SpringWeb(SpringMVC)

SpringWEB 运行流程图

搭建 SpringWeb

导入spring-webmvc包

<dependency>
    <groupId>org.springframeworkgroupId>
    <artifactId>spring-webmvcartifactId>
    <version>5.2.2.RELEASEversion>
dependency>

在 web.xml 文件中配置 DispatcherServlet

 

    <servlet>
        <servlet-name>applicationservlet-name>
        <servlet-class>org.springframework.web.servlet.DispatcherServletservlet-class>
        <init-param>
            <param-name>contextConfigLocationparam-name>
            <param-value>classpath:spring.xmlparam-value>
        init-param>
        <load-on-startup>0load-on-startup>
    servlet>
    
    <servlet-mapping>
        <servlet-name>applicationservlet-name>
        <url-pattern>/url-pattern>
    servlet-mapping>

开启 springmvc 注解(spring核心配置文件)

    
    <mvc:annotation-driven>mvc:annotation-driven>

处理器类搭建

• RestController定义web层的类，Spring 会扫描使用了@RestController 标识的类，然后将类加入到 Spring IOC 容器 中，注入依赖；
• @RequestMapping 注解是一个用来处理请求地址映射的注解，可用于类或方法上。

常用注解： 

1. @RequestMapping(path = "/")：post请求和get请求都可以
2. @GetMapping(path = "/")：用于get请求
3. @PostMapping(path = "/")：用于post请求
4. @RequestParam：名字不一致时，RequestParam可以绑定，其中有required默认为false，接收的参数可以为空，required=true时就不能为空，可以继续设置defaultValue作为默认值
5.  @RequestHeader(“user-Agent”)：接收请求头中的内容
6. @RequestBody：当前端传来是json形式，用@RequestBody来接收
7. @DateTimeFormat(pattern = "yyyy-MM-dd")：在日期形式的属性前加

//RestController定义web层的类
@RestController
@RequestMapping(path = "/loginCtl")
public class LoginCtl {
 
    @Autowired
    LoginService loginService;
    @RequestMapping(path = "/test")
    public String Login(){
        return "hello world!!!!!!!";
    }
 
 
    //path与value都可以 定义映射地址
    @RequestMapping(path = "/test1")
    public String Login1(){
        return "hello world1";
    }
 
    //path与value都可以 定义映射地址
    @GetMapping(path = "l")
    public String Login2(HttpServletRequest httpServletRequest){
 
    String account =  httpServletRequest.getParameter("account");
    String password =  httpServletRequest.getParameter("password");
        System.out.println(account+":"+password);
        return "hello world1";
    }

    @DateTimeFormat(pattern = "yyyy-MM-dd")
    private Date password;

public class DemoInterceptor implements HandlerInterceptor {
    //preHandle预处理
    @Override
    public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler) throws Exception {
        System.out.println("进入到拦截器");
        return true;
     /*
     true是离开拦截器，进目标处理器
     false是不进处理器
      */
    }
}

    
 
    <mvc:interceptors>
        <mvc:interceptor>
            <mvc:mapping path="/**"/>
            
            
            <mvc:exclude-mapping path="/loginCtl/test1"/>
            <bean id="demo" class="com.yyds.ssm.util.DemoInterceptor">bean>
        mvc:interceptor>
    mvc:interceptors>