​

​

<dependencies>
    
    <dependency>
        <groupId>org.springframeworkgroupId>
        <artifactId>spring-contextartifactId>
        <version>5.3.1version>
    dependency>
    
    <dependency>
        <groupId>junitgroupId>
        <artifactId>junitartifactId>
        <version>4.12version>
        <scope>testscope>
    dependency>
dependencies>

public class HelloWorld {
    public void sayHello() {
        System.out.println("hello world");
    }
}

"1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
	   xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
	   xsi:schemaLocation="http://www.springframework.org/schema/beans 
        http://www.springframework.org/schema/beans/spring-beans.xsd">
 
	
	<bean id="hello" class="com.chenyixin.ssm.HelloWorld"/>
beans>

public class HelloWorldTest {
 
    @Test
    public void sayHello() {
        //  从配置文件中获取 IOC 容器对象
        ApplicationContext context = new ClassPathXmlApplicationContext("applicationContext.xml");
 
        // 从 IOC 容器对象中获取bean，也就是组件对象
        HelloWorld hello = (HelloWorld) context.getBean("hello");
 
        hello.sayHello();
        // hello world
    }
}

​

 
public class Student {
    private Integer sid;
    private String sname;
    private Integer age;
    private String gender;
 
    public Student() {
    }
 
    public Student(Integer sid, String sname, Integer age, String gender) {
        this.sid = sid;
        this.sname = sname;
        this.age = age;
        this.gender = gender;
    }
 
    public Integer getSid() {
        return sid;
    }
 
    public void setSid(Integer sid) {
        this.sid = sid;
    }
 
    public String getSname() {
        return sname;
    }
 
    public void setSname(String sname) {
        this.sname = sname;
    }
 
    public Integer getAge() {
        return age;
    }
 
    public void setAge(Integer age) {
        this.age = age;
    }
 
    public String getGender() {
        return gender;
    }
 
    public void setGender(String gender) {
        this.gender = gender;
    }
 
    @Override
    public String toString() {
        return "Student{" +
                "sid=" + sid +
                ", sname='" + sname + '\'' +
                ", age=" + age +
                ", gender='" + gender + '\'' +
                '}';
    }
}

	<bean id="studentOne" class="com.chenyixin.ssm.pojo.Student"/>

         // 获取 ioc 容器
        ApplicationContext ioc = new ClassPathXmlApplicationContext("spring-ioc.xml");
        // 获取 bean 对象
        // 1、根据id获取bean
        Student studentOne1 = (Student) ioc.getBean("studentOne");
        System.out.println(studentOne1);
        // Student{sid=null, sname='null', age=null, gender='null'}

        // 2、根据类型获取 bean
        Student studentOne2 = ioc.getBean(Student.class);
        System.out.println(studentOne2);
        // Student{sid=null, sname='null', age=null, gender='null'}

	"studentOne" class="com.chenyixin.ssm.pojo.Student"/>
	<bean id="studentTwo" class="com.chenyixin.ssm.pojo.Student"/>

<property name="sid" value="1001"/>

② null值

	<bean id="studentFour" class="com.chenyixin.ssm.pojo.Student">
		
		<property name="sid" value="1001"/>
		<property name="sname" value="张三"/>
		<property name="age">
            
			<null/>
		property>
		<property name="gender" value="女"/>
	bean>

注意：

<property name="name" value="null">property>

以上写法，为name所赋的值是字符串null

    private Clazz clazz;
 
    public Clazz getClazz() {
        return clazz;
    }
 
    public void setClazz(Clazz clazz) {
        this.clazz = clazz;
    }
 
    @Override
    public String toString() {
        return "Student{" +
                "sid=" + sid +
                ", sname='" + sname + '\'' +
                ", age=" + age +
                ", gender='" + gender + '\'' +
                ", clazz=" + clazz +
                '}';
    }

③方式一：引用外部已声明的bean

	<bean id="clazzOne" class="com.chenyixin.ssm.pojo.Clazz">
		<property name="cid" value="1111"/>
		<property name="cname" value="最强王者班"/>
	bean>

	<bean id="studentFive" class="com.chenyixin.ssm.pojo.Student">
		<property name="sid" value="1003"/>
		<property name="sname" value="王五"/>
		<property name="age" value="25"/>
		<property name="gender" value="男"/>
		
		<property name="clazzOne" ref="clazz"/>
	bean>

    @Test
    public void testDI4() {
        ApplicationContext ioc = new ClassPathXmlApplicationContext("spring-ioc.xml");
        Student studentFive = ioc.getBean("studentFive", Student.class);
        System.out.println(studentFive);
        // Student{sid=1003, sname='王五', age=25, gender='男', clazz=Clazz{cid=1111, cname='最强王者班'}}
    }

	"studentFive" class="com.chenyixin.ssm.pojo.Student">
		"sid" value="1003"/>
		"sname" value="王五"/>
		"age" value="25"/>
		"gender" value="男"/>
		
		"clazz" value="clazzOne"/>

④ 方式二：内部bean

    private String[] hobbies;
 
    public String[] getHobbies() {
        return hobbies;
    }
 
    public void setHobbies(String[] hobbies) {
        this.hobbies = hobbies;
    }
 
    @Override
    public String toString() {
        return "Student{" +
                "sid=" + sid +
                ", sname='" + sname + '\'' +
                ", age=" + age +
                ", gender='" + gender + '\'' +
                ", hobbies=" + Arrays.toString(hobbies) +
                ", clazz=" + clazz +
                '}';
    }

② 配置bean

    <bean id="studentEight" class="com.chenyixin.ssm.pojo.Student">
		<property name="sid" value="1003"/>
		<property name="sname" value="王五"/>
		<property name="age" value="25"/>
		<property name="gender" value="男"/>
		<property name="hobbies" >
			<array>
				
				
				<value>抽烟value>
				<value>喝酒value>
				<value>烫头value>
			array>
		property>
		<property name="clazz" ref="clazzOne"/>
	bean>

③ 测试

public class Teacher {
    private Integer tid;
    private String tname;
 
    public Teacher() {
    }
 
    public Teacher(Integer tid, String tname) {
        this.tid = tid;
        this.tname = tname;
    }
 
    public Integer getTid() {
        return tid;
    }
 
    public void setTid(Integer tid) {
        this.tid = tid;
    }
 
    public String getTname() {
        return tname;
    }
 
    public void setTname(String tname) {
        this.tname = tname;
    }
 
    @Override
    public String toString() {
        return "Teacher{" +
                "tid=" + tid +
                ", tname='" + tname + '\'' +
                '}';
    }
}

    private Map teacherMap;
 
    public Map getTeacherMap() {
        return teacherMap;
    }
 
    public void setTeacherMap(Map teacherMap) {
        this.teacherMap = teacherMap;
    }
 
    @Override
    public String toString() {
        return "Student{" +
                "sid=" + sid +
                ", sname='" + sname + '\'' +
                ", age=" + age +
                ", gender='" + gender + '\'' +
                ", hobbies=" + Arrays.toString(hobbies) +
                ", teacherMap=" + teacherMap +
                ", clazz=" + clazz +
                '}';
    }

	<bean id="teacherOne" class="com.chenyixin.ssm.pojo.Teacher">
		<property name="tid" value="101"/>
		<property name="tname" value="王老"/>
	bean>
	<bean id="teacherTwo" class="com.chenyixin.ssm.pojo.Teacher">
		<property name="tid" value="102"/>
		<property name="tname" value="刘老"/>
	bean>
 
	<bean id="studentNine" class="com.chenyixin.ssm.pojo.Student">
		<property name="sid" value="1003"/>
		<property name="sname" value="王五"/>
		<property name="age" value="25"/>
		<property name="gender" value="男"/>
		<property name="hobbies" >
			<array>
				<value>篮球value>
				<value>足球value>
				<value>乒乓球value>
			array>
		property>
		<property name="teacherMap">
			<map>
				<entry key="101" value-ref="teacherOne"/>
				<entry key="102" value-ref="teacherTwo"/>
			map>
		property>
		<property name="clazz" ref="clazzOne"/>
	bean>

测试：

    @Test
    public void testDI10() {
        ApplicationContext ioc = new ClassPathXmlApplicationContext("spring-ioc.xml");
        Student studentNine = ioc.getBean("studentNine", Student.class);
        System.out.println(studentNine);
        // Student{sid=1003, sname='王五', age=25, gender='男',
        // hobbies=[篮球, 足球, 乒乓球],
        // teacherMap={101=Teacher{tid=101, tname='王老'}, 102=Teacher{tid=102, tname='刘老'}},
        // clazz=Clazz{cid=3333, cname='荣耀王者班', students=null}}
    }

④ 引用map集合类型的bean（外部bean）

配置bean：

    <bean id="studentTen" class="com.chenyixin.ssm.pojo.Student">
		<property name="sid" value="1005"/>
		<property name="sname" value="田七"/>
		<property name="age" value="35"/>
		<property name="gender" value="男"/>
		<property name="hobbies" >
			<array>
				<value>篮球value>
				<value>足球value>
				<value>乒乓球value>
			array>
		property>
		<property name="teacherMap" ref="studentMap"/>
		<property name="clazz" ref="clazzOne"/>
	bean>
 
	<util:map id="studentMap">
		<entry key="101" value-ref="teacherOne"/>
		<entry key="102" value-ref="teacherTwo"/>
	util:map>

测试：

    @Test
    public void testDI11() {
        ApplicationContext ioc = new ClassPathXmlApplicationContext("spring-ioc.xml");
        Student studentTen = ioc.getBean("studentTen", Student.class);
        System.out.println(studentTen);
        // Student{sid=1005, sname='田七', age=35, gender='男', hobbies=[篮球, 足球, 乒乓球],
        // teacherMap={101=Teacher{tid=101, tname='王老'}, 102=Teacher{tid=102, tname='刘老'}},
        // clazz=Clazz{cid=3333, cname='荣耀王者班', students=null}}
    }

4.9、实验九：p命名空间

引入p命名空间：在标签中写入p: + Alt + Enter ，IDEA会提示所需导入名称空间 + Enter

	<bean id="studentEleven" class="com.chenyixin.ssm.pojo.Student"
		  p:sid="1006" p:sname="小明" p:age="22" p:gender="未知" p:teacherMap-ref="studentMap"/>

测试：

    @Test
    public void testDI12() {
        ApplicationContext ioc = new ClassPathXmlApplicationContext("spring-ioc.xml");
        Student studentEleven = ioc.getBean("studentEleven", Student.class);
        System.out.println(studentEleven);
        // Student{sid=1006, sname='小明', age=22, gender='未知', hobbies=null, 
        // teacherMap={101=Teacher{tid=101, tname='王老'}, 102=Teacher{tid=102, tname='刘老'}},
        // clazz=null}
    }

		
		<dependency>
			<groupId>mysqlgroupId>
			<artifactId>mysql-connector-javaartifactId>
			<version>8.0.16version>
		dependency>
		
		<dependency>
			<groupId>com.alibabagroupId>
			<artifactId>druidartifactId>
			<version>1.0.31version>
		dependency>

② 配置bean

	<bean id="dataSource" class="com.alibaba.druid.pool.DruidDataSource">
		<property name="driverClassName" value="com.mysql.cj.jdbc.Driver"/>
		<property name="url" value="jdbc:mysql://localhost:3306/ssm?serverTimezone=UTC"/>
		<property name="username" value="root"/>
		<property name="password" value="root"/>
	bean>

③ 测试：

    @Test
    public void test() throws SQLException {
        ApplicationContext ioc = new ClassPathXmlApplicationContext("dataSource.xml");
        DruidDataSource dataSource = ioc.getBean(DruidDataSource.class);
        System.out.println(dataSource.getConnection());
        // com.mysql.cj.jdbc.ConnectionImpl@1f1c7bf6
    }

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

③ 配置bean

	
	<context:property-placeholder location="jdbc.properties"/>
 
	<bean id="dataSource" class="com.alibaba.druid.pool.DruidDataSource">
		<property name="driverClassName" value="${jdbc.driver}"/>
		<property name="url" value="${jdbc.url}"/>
		<property name="username" value="${jdbc.username}"/>
		<property name="password" value="${jdbc.password}"/>
	bean>

④ 测试

    @Test
    public void test() throws SQLException {
        ApplicationContext ioc = new ClassPathXmlApplicationContext("dataSource.xml");
        DruidDataSource dataSource = ioc.getBean(DruidDataSource.class);
        System.out.println(dataSource.getConnection());
        // com.mysql.cj.jdbc.ConnectionImpl@1f1c7bf6
    }

4.12 实验十二：bean的作用域

① 概念

在 Spring 中可以通过配置 bean 标签的 scope 属性来指定 bean 的作用域范围，各取值含义参加下表：

如果是在WebApplicationContext环境下还会有另外两个作用域（但不常用）：

public class User {
    private Integer id;
    private String username;
    private String password;
    private Integer age;
 
    public User(Integer id, String username, String password, Integer age) {
        this.id = id;
        this.username = username;
        this.password = password;
        this.age = age;
    }
 
    public User() {
    }
 
    public Integer getId() {
        return id;
    }
 
    public void setId(Integer id) {
        this.id = id;
    }
 
    public String getUsername() {
        return username;
    }
 
    public void setUsername(String username) {
        this.username = username;
    }
 
    public String getPassword() {
        return password;
    }
 
    public void setPassword(String password) {
        this.password = password;
    }
 
    public Integer getAge() {
        return age;
    }
 
    public void setAge(Integer age) {
        this.age = age;
    }
 
    @Override
    public String toString() {
        return "User{" +
                "id=" + id +
                ", username='" + username + '\'' +
                ", password='" + password + '\'' +
                ", age=" + age +
                '}';
    }
}

③ 配置bean

	
	
	
	<bean id="user1" class="com.chenyixin.ssm.pojo.User">
		<property name="id" value="1"/>
		<property name="username" value="张三"/>
		<property name="password" value="zhangsan"/>
		<property name="age" value="19"/>
	bean>
 
	<bean id="user2" class="com.chenyixin.ssm.pojo.User" scope="prototype">
		<property name="id" value="2"/>
		<property name="username" value="李四"/>
		<property name="password" value="lisi"/>
		<property name="age" value="21"/>
	bean>

    @Test
    public void test() {
        ApplicationContext ioc = new ClassPathXmlApplicationContext("User.xml");
        User user11 = ioc.getBean("user1", User.class);
        User user12 = ioc.getBean("user1", User.class);
        System.out.println(user11 == user12); // true
 
        User user21 = ioc.getBean("user2", User.class);
        User user22 = ioc.getBean("user2", User.class);
        System.out.println(user21 == user22); //false
    }

public class User {
    private Integer id;
    private String username;
    private String password;
    private Integer age;
 
    public User(Integer id, String username, String password, Integer age) {
        this.id = id;
        this.username = username;
        this.password = password;
        this.age = age;
    }
 
    public User() {
        System.out.println("生命周期1 实例化");
    }
 
    public Integer getId() {
        return id;
    }
 
    public void setId(Integer id) {
        System.out.println("生命周期2 依赖注入");
        this.id = id;
    }
 
    public String getUsername() {
        return username;
    }
 
    public void setUsername(String username) {
        this.username = username;
    }
 
    public String getPassword() {
        return password;
    }
 
    public void setPassword(String password) {
        this.password = password;
    }
 
    public Integer getAge() {
        return age;
    }
 
    public void setAge(Integer age) {
        this.age = age;
    }
 
    @Override
    public String toString() {
        return "User{" +
                "id=" + id +
                ", username='" + username + '\'' +
                ", password='" + password + '\'' +
                ", age=" + age +
                '}';
    }
    
    public void initMethod() {
        System.out.println("生命周期3 初始化");
    }
 
    public void destroyMethod() {
        System.out.println("生命周期5 销毁");
    }
}

③ 配置 xml：

	
	<bean id="user" class="com.chenyixin.ssm.pojo.User"
		  init-method="initMethod" destroy-method="destroyMethod">
		<property name="id" value="3"/>
		<property name="username" value="admin"/>
		<property name="password" value="123456"/>
		<property name="age" value="23"/>
 	bean>

④ 测试

public class LiftTest {
 
    @Test
    public void testLift() {
        // CofigurableApplicationContext 是 ApplicationContext 的子接口，其中扩展了刷新和关闭容器的方法
        ConfigurableApplicationContext ioc =
                new ClassPathXmlApplicationContext("spring-lift.xml");
        User user = ioc.getBean(User.class);
        System.out.println("生命周期4：" + user.toString());
        ioc.close();
    }
}

结果：

⑤ 注意

⑦ 添加 bean 的后置处理器，bean 生命周期+2步

1、实例化  （无参数构造）

2、依赖注入 （调用 set 方法）

3、bean对象初始化之前操作（由bean的后置处理器负责）

4、初始化，需要通过 bean 的init-method 属性指定初始化的方法

5、bean对象初始化之后操作（由bean的后置处理器负责）

6、调用 bean 对象

7、IOC容器关闭时销毁，需要通过 bean 的 deestroy-method 属性指定销毁的方法

public class UserController {
    private UserService userService;
 
    public UserService getUserService() {
        return userService;
    }
 
    public void setUserService(UserService userService) {
        this.userService = userService;
    }
 
    public void saveUser() {
        userService.saveUser();
    }
}

创建接口UserService

public interface UserService {
    void saveUser();
}

创建类UserServiceImpl实现接口UserService

public class UserServiceImpl implements UserService {
    private UserDao userDao;
 
    public UserDao getUserDao() {
        return userDao;
    }
 
    public void setUserDao(UserDao userDao) {
        this.userDao = userDao;
    }
 
    @Override
    public void saveUser() {
        userDao.saveUser();
    }
}

创建接口UserDao

public interface UserDao {
    void saveUser();
}

创建类UserDaoImpl实现接口UserDao

public class UserDaoImpl implements UserDao {
    @Override
    public void saveUser() {
        System.out.println("保存成功");
    }
}

② 手动配置bean

	<bean id="controller" class="com.chenyixin.ssm.controller.UserController">
		<property name="userService" ref="service"/>
	bean>
	<bean id="service" class="com.chenyixin.ssm.service.impl.UserServiceImpl">
		<property name="userDao" ref="dao"/>
	bean>
	<bean id="dao" class="com.chenyixin.ssm.dao.impl.UserDaoImpl"/>

③ 自动装配

自动装配：

根据指定的策略，在IOC容器中匹配某个bean,自动为bean中的类类型的属性或接口类型的属性赋值

可以通过bean 标签中的autowire属性设置自动装配的策略

        1、no,default:表示不装配，即bean中的属性不会自动匹配某个bean为其属性赋值，此时属性使用默认值

        2、byType:根据要赋值的属性的类型，在IOC容器中匹配某个bean，为属性赋值

                注意：

                        a>若通过类型没有找到任何一个类型匹配的bean，此时不装配，属性使用默认值

                        b>若通过类型找到了多个类型匹配的bean，此时会抛出异常：NoUnqueBeanDefinitionException

                        总结：当使用 byType 实现自动装配时，IOC容器有且只有一个类型匹配的bean能够为属性赋值。

        3、byName:将要赋值的属性的属性名作为bean 的 id 在IOC容器中匹配某个bean，为属性赋值

                总结：当类类型的bean有点多个时，此时可以使用byName实现自动装配

	<bean id="userController" class="com.chenyixin.ssm.controller.UserController" autowire="byType"/>
	<bean id="userService" class="com.chenyixin.ssm.service.impl.UserServiceImpl" autowire="byName"/>
	<bean id="userDao" class="com.chenyixin.ssm.dao.impl.UserDaoImpl"/>

④ 测试

    @Test
    public void test() {
        ApplicationContext ioc = new ClassPathXmlApplicationContext("spring-autowire.xml");
        UserController userController = ioc.getBean(UserController.class);
        userController.saveUser(); //保存成功
    }

5、基于 注解 管理 Bean

5.1、标记与扫描

① 注解的作用

        和 XML 配置文件一样，注解本身并不能执行，注解本身仅仅只是做一个标记，具体的功能是框架检测到注解标记的位置，然后针对这个位置按照注解标记的功能来执行具体操作。

        本质上：所有一切的操作都是 Java 代码来完成的，XML 和注解只是告诉框架中的 Java 代码如何执行。

        举例：元旦联欢会要布置教室，蓝色的地方贴上元旦快乐四个字，红色的地方贴上拉花，黄色的地方贴上气球。 班长做了所有标记，同学们来完成具体工作。墙上的标记相当于我们在代码中使用的注解，后面同学们做的工作，相当于框架的具体操作。

 

② 扫描

Spring 为了知道程序员在哪些地方标记了什么注解，就需要通过扫描的方式，来进行检测。然后根据注解进行后续操作。

③ 新建Maven Module 并引入依赖

		<dependency>
			<groupId>org.springframeworkgroupId>
			<artifactId>spring-contextartifactId>
			<version>5.3.1version>
		dependency>
		
		<dependency>
			<groupId>junitgroupId>
			<artifactId>junitartifactId>
			<version>4.12version>
			<scope>testscope>