMap<Integer, Employee>();

employees.put(1001, new Employee(1001, "E-AA", "aa@163.com", 1)); employees.put(1002, new Employee(1002, "E-BB", "bb@163.com", 1)); employees.put(1003, new Employee(1003, "E-CC", "cc@163.com", 0)); employees.put(1004, new Employee(1004, "E-DD", "dd@163.com", 0)); employees.put(1005, new Employee(1005, "E-EE", "ee@163.com", 1));
}

private static Integer initId = 1006;

public void save(Employee employee){ 
if(employee.getId() == null){
employee.setId(initId++);
}
employees.put(employee.getId(), employee);
}

public Collection<Employee> getAll(){ 
return employees.values();
}

public Employee get(Integer id){ 
return employees.get(id);
}

public void delete(Integer id){ 
employees.remove(id);
}
}
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8.2、功能清单

8.3、具体功能：访问首页
①配置view-controller

<mvc:view-controller path="/" view-name="index"/>
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②创建页面

<!DOCTYPE html>
<html lang="en" xmlns:th="http://www.thymeleaf.org">
<head>
<meta charset="UTF-8" >
<title>Title</title>
</head>
<body>
<h1>首页</h1>
<a th:href="@{/employee}">访问员工信息</a>
</body>
</html>
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8.4、具体功能：查询所有员工数据
①控制器方法

@RequestMapping(value = "/employee", method = RequestMethod.GET) public String getEmployeeList(Model model){
Collection<Employee> employeeList = employeeDao.getAll(); model.addAttribute("employeeList", employeeList);
return "employee_list";
}
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②创建employee_list.html

<!DOCTYPE html>
<html lang="en" xmlns:th="http://www.thymeleaf.org">
<head>
<meta charset="UTF-8">
<title>Employee Info</title>
<script type="text/javascript" th:src="@{/static/js/vue.js}"></script>
</head>
<body>


<table border="1" cellpadding="0" cellspacing="0" style="text-align: center;" id="dataTable">
<tr>
<th colspan="5">Employee Info</th>
</tr>
<tr>
<th>id</th>
<th>lastName</th>
<th>email</th>
<th>gender</th>
<th>options(<a th:href="@{/toAdd}">add</a>)</th>
</tr>
<tr th:each="employee : ${employeeList}">
<td th:text="${employee.id}"></td>
<td th:text="${employee.lastName}"></td>
<td th:text="${employee.email}"></td>
<td th:text="${employee.gender}"></td>
<td>
<a class="deleteA" @click="deleteEmployee" th:href="@{'/employee/'+${employee.id}}">delete</a>
<a th:href="@{'/employee/'+${employee.id}}">update</a>
</td>
</tr>
</table>
</body>
</html>
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8.5、具体功能：删除
①创建处理delete请求方式的表单

<!-- 作用：通过超链接控制表单的提交，将post请求转换为delete请求 -->
<form id="delete_form" method="post">
<!-- HiddenHttpMethodFilter要求：必须传输_method请求参数，并且值为最终的请求方式 -->
<input type="hidden" name="_method" value="delete"/>
</form>
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②删除超链接绑定点击事件

引入vue.js

<script type="text/javascript" th:src="@{/static/js/vue.js}"></script>
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删除超链接

<a class="deleteA" @click="deleteEmployee" th:href="@{'/employee/'+${employee.id}}">delete</a>
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通过vue处理点击事件

<script type="text/javascript"> var vue = new Vue({
el:"#dataTable", methods:{
//event表示当前事件
deleteEmployee:function (event) {
//通过id获取表单标签
var delete_form = document.getElementById("delete_form");
//将触发事件的超链接的href属性为表单的action属性赋值delete_form.action = event.target.href;
//提交表单delete_form.submit();
//阻止超链接的默认跳转行为event.preventDefault();
}
}
});
</script>
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③控制器方法

@RequestMapping(value = "/employee/{id}", method = RequestMethod.DELETE) public String deleteEmployee(@PathVariable("id") Integer id){
employeeDao.delete(id); return "redirect:/employee";
}
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8.6、具体功能：跳转到添加数据页面
①配置view-controller

<mvc:view-controller path="/toAdd" view-name="employee_add"></mvc:view- controller>
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②创建employee_add.html

<!DOCTYPE html>
<html lang="en" xmlns:th="http://www.thymeleaf.org">
<head>
<meta charset="UTF-8">
<title>Add Employee</title>
</head>
<body>
<form th:action="@{/employee}" method="post"> lastName:<input type="text" name="lastName"><br> email:<input type="text" name="email"><br> gender:<input type="radio" name="gender" value="1">male
<input type="radio" name="gender" value="0">female<br>
<input type="submit" value="add"><br>
</form>

</body>
</html>
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8.7、具体功能：执行保存
①控制器方法

@RequestMapping(value = "/employee", method = RequestMethod.POST) public String addEmployee(Employee employee){
employeeDao.save(employee); return "redirect:/employee";
}
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8.8、具体功能：跳转到更新数据页面
①修改超链接

<a th:href="@{'/employee/'+${employee.id}}">update</a>
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②控制器方法

@RequestMapping(value = "/employee/{id}", method = RequestMethod.GET) public String getEmployeeById(@PathVariable("id") Integer id, Model model){
Employee employee = employeeDao.get(id); model.addAttribute("employee", employee); return "employee_update";
}
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③创建employee_update.html

<!DOCTYPE html>
<html lang="en" xmlns:th="http://www.thymeleaf.org">
<head>
<meta charset="UTF-8">
<title>Update Employee</title>
</head>
<body>

<form th:action="@{/employee}" method="post">
<input type="hidden" name="_method" value="put">
<input type="hidden" name="id" th:value="${employee.id}">
lastName:<input type="text" name="lastName" th:value="${employee.lastName}">
<br>
email:<input type="text" name="email" th:value="${employee.email}"><br>
<!--
th:field="${employee.gender}"可用于单选框或复选框的回显
若单选框的value和employee.gender的值一致，则添加checked="checked"属性
-->
gender:<input type="radio" name="gender" value="1" th:field="${employee.gender}">male
<input type="radio" name="gender" value="0" th:field="${employee.gender}">female<br>
<input type="submit" value="update"><br>
</form>

</body>
</html>
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8.9、具体功能：执行更新
①控制器方法

@RequestMapping(value = "/employee", method = RequestMethod.PUT) public String updateEmployee(Employee employee){
employeeDao.save(employee); return "redirect:/employee";
}
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9、SpringMVC处理ajax请求

9.1、@RequestBody
@RequestBody可以获取请求体信息，使用@RequestBody注解标识控制器方法的形参，当前请求的请 求体就会为当前注解所标识的形参赋值

<!--此时必须使用post请求方式，因为get请求没有请求体-->
<form th:action="@{/test/RequestBody}" method="post">
用户名：<input type="text" name="username"><br>
密码：<input type="password" name="password"><br>
<input type="submit">
</form>
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@RequestMapping("/test/RequestBody")
public String testRequestBody(@RequestBody String requestBody){ 
System.out.println("requestBody:"+requestBody);
return "success";
}
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输出结果：
requestBody:username=admin&password=123456
9.2、@RequestBody获取json格式的请求参数
在使用了axios发送ajax请求之后，浏览器发送到服务器的请求参数有两种格式：
1、name=value&name=value…，此时的请求参数可以通过request.getParameter()获取，对应
SpringMVC中，可以直接通过控制器方法的形参获取此类请求参数
2、{key:value,key:value,…}，此时无法通过request.getParameter()获取，之前我们使用操作
json的相关jar包gson或jackson处理此类请求参数，可以将其转换为指定的实体类对象或map集 合。在SpringMVC中，直接使用@RequestBody注解标识控制器方法的形参即可将此类请求参数 转换为java对象
使用@RequestBody获取json格式的请求参数的条件：
1、导入jackson的依赖

<dependency>
<groupId>com.fasterxml.jackson.core</groupId>
<artifactId>jackson-databind</artifactId>
<version>2.12.1</version>
</dependency>
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2、SpringMVC的配置文件中设置开启mvc的注解驱动

<!--开启mvc的注解驱动-->
<mvc:annotation-driven />
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3、在控制器方法的形参位置，设置json格式的请求参数要转换成的java类型（实体类或map）的参数，并使用@RequestBody注解标识

<input type="button" value="测试@RequestBody获取json格式的请求参数" @click="testRequestBody()"><br>

<script type="text/javascript" th:src="@{/js/vue.js}"></script>
<script type="text/javascript" th:src="@{/js/axios.min.js}"></script>
<script type="text/javascript"> var vue = new Vue({
el:"#app", methods:{
testRequestBody(){ axios.post(
"/SpringMVC/test/RequestBody/json",
{username:"admin",password:"123456"}
).then(response=>{ console.log(response.data);
});
}
}
});
</script>
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//将json格式的数据转换为map集合@RequestMapping("/test/RequestBody/json")
public void testRequestBody(@RequestBody Map<String, Object> map, HttpServletResponse response) throws IOException {
System.out.println(map);
//{username=admin, password=123456} response.getWriter().print("hello,axios");
}
//将json格式的数据转换为实体类对象@RequestMapping("/test/RequestBody/json")
public void testRequestBody(@RequestBody User user, HttpServletResponse response) throws IOException {
System.out.println(user);
//User{id=null, username='admin', password='123456', age=null, gender='null'}
response.getWriter().print("hello,axios");
}
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9.3、@ResponseBody
@ResponseBody用于标识一个控制器方法，可以将该方法的返回值直接作为响应报文的响应体响应到浏览器

@RequestMapping("/testResponseBody") public String testResponseBody(){
//此时会跳转到逻辑视图success所对应的页面
return "success";
}

@RequestMapping("/testResponseBody") @ResponseBody
public String testResponseBody(){
//此时响应浏览器数据success return "success";
}
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9.4、@ResponseBody响应浏览器json数据
服务器处理ajax请求之后，大多数情况都需要向浏览器响应一个java对象，此时必须将java对象转换为json字符串才可以响应到浏览器，之前我们使用操作json数据的jar包gson或jackson将java对象转换为json字符串。在SpringMVC中，我们可以直接使用@ResponseBody注解实现此功能
@ResponseBody响应浏览器json数据的条件：
1、导入jackson的依赖

<dependency>
<groupId>com.fasterxml.jackson.core</groupId>
<artifactId>jackson-databind</artifactId>
<version>2.12.1</version>
</dependency>
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2、SpringMVC的配置文件中设置开启mvc的注解驱动

<!--开启mvc的注解驱动-->
<mvc:annotation-driven />
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3、使用@ResponseBody注解标识控制器方法，在方法中，将需要转换为json字符串并响应到浏览器的java对象作为控制器方法的返回值，此时SpringMVC就可以将此对象直接转换为json字符串并响应到 浏览器

<input type="button" value="测试@ResponseBody响应浏览器json格式的数据" @click="testResponseBody()"><br>

<script type="text/javascript" th:src="@{/js/vue.js}"></script>
<script type="text/javascript" th:src="@{/js/axios.min.js}"></script>
<script type="text/javascript"> var vue = new Vue({
el:"#app", methods:{
testResponseBody(){ 
axios.post("/SpringMVC/test/ResponseBody/json").then(response=>{
console.log(response.data);
});
}
}
});
</script>
//响应浏览器list集合@RequestMapping("/test/ResponseBody/json") @ResponseBody
public List<User> testResponseBody(){
User user1 = new User(1001,"admin1","123456",23,"男"); User user2 = new User(1002,"admin2","123456",23,"男"); User user3 = new User(1003,"admin3","123456",23,"男"); List<User> list = Arrays.asList(user1, user2, user3); return list;
}

//响应浏览器map集合@RequestMapping("/test/ResponseBody/json") @ResponseBody
public Map<String, Object> testResponseBody(){
User user1 = new User(1001,"admin1","123456",23,"男"); User user2 = new User(1002,"admin2","123456",23,"男"); User user3 = new User(1003,"admin3","123456",23,"男"); Map<String, Object> map = new HashMap<>(); map.put("1001", user1);
map.put("1002", user2);
map.put("1003", user3); return map;
}

//响应浏览器实体类对象@RequestMapping("/test/ResponseBody/json") @ResponseBody
public User testResponseBody(){ 
return user;
}
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9.5、@RestController注解
@RestController注解是springMVC提供的一个复合注解，标识在控制器的类上，就相当于为类添加了
@Controller注解，并且为其中的每个方法添加了@ResponseBody注解
10、文件上传和下载

10.1、文件下载
ResponseEntity用于控制器方法的返回值类型，该控制器方法的返回值就是响应到浏览器的响应报文，使用ResponseEntity实现下载文件的功能

@RequestMapping("/testDown")
public ResponseEntity<byte[]> testResponseEntity(HttpSession session) throws IOException {
//获取ServletContext对象
ServletContext servletContext = session.getServletContext();
//获取服务器中文件的真实路径
String realPath = servletContext.getRealPath("/static/img/1.jpg");
//创建输入流
InputStream is = new FileInputStream(realPath);
//创建字节数组
byte[] bytes = new byte[is.available()];
//将流读到字节数组中is.read(bytes);
//创建HttpHeaders对象设置响应头信息
MultiValueMap<String, String> headers = new HttpHeaders();
//设置要下载方式以及下载文件的名字
headers.add("Content-Disposition", "attachment;filename=1.jpg");
//设置响应状态码
HttpStatus statusCode = HttpStatus.OK;
//创建ResponseEntity对象
ResponseEntity<byte[]> responseEntity = new ResponseEntity<>(bytes, headers, statusCode);
//关闭输入流
is.close();
return responseEntity;
}
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10.2、文件上传
文件上传要求form表单的请求方式必须为post，并且添加属性enctype=“multipart/form-data”
SpringMVC中将上传的文件封装到MultipartFile对象中，通过此对象可以获取文件相关信息 上传步骤：
①添加依赖：

<!-- https://mvnrepository.com/artifact/commons-fileupload/commons-fileupload --
>
<dependency>
<groupId>commons-fileupload</groupId>
<artifactId>commons-fileupload</artifactId>
<version>1.3.1</version>
</dependency>
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②在SpringMVC的配置文件中添加配置：

<!--必须通过文件解析器的解析才能将文件转换为MultipartFile对象-->
<bean id="multipartResolver" class="org.springframework.web.multipart.commons.CommonsMultipartResolver">
</bean>
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③控制器方法：

@RequestMapping("/testUp")
public String testUp(MultipartFile photo, HttpSession session) throws IOException {
//获取上传的文件的文件名
String fileName = photo.getOriginalFilename();
//处理文件重名问题
String hzName = fileName.substring(fileName.lastIndexOf(".")); fileName = UUID.randomUUID().toString() + hzName;
//获取服务器中photo目录的路径
ServletContext servletContext = session.getServletContext(); String photoPath = servletContext.getRealPath("photo");
File file = new File(photoPath); if(!file.exists()){
file.mkdir();
}
String finalPath = photoPath + File.separator + fileName;
//实现上传功能
photo.transferTo(new File(finalPath)); return "success";
}
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11、拦截器

11.1、拦截器的配置
SpringMVC中的拦截器用于拦截控制器方法的执行
SpringMVC中的拦截器需要实现HandlerInterceptor
SpringMVC的拦截器必须在SpringMVC的配置文件中进行配置：

<bean class="com.softeem.interceptor.FirstInterceptor"></bean>
<ref bean="firstInterceptor"></ref>
<!-- 以上两种配置方式都是对DispatcherServlet所处理的所有的请求进行拦截 -->
<mvc:interceptor>
<mvc:mapping path="/**"/>
<mvc:exclude-mapping path="/testRequestEntity"/>
<ref bean="firstInterceptor"></ref>
</mvc:interceptor>
<!--
以上配置方式可以通过ref或bean标签设置拦截器，通过mvc:mapping设置需要拦截的请求，通过
mvc:exclude-mapping设置需要排除的请求，即不需要拦截的请求
-->
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11.2、拦截器的三个抽象方法
SpringMVC中的拦截器有三个抽象方法：
preHandle：控制器方法执行之前执行preHandle()，其boolean类型的返回值表示是否拦截或放行，返 回true为放行，即调用控制器方法；返回false表示拦截，即不调用控制器方法
postHandle： 控 制 器 方 法 执 行 之 后 执 行 postHandle() afterCompletion：处理完视图和模型数据，渲染视图完毕之后执行afterCompletion()
11.3、多个拦截器的执行顺序

①若每个拦截器的preHandle()都返回true
此时多个拦截器的执行顺序和拦截器在SpringMVC的配置文件的配置顺序有关：
preHandle()会按照配置的顺序执行，而postHandle()和afterCompletion()会按照配置的反序执行
②若某个拦截器的preHandle()返回了false
preHandle()返回false和它之前的拦截器的preHandle()都会执行，postHandle()都不执行，返回false
的拦截器之前的拦截器的afterCompletion()会执行
12、异常处理器

12.1、基于配置的异常处理
SpringMVC提供了一个处理控制器方法执行过程中所出现的异常的接口：HandlerExceptionResolver
HandlerExceptionResolver接口的实现类有：DefaultHandlerExceptionResolver和SimpleMappingExceptionResolver
SpringMVC提供了自定义的异常处理器SimpleMappingExceptionResolver，使用方式：

<bean class="org.springframework.web.servlet.handler.SimpleMappingExceptionResolver">
<property name="exceptionMappings">
<props>
<!--
properties的键表示处理器方法执行过程中出现的异常
properties的值表示若出现指定异常时，设置一个新的视图名称，跳转到指定页面
-->
<prop key="java.lang.ArithmeticException">error</prop>
</props>
</property>
<!--
exceptionAttribute属性设置一个属性名，将出现的异常信息在请求域中进行共享
-->
<property name="exceptionAttribute" value="ex"></property>
</bean>
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12.2、基于注解的异常处理

//@ControllerAdvice将当前类标识为异常处理的组件@ControllerAdvice
public class ExceptionController {

//@ExceptionHandler用于设置所标识方法处理的异常@ExceptionHandler(ArithmeticException.class)
//ex表示当前请求处理中出现的异常对象
public String handleArithmeticException(Exception ex, Model model){ 
model.addAttribute("ex", ex);
return "error";
}

}
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13、注解配置SpringMVC
使用配置类和注解代替web.xml和SpringMVC配置文件的功能
13.1、创建初始化类，代替web.xml
在Servlet3.0环境中，容器会在类路径中查找实现javax.servlet.ServletContainerInitializer接口的类， 如果找到的话就用它来配置Servlet容器。 Spring提供了这个接口的实现，名为
SpringServletContainerInitializer，这个类反过来又会查找实现WebApplicationInitializer的类并将配 置的任务交给它们来完成。Spring3.2引入了一个便利的WebApplicationInitializer基础实现，名为AbstractAnnotationConfigDispatcherServletInitializer，当我们的类扩展了
AbstractAnnotationConfigDispatcherServletInitializer并将其部署到Servlet3.0容器的时候，容器会自动发现它，并用它来配置Servlet上下文。

public class WebInit extends AbstractAnnotationConfigDispatcherServletInitializer {

/**
*指定spring的配置类
*@return
*/ @Override
protected Class<?>[] getRootConfigClasses() { 
return new Class[]{SpringConfig.class};
}


/**
*指定SpringMVC的配置类
*@return
*/ @Override
protected Class<?>[] getServletConfigClasses() { 
return new Class[]{WebConfig.class};
}


/**
*指定DispatcherServlet的映射规则，即url-pattern
*@return
*/ @Override
protected String[] getServletMappings() { 
return new String[]{"/"};
}


/**
*添加过滤器
*@return
*/ @Override
protected Filter[] getServletFilters() {
CharacterEncodingFilter encodingFilter = new CharacterEncodingFilter(); encodingFilter.setEncoding("UTF-8"); encodingFilter.setForceRequestEncoding(true);
HiddenHttpMethodFilter hiddenHttpMethodFilter = new HiddenHttpMethodFilter();
return new Filter[]{encodingFilter, hiddenHttpMethodFilter};
}
}

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13.2、创建SpringConfig配置类，代替spring的配置文件

@Configuration
public class SpringConfig {
//ssm整合之后，spring的配置信息写在此类中
}
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13.3、创建WebConfig配置类，代替SpringMVC的配置文件

@Configuration
//扫描组件@ComponentScan("com.softeem.mvc.controller")
//开启MVC注解驱动@EnableWebMvc
public class WebConfig implements WebMvcConfigurer {

//使用默认的servlet处理静态资源@Override
public void configureDefaultServletHandling(DefaultServletHandlerConfigurer configurer) {
configurer.enable();
}

//配置文件上传解析器@Bean
public CommonsMultipartResolver multipartResolver(){ 
return new CommonsMultipartResolver();
}

//配置拦截器@Override
public void addInterceptors(InterceptorRegistry registry) { 
FirstInterceptor firstInterceptor = new FirstInterceptor(); registry.addInterceptor(firstInterceptor).addPathPatterns("/**");
}

//配置视图控制
/*@Override
public void addViewControllers(ViewControllerRegistry registry) { 
registry.addViewController("/").setViewName("index");
}*/

//配置异常映射
/*@Override public void
configureHandlerExceptionResolvers(List resolvers) { 
SimpleMappingExceptionResolver exceptionResolver = new
SimpleMappingExceptionResolver(); Properties prop = new Properties();
prop.setProperty("java.lang.ArithmeticException", "error");
//设置异常映射exceptionResolver.setExceptionMappings(prop);
//设置共享异常信息的键exceptionResolver.setExceptionAttribute("ex"); resolvers.add(exceptionResolver);
}*/

//配置生成模板解析器@Bean
public ITemplateResolver templateResolver() { 
WebApplicationContext webApplicationContext =
ContextLoader.getCurrentWebApplicationContext();
// ServletContextTemplateResolver需要一个ServletContext作为构造参数，可通过
WebApplicationContext 的方法获得
ServletContextTemplateResolver templateResolver = new ServletContextTemplateResolver(
webApplicationContext.getServletContext()); templateResolver.setPrefix("/WEB-INF/templates/"); templateResolver.setSuffix(".html"); templateResolver.setCharacterEncoding("UTF-8"); templateResolver.setTemplateMode(TemplateMode.HTML); return templateResolver;
}

//生成模板引擎并为模板引擎注入模板解析器@Bean
public SpringTemplateEngine templateEngine(ITemplateResolver templateResolver) {
SpringTemplateEngine templateEngine = new SpringTemplateEngine(); templateEngine.setTemplateResolver(templateResolver);
return templateEngine;
}

//生成视图解析器并未解析器注入模板引擎@Bean
public ViewResolver viewResolver(SpringTemplateEngine templateEngine) { 
ThymeleafViewResolver viewResolver = new ThymeleafViewResolver(); viewResolver.setCharacterEncoding("UTF-8"); viewResolver.setTemplateEngine(templateEngine);
return viewResolver;
}



}

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13.4、测试功能

@RequestMapping("/") public String index(){
return "index";
}
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14、SpringMVC执行流程

14.1、SpringMVC常用组件
DispatcherServlet：前端控制器，不需要工程师开发，由框架提供
作用：统一处理请求和响应，整个流程控制的中心，由它调用其它组件处理用户的请求
HandlerMapping：处理器映射器，不需要工程师开发，由框架提供
作用：根据请求的url、method等信息查找Handler，即控制器方法
Handler：处理器，需要工程师开发
作用：在DispatcherServlet的控制下Handler对具体的用户请求进行处理
HandlerAdapter：处理器适配器，不需要工程师开发，由框架提供 作用：通过HandlerAdapter对处理器（控制器方法）进行执行
ViewResolver：视图解析器，不需要工程师开发，由框架提供
作用：进行视图解析，得到相应的视图，例如：ThymeleafView、InternalResourceView、
RedirectView
View：视图
作用：将模型数据通过页面展示给用户

14.2、DispatcherServlet初始化过程
DispatcherServlet 本质上是一个 Servlet，所以天然的遵循 Servlet 的生命周期。所以宏观上是 Servlet
生命周期来进行调度。

①初始化WebApplicationContext
所在类：org.springframework.web.servlet.FrameworkServlet

protected WebApplicationContext initWebApplicationContext() { 
WebApplicationContext rootContext =

WebApplicationContextUtils.getWebApplicationContext(getServletContext()); WebApplicationContext wac = null;
if (this.webApplicationContext != null) {
// A context instance was injected at construction time -> use it wac = this.webApplicationContext;
if (wac instanceof ConfigurableWebApplicationContext) { 
ConfigurableWebApplicationContext cwac =
(ConfigurableWebApplicationContext) wac;
if (!cwac.isActive()) {
// The context has not yet been refreshed -> provide services

such as


id, etc



parent -> set


parent



// setting the parent context, setting the application context


if (cwac.getParent() == null) {
// The context instance was injected without an explicit


// the root application context (if any; may be null) as the


cwac.setParent(rootContext);

}
configureAndRefreshWebApplicationContext(cwac);
}
}
}
if (wac == null) {
// No context instance was injected at construction time -> see if one
// has been registered in the servlet context. If one exists, it is

assumed





}



// that the parent context (if any) has already been set and that the
// user has performed any initialization such as setting the context id wac = findWebApplicationContext();

if (wac == null) {
// No context instance is defined for this servlet -> create a local one
// 创建WebApplicationContext
wac = createWebApplicationContext(rootContext);
}


if (!this.refreshEventReceived) {
// Either the context is not a ConfigurableApplicationContext with

refresh



// support or the context injected at construction time had already been
// refreshed -> trigger initial onRefresh manually here. synchronized (this.onRefreshMonitor) {
// 刷新WebApplicationContext
onRefresh(wac);

}
}

if (this.publishContext) {
// Publish the context as a servlet context attribute.
// 将IOC容器在应用域共享
String attrName = getServletContextAttributeName(); getServletContext().setAttribute(attrName, wac);
}

return wac;
}

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②创建WebApplicationContext
所在类：org.springframework.web.servlet.FrameworkServlet

protected WebApplicationContext createWebApplicationContext(@Nullable ApplicationContext parent) {
Class<?> contextClass = getContextClass();
if (!ConfigurableWebApplicationContext.class.isAssignableFrom(contextClass))
{
throw new ApplicationContextException(
"Fatal initialization error in servlet with name '" + getServletName() +
"': custom WebApplicationContext class [" + contextClass.getName() + "] is not of type ConfigurableWebApplicationContext");
}
// 通过反射创建 IOC 容器对象
ConfigurableWebApplicationContext wac = (ConfigurableWebApplicationContext)
BeanUtils.instantiateClass(contextClass);

wac.setEnvironment(getEnvironment());
// 设置父容器
wac.setParent(parent);
String configLocation = getContextConfigLocation(); if (configLocation != null) {
wac.setConfigLocation(configLocation);
}
configureAndRefreshWebApplicationContext(wac);

return wac;
}
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③DispatcherServlet初始化策略
FrameworkServlet创建WebApplicationContext后，刷新容器，调用onRefresh(wac)，此方法在DispatcherServlet中进行了重写，调用了initStrategies(context)方法，初始化策略，即初始化
DispatcherServlet的各个组件
所在类：org.springframework.web.servlet.DispatcherServlet

protected void initStrategies(ApplicationContext context) { 
initMultipartResolver(context); initLocaleResolver(context); initThemeResolver(context); initHandlerMappings(context); initHandlerAdapters(context); initHandlerExceptionResolvers(context); initRequestToViewNameTranslator(context); initViewResolvers(context); initFlashMapManager(context);
}
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14.3、DispatcherServlet调用组件处理请求
①processRequest()
FrameworkServlet重写HttpServlet中的service()和doXxx()，这些方法中调用了processRequest(request, response)
所在类：org.springframework.web.servlet.FrameworkServlet

protected final void processRequest(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {

long startTime = System.currentTimeMillis(); Throwable failureCause = null;

LocaleContext previousLocaleContext = LocaleContextHolder.getLocaleContext();
LocaleContext localeContext = buildLocaleContext(request);

RequestAttributes previousAttributes = RequestContextHolder.getRequestAttributes();
ServletRequestAttributes requestAttributes = buildRequestAttributes(request, response, previousAttributes);

WebAsyncManager asyncManager = WebAsyncUtils.getAsyncManager(request); asyncManager.registerCallableInterceptor(FrameworkServlet.class.getName(),
new RequestBindingInterceptor());

initContextHolders(request, localeContext, requestAttributes);

try {
// 执行服务，doService()是一个抽象方法，在DispatcherServlet中进行了重写
doService(request, response);
}
catch (ServletException | IOException ex) { 
failureCause = ex;
throw ex;
}
catch (Throwable ex) { 
failureCause = ex;
throw new NestedServletException("Request processing failed", ex);
}

finally {
resetContextHolders(request, previousLocaleContext, previousAttributes); if (requestAttributes != null) {
requestAttributes.requestCompleted();
}
logResult(request, response, failureCause, asyncManager); publishRequestHandledEvent(request, response, startTime, failureCause);
}
}
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②doService()
所在类：org.springframework.web.servlet.DispatcherServlet

@Override
protected void doService(HttpServletRequest request, HttpServletResponse response) throws Exception {
logRequest(request);


// Keep a snapshot of the request attributes in case of an include,
// to be able to restore the original attributes after the include. Map attributesSnapshot = null;
if (WebUtils.isIncludeRequest(request)) { 
attributesSnapshot = new HashMap<>();
Enumeration<?> attrNames = request.getAttributeNames(); while (attrNames.hasMoreElements()) {
String attrName = (String) attrNames.nextElement(); if (this.cleanupAfterInclude ||
attrName.startsWith(DEFAULT_STRATEGIES_PREFIX)) {
attributesSnapshot.put(attrName, request.getAttribute(attrName));
}
}
}

// Make framework objects available to handlers and view objects. request.setAttribute(WEB_APPLICATION_CONTEXT_ATTRIBUTE,
getWebApplicationContext()); request.setAttribute(LOCALE_RESOLVER_ATTRIBUTE, this.localeResolver); request.setAttribute(THEME_RESOLVER_ATTRIBUTE, this.themeResolver); request.setAttribute(THEME_SOURCE_ATTRIBUTE, getThemeSource());

if (this.flashMapManager != null) {
FlashMap inputFlashMap = this.flashMapManager.retrieveAndUpdate(request, response);
if (inputFlashMap != null) { 
request.setAttribute(INPUT_FLASH_MAP_ATTRIBUTE,
Collections.unmodifiableMap(inputFlashMap));
}
request.setAttribute(OUTPUT_FLASH_MAP_ATTRIBUTE, new FlashMap()); request.setAttribute(FLASH_MAP_MANAGER_ATTRIBUTE, this.flashMapManager);
}


RequestPath requestPath = null; if (this.parseRequestPath &&
!ServletRequestPathUtils.hasParsedRequestPath(request)) { 
requestPath = ServletRequestPathUtils.parseAndCache(request);
}


try {
// 处理请求和响应
doDispatch(request, response);
}
finally { 
if
(!WebAsyncUtils.getAsyncManager(request).isConcurrentHandlingStarted()) {
// Restore the original attribute snapshot, in case of an include. if (attributesSnapshot != null) {
restoreAttributesAfterInclude(request, attributesSnapshot);
}
}
if (requestPath != null) { ServletRequestPathUtils.clearParsedRequestPath(request);
}
}
}
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③doDispatch()
所在类：org.springframework.web.servlet.DispatcherServlet

protected void doDispatch(HttpServletRequest request, HttpServletResponse response) throws Exception {
HttpServletRequest processedRequest = request; HandlerExecutionChain mappedHandler = null; boolean multipartRequestParsed = false;

WebAsyncManager asyncManager = WebAsyncUtils.getAsyncManager(request);


try {
ModelAndView mv = null;
Exception dispatchException = null;


try {
processedRequest = checkMultipart(request); multipartRequestParsed = (processedRequest != request);

// Determine handler for the current request.
/*
mappedHandler：调用链
包含handler、interceptorList、interceptorIndex handler：浏览器发送的请求所匹配的控制器方法
interceptorList：处理控制器方法的所有拦截器集合
interceptorIndex：拦截器索引，控制拦截器afterCompletion()的执行
*/
mappedHandler = getHandler(processedRequest); if (mappedHandler == null) {
noHandlerFound(processedRequest, response); return;
}


// Determine handler adapter for the current request.
//  通过控制器方法创建相应的处理器适配器，调用所对应的控制器方法
HandlerAdapter ha = getHandlerAdapter(mappedHandler.getHandler());


// Process last-modified header, if supported by the handler. String method = request.getMethod();
boolean isGet = "GET".equals(method); if (isGet || "HEAD".equals(method)) {
long lastModified = ha.getLastModified(request, mappedHandler.getHandler());
if (new ServletWebRequest(request, response).checkNotModified(lastModified) && isGet) {
return;
}
}

// 调用拦截器的preHandle()
if (!mappedHandler.applyPreHandle(processedRequest, response)) { 
return;
}
// Actually invoke the handler.
// 由处理器适配器调用具体的控制器方法，最终获得ModelAndView对象
mv = ha.handle(processedRequest, response, mappedHandler.getHandler());

if (asyncManager.isConcurrentHandlingStarted()) { 
return;
}

applyDefaultViewName(processedRequest, mv);
// 调 用 拦 截 器 的 postHandle() mappedHandler.applyPostHandle(processedRequest, response, mv);
}
catch (Exception ex) { 
dispatchException = ex;





well,

}
catch (Throwable err) {
// As of 4.3, we're processing Errors thrown from handler methods as


// making them available for @ExceptionHandler methods and other

scenarios.
dispatchException = new NestedServletException("Handler dispatch
failed", err);
}
// 后续处理：处理模型数据和渲染视图
processDispatchResult(processedRequest, response, mappedHandler, mv, dispatchException);
}
catch (Exception ex) {
triggerAfterCompletion(processedRequest, response, mappedHandler, ex);
}
catch (Throwable err) {
triggerAfterCompletion(processedRequest, response, mappedHandler,
new NestedServletException("Handler processing
failed", err));
}
finally {
if (asyncManager.isConcurrentHandlingStarted()) {
// Instead of postHandle and afterCompletion if (mappedHandler != null) {

mappedHandler.applyAfterConcurrentHandlingStarted(processedRequest, response);
}
}
else {
// Clean up any resources used by a multipart request. if (multipartRequestParsed) {
cleanupMultipart(processedRequest);
}
}
}
}
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④processDispatchResult()

private void processDispatchResult(HttpServletRequest request, HttpServletResponse response,@Nullable HandlerExecutionChain mappedHandler, @Nullable ModelAndView mv,
@Nullable Exception exception) throws
Exception {


boolean errorView = false;


if (exception != null) {
if (exception instanceof ModelAndViewDefiningException) { 
logger.debug("ModelAndViewDefiningException encountered",

exception);


}


mv = ((ModelAndViewDefiningException) exception).getModelAndView();




: null);

else {
Object handler = (mappedHandler != null ? mappedHandler.getHandler()


mv = processHandlerException(request, response, handler, exception); errorView = (mv != null);

}
}

// Did the handler return a view to render? if (mv != null && !mv.wasCleared()) {
// 处理模型数据和渲染视图
render(mv, request, response); if (errorView) {
WebUtils.clearErrorRequestAttributes(request);
}
}
else {
if (logger.isTraceEnabled()) {
logger.trace("No view rendering, null ModelAndView returned.");
}
}

if (WebAsyncUtils.getAsyncManager(request).isConcurrentHandlingStarted()) {
// Concurrent handling started during a forward return;
}


if (mappedHandler != null) {
// Exception (if any) is already handled..
// 调 用 拦 截 器 的 afterCompletion() mappedHandler.triggerAfterCompletion(request, response, null);
}
}
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14.4、SpringMVC的执行流程
1)用户向服务器发送请求，请求被SpringMVC 前端控制器 DispatcherServlet捕获。
2)DispatcherServlet对请求URL进行解析，得到请求资源标识符（URI），判断请求URI对应的映射：
a)不存在
i.再判断是否配置了mvc:default-servlet-handler
ii.如果没配置，则控制台报映射查找不到，客户端展示404错误


iii.如果有配置，则访问目标资源（一般为静态资源，如：JS,CSS,HTML），找不到客户端也会展示404 错误


b)存在则执行下面的流程
3)根据该URI，调用HandlerMapping获得该Handler配置的所有相关的对象（包括Handler对象以及
Handler对象对应的拦截器），最后以HandlerExecutionChain执行链对象的形式返回。
4)DispatcherServlet 根据获得的Handler，选择一个合适的HandlerAdapter。
5)如果成功获得HandlerAdapter，此时将开始执行拦截器的preHandler(…)方法【正向】
6)提取Request中的模型数据，填充Handler入参，开始执行Handler（Controller)方法，处理请求。在填充Handler的入参过程中，根据你的配置，Spring将帮你做一些额外的工作：
a)HttpMessageConveter： 将请求消息（如Json、xml等数据）转换成一个对象，将对象转换为指定的响应信息
b)数据转换：对请求消息进行数据转换。如String转换成Integer、Double等
c)数据格式化：对请求消息进行数据格式化。 如将字符串转换成格式化数字或格式化日期等
d)数据验证： 验证数据的有效性（长度、格式等），验证结果存储到BindingResult或Error中
7)Handler执行完成后，向DispatcherServlet 返回一个ModelAndView对象。
8)此时将开始执行拦截器的postHandle(…)方法【逆向】。
9)根据返回的ModelAndView（此时会判断是否存在异常：如果存在异常，则执行
HandlerExceptionResolver进行异常处理）选择一个适合的ViewResolver进行视图解析，根据Model
和View，来渲染视图。
10)渲染视图完毕执行拦截器的afterCompletion(…)方法【逆向】。
11)将渲染结果返回给客户端。

四、SSM整合
4.1、ContextLoaderListener

Spring提供了监听器ContextLoaderListener，实现ServletContextListener接口，可监听
ServletContext的状态，在web服务器的启动，读取Spring的配置文件，创建Spring的IOC容器。web
应用中必须在web.xml中配置

<listener>
<!--
配置Spring的监听器，在服务器启动时加载Spring的配置文件     Spring配置文件默认位置和名称：/WEB-INF/applicationContext.xml 可通过上下文参数自定义Spring配置文件的位置和名称
-->
<listener- class>org.springframework.web.context.ContextLoaderListener</listener-class>
</listener>

<!--自定义Spring配置文件的位置和名称-->
<context-param>
<param-name>contextConfigLocation</param-name>
<param-value>classpath:spring.xml</param-value>
</context-param>
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4.2、准备工作

①创建Maven Module
②导入依赖

<packaging>war</packaging>

<properties>
<spring.version>5.3.1</spring.version>
</properties>

<dependencies>
<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-context</artifactId>
<version>${spring.version}</version>
</dependency>
<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-beans</artifactId>
<version>${spring.version}</version>
</dependency>
<!--springmvc-->
<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-web</artifactId>
<version>${spring.version}</version>
</dependency>
<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-webmvc</artifactId>
<version>${spring.version}</version>
</dependency>
<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-jdbc</artifactId>
<version>${spring.version}</version>
</dependency>
<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-aspects</artifactId>
<version>${spring.version}</version>
</dependency>
<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-test</artifactId>
<version>${spring.version}</version>
</dependency>
<!-- Mybatis核心 -->
<dependency>
<groupId>org.mybatis</groupId>
<artifactId>mybatis</artifactId>
<version>3.5.7</version>
</dependency>
<!--mybatis和spring的整合包-->
<dependency>
<groupId>org.mybatis</groupId>
<artifactId>mybatis-spring</artifactId>
<version>2.0.6</version>
</dependency>
<!-- 连接池 -->
<dependency>
<groupId>com.alibaba</groupId>
<artifactId>druid</artifactId>
<version>1.0.9</version>
</dependency>
<!-- junit测试 -->
<dependency>
<groupId>junit</groupId>
<artifactId>junit</artifactId>
<version>4.12</version>
<scope>test</scope>
</dependency>
<!-- MySQL驱动 -->
<dependency>
<groupId>mysql</groupId>
<artifactId>mysql-connector-java</artifactId>
<version>8.0.16</version>
</dependency>
<!-- log4j日志 -->
<dependency>
<groupId>log4j</groupId>
<artifactId>log4j</artifactId>
<version>1.2.17</version>
</dependency>
<!-- https://mvnrepository.com/artifact/com.github.pagehelper/pagehelper -->
<dependency>
<groupId>com.github.pagehelper</groupId>
<artifactId>pagehelper</artifactId>
<version>5.2.0</version>
</dependency>
<!-- 日志 -->
<dependency>
<groupId>ch.qos.logback</groupId>
<artifactId>logback-classic</artifactId>
<version>1.2.3</version>
</dependency>
<!-- ServletAPI -->
<dependency>
<groupId>javax.servlet</groupId>
<artifactId>javax.servlet-api</artifactId>
<version>3.1.0</version>
<scope>provided</scope>
</dependency>
<dependency>
<groupId>com.fasterxml.jackson.core</groupId>
<artifactId>jackson-databind</artifactId>
<version>2.12.1</version>
</dependency>
<dependency>
<groupId>commons-fileupload</groupId>
<artifactId>commons-fileupload</artifactId>
<version>1.3.1</version>
</dependency>
<!-- Spring5和Thymeleaf整合包 -->
<dependency>
<groupId>org.thymeleaf</groupId>
<artifactId>thymeleaf-spring5</artifactId>
<version>3.0.12.RELEASE</version>
</dependency>
</dependencies>
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③创建表

CREATE TABLE `t_emp` (
`emp_id` int(11) NOT NULL AUTO_INCREMENT,
`emp_name` varchar(20) DEFAULT NULL,
`age` int(11) DEFAULT NULL,
`sex` char(1) DEFAULT NULL,
`email` varchar(50) DEFAULT NULL, PRIMARY KEY (`emp_id`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8
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4.3、配置web.xml

<!-- 配置Spring的编码过滤器 -->
<filter>
<filter-name>CharacterEncodingFilter</filter-name>
<filter- class>org.springframework.web.filter.CharacterEncodingFilter</filter-class>
<init-param>
<param-name>encoding</param-name>
<param-value>UTF-8</param-value>
</init-param>
<init-param>
<param-name>forceEncoding</param-name>
<param-value>true</param-value>
</init-param>
</filter>
<filter-mapping>
<filter-name>CharacterEncodingFilter</filter-name>
<url-pattern>/*




HiddenHttpMethodFilter
org.springframework.web.filter.HiddenHttpMethodFilter


HiddenHttpMethodFilter
/*




DispatcherServlet
org.springframework.web.servlet.DispatcherServlet


contextConfigLocation
classpath:SpringMVC.xml

1


DispatcherServlet
/




contextConfigLocation
classpath:Spring.xml




org.springframework.web.context.ContextLoaderListener

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4.4、创建SpringMVC的配置文件并配置

<!--扫描组件-->
<context:component-scan base-package="com.softeem.ssm.controller">
</context:component-scan>

<!--配置视图解析器-->
<bean id="viewResolver" class="org.thymeleaf.spring5.view.ThymeleafViewResolver">
<property name="order" value="1"/>
<property name="characterEncoding" value="UTF-8"/>
<property name="templateEngine">
<bean class="org.thymeleaf.spring5.SpringTemplateEngine">
<property name="templateResolver">
<bean class="org.thymeleaf.spring5.templateresolver.SpringResourceTemplateResolver">
<!-- 视图前缀 -->
<property name="prefix" value="/WEB-INF/templates/"/>
<!-- 视图后缀 -->
<property name="suffix" value=".html"/>
<property name="templateMode" value="HTML5"/>
<property name="characterEncoding" value="UTF-8" />
</bean>
</property>
</bean>
</property>
</bean>

<!-- 配置访问首页的视图控制 -->
<mvc:view-controller path="/" view-name="index"></mvc:view-controller>

<!-- 配置默认的servlet处理静态资源 -->
<mvc:default-servlet-handler />

<!-- 开启MVC的注解驱动 -->
<mvc:annotation-driven />
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4.5、搭建MyBatis环境

①创建属性文件jdbc.properties

jdbc.user=root jdbc.password=123456
jdbc.url=jdbc:mysql://localhost:3306/ssm?serverTimezone=UTC jdbc.driver=com.mysql.cj.jdbc.Driver
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②创建MyBatis的核心配置文件mybatis-config.xml

<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE configuration
PUBLIC "-//mybatis.org//DTD Config 3.0//EN" "http://mybatis.org/dtd/mybatis-3-config.dtd">

<configuration>


<settings>
<!--将下划线映射为驼峰-->
<setting name="mapUnderscoreToCamelCase" value="true"/>
</settings>

<plugins>
<!--配置分页插件-->
<plugin interceptor="com.github.pagehelper.PageInterceptor"></plugin>
</plugins>

</configuration>
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③创建Mapper接口和映射文件

public interface EmployeeMapper { 
List<Employee> getEmployeeList();
}
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<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE mapper
PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN" "http://mybatis.org/dtd/mybatis-3-mapper.dtd">
<mapper namespace="com.softeem.ssm.mapper.EmployeeMapper">

<select id="getEmployeeList" resultType="Employee"> select * from t_emp
</select>

</mapper>
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④创建日志文件log4j.xml

<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE log4j:configuration SYSTEM "log4j.dtd">


<log4j:configuration xmlns:log4j="http://jakarta.apache.org/log4j/">


<appender name="STDOUT" class="org.apache.log4j.ConsoleAppender">
<param name="Encoding" value="UTF-8" />
<layout class="org.apache.log4j.PatternLayout">
<param name="ConversionPattern" value="%-5p %d{MM-dd HH:mm:ss,SSS}
%m	(%F:%L) \n" />
</layout>
</appender>
<logger name="java.sql">
<level value="debug" />
</logger>
<logger name="org.apache.ibatis">
<level value="info" />
</logger>
<root>
<level value="debug" />
<appender-ref ref="STDOUT" />
</root>
</log4j:configuration>
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4.6、创建Spring的配置文件并配置

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:context="http://www.springframework.org/schema/context" xsi:schemaLocation="http://www.springframework.org/schema/beans
http://www.springframework.org/schema/beans/spring-beans.xsd http://www.springframework.org/schema/context https://www.springframework.org/schema/context/spring-context.xsd">

<!--扫描组件-->
<context:component-scan base-package="com.softeem.ssm">
<context:exclude-filter type="annotation" expression="org.springframework.stereotype.Controller"/>
</context:component-scan>

<!-- 引入jdbc.properties -->
<context:property-placeholder location="classpath:jdbc.properties">
</context:property-placeholder>

<!-- 配置Druid数据源 -->
<bean id="dataSource" class="com.alibaba.druid.pool.DruidDataSource">
<property name="driverClassName" value="${jdbc.driver}"></property>
<property name="url" value="${jdbc.url}"></property>
<property name="username" value="${jdbc.username}"></property>
<property name="password" value="${jdbc.password}"></property>
</bean>

<!-- 配置用于创建SqlSessionFactory的工厂bean -->
<bean class="org.mybatis.spring.SqlSessionFactoryBean">
<!-- 设置MyBatis配置文件的路径（可以不设置） -->
<property name="configLocation" value="classpath:mybatis-config.xml">
</property>
<!-- 设置数据源 -->
<property name="dataSource" ref="dataSource"></property>
<!-- 设置类型别名所对应的包 -->
<property name="typeAliasesPackage" value="com.softeem.ssm.pojo">
</property>
<!--
设置映射文件的路径
若映射文件所在路径和mapper接口所在路径一致，则不需要设置
-->
<!--
<property name="mapperLocations" value="classpath:mapper/*.xml">
</property>
-->
</bean>


<!--
配置mapper接口的扫描配置
由mybatis-spring提供，可以将指定包下所有的mapper接口创建动态代理 并将这些动态代理作为IOC容器的bean管理
-->
<bean class="org.mybatis.spring.mapper.MapperScannerConfigurer">
<property name="basePackage" value="com.softeem.ssm.mapper"></property>
</bean>


</beans>

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4.7、测试功能
①创建组件
实体类Employee

public class Employee {


private Integer empId;


private String empName;


private Integer age;


private String sex;


private String email;


public Employee() {
}


public Employee(Integer empId, String empName, Integer age, String sex, String email) {
this.empId = empId; this.empName = empName; this.age = age; this.sex = sex; this.email = email;
}


public Integer getEmpId() { 
return empId;
}


public void setEmpId(Integer empId) { 
this.empId = empId;
}


public String getEmpName() { 
return empName;
}


public void setEmpName(String empName) { 
this.empName = empName;
}


public Integer getAge() { 
return age;
}


public void setAge(Integer age) { 
this.age = age;
}


public String getSex() { 
return sex;
}

public void setSex(String sex) { 
this.sex = sex;
}

public String getEmail() { 
return email;
}

public void setEmail(String email) { 
this.email = email;
}
}
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创建控制层组件EmployeeController

@Controller
public class EmployeeController {

@Autowired
private EmployeeService employeeService;

@RequestMapping(value = "/employee/page/{pageNum}", method = RequestMethod.GET)
public String getEmployeeList(Model model, @PathVariable("pageNum") Integer pageNum){
PageInfo<Employee> page = employeeService.getEmployeeList(pageNum); model.addAttribute("page", page);
return "employee_list";
}

}
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创建接口EmployeeService

public interface EmployeeService {
PageInfo<Employee> getEmployeeList(Integer pageNum);
}
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创建实现类EmployeeServiceImpl

@Service
public class EmployeeServiceImpl implements EmployeeService {

@Autowired
private EmployeeMapper employeeMapper;

@Override
public PageInfo<Employee> getEmployeeList(Integer pageNum) { 
PageHelper.startPage(pageNum, 4);
List<Employee> list = employeeMapper.getEmployeeList(); PageInfo<Employee> page = new PageInfo<>(list, 5); return page;
}
}
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②创建页面

<!DOCTYPE html>
<html lang="en" xmlns:th="http://www.thymeleaf.org">
<head>
<meta charset="UTF-8">
<title>Employee Info</title>
<link rel="stylesheet" th:href="@{/static/css/index_work.css}">
</head>
<body>

<table>
<tr>
<th colspan="6">Employee Info</th>
</tr>
<tr>
<th>emp_id</th>
<th>emp_name</th>
<th>age</th>
<th>sex</th>
<th>email</th>
<th>options</th>
</tr>
<tr th:each="employee : ${page.list}">
<td th:text="${employee.empId}"></td>
<td th:text="${employee.empName}"></td>
<td th:text="${employee.age}"></td>
<td th:text="${employee.sex}"></td>
<td th:text="${employee.email}"></td>
<td>
<a href="">delete</a>
<a href="">update</a>
</td>
</tr>
<tr>
<td colspan="6">
<span th:if="${page.hasPreviousPage}">
<a th:href="@{/employee/page/1}">首页</a>
<a th:href="@{'/employee/page/'+${page.prePage}}">上一页</a>
</span>


<span th:each="num : ${page.navigatepageNums}">
<a th:if="${page.pageNum==num}" th:href="@{'/employee/page/'+${num}}" th:text="'['+${num}+']'" style="color: red;"></a>
<a th:if="${page.pageNum!=num}" th:href="@{'/employee/page/'+${num}}" th:text="${num} "></a>
</span>


<span th:if="${page.hasNextPage}">
<a th:href="@{'/employee/page/'+${page.nextPage}}">下一页</a>
<a th:href="@{'/employee/page/'+${page.pages}}">末页</a>
</span>
</td>
</tr>
</table>
</body>
</html>
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③访问测试分页功能
localhost:8080/employee/page/1