从头开始学Spring—02基于XML管理bean

目录

1.实验一：入门案例

2.实验二：获取bean

3.实验三：依赖注入之setter注入

4.实验四：依赖注入之构造器注入

5.实验五：特殊值处理

6.实验六：为类类型属性赋值

7.实验七：为数组类型属性赋值

8.实验八：为集合类型属性赋值

9.实验九：p命名空间

10.实验十：引入外部属性文件(以jdbc为例)

11.实验十一：bean的作用域

12.实验十二：bean的生命周期

13.实验十三：FactoryBean

14.实验十四：基于xml的自动装配

1.实验一：入门案例

①创建Maven Module

②引入依赖

<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0"
         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>

    <groupId>org.example</groupId>
    <artifactId>spring01</artifactId>
    <version>1.0-SNAPSHOT</version>
    <packaging>jar</packaging>

    <dependencies>
        <!-- 基于Maven依赖传递性，导入spring-context依赖即可导入当前所需所有jar包 -->
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-context</artifactId>
            <version>5.3.1</version>
        </dependency>
        <!-- junit测试 -->
        <dependency>
        <groupId>junit</groupId>
        <artifactId>junit</artifactId>
            <version>4.12</version>
            <scope>test</scope>
        </dependency>
    </dependencies>

</project>

③创建类

public class HeloWorld {
    public void sayHello(){
        System.out.println("test spring~~~");
    }
}

④创建Spring的配置文件

⑤在Spring的配置文件中配置bean

<!--
    配置HelloWorld所对应的bean，即将HelloWorld的对象交给Spring的IOC容器管理
    通过bean标签配置IOC容器所管理的bean
    属性：
    id：设置bean的唯一标识
    class：设置bean所对应类型的全类名
-->
<bean id="helloworld" class="com.ykx.spring.pojo.HelloWorld"></bean>

⑥创建测试类对象

@Test
public void test(){
    //获取IOC容器
    ApplicationContext ioc = new ClassPathXmlApplicationContext("applicationContext.xml");
    HelloWorld helloWorld = (HelloWorld) ioc.getBean("helloworld");
    helloWorld.sayHello();
}

⑦思路

⑧注意

2.实验二：获取bean

①方式一：根据id获取

@Test
public void test(){
    //获取IOC容器
    ApplicationContext ioc = new ClassPathXmlApplicationContext("spring-ioc.xml");
    //获取Bean
    Student studentOne = (Student) ioc.getBean("studentOne");
    System.out.println(studentOne);
}

②方式二：根据类型获取

@Test
public void test2(){
    //获取IOC容器
    ApplicationContext ioc = new ClassPathXmlApplicationContext("spring-ioc.xml");
    //获取Bean
    Student student = ioc.getBean(Student.class);
    System.out.println(student);
}

③方式三：根据id和类型

@Test
public void test3(){
    //获取IOC容器
    ApplicationContext ioc = new ClassPathXmlApplicationContext("spring-ioc.xml");
    //获取Bean
    Student student = ioc.getBean("studentOne",Student.class);
    System.out.println(student);
}

④注意

⑤扩展

⑥结论

3.实验三：依赖注入之setter注入

①创建Student类

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 + '\'' +
                '}';
    }
}

②配置bean时为属性赋值

<bean id="studentTwo" class="com.ykx.spring.pojo.Student">
    <!-- property标签：通过组件类的setXxx()方法给组件对象设置属性 -->
    <!-- name属性：指定属性名（这个属性名是getXxx()、setXxx()方法定义的，和成员变量无关）
    -->
    <!-- value属性：指定属性值 -->
    <property name="sid" value="1001"></property>
    <property name="sname" value="张三"></property>
    <property name="age" value="23"></property>
    <property name="gender" value="男"></property>
</bean>

 ③测试

@Test
public void test(){
    //获取IOC容器
    ApplicationContext ioc = new ClassPathXmlApplicationContext("spring-ioc.xml");
    //获取Bean
    Student student = ioc.getBean("studentTwo",Student.class);
    System.out.println(student);
}

4.实验四：依赖注入之构造器注入

①在Student类中添加有参构造

public Student() {
}

public Student(Integer sid, String sname, Integer age, String gender) {
    this.sid = sid;
    this.sname = sname;
    this.age = age;
    this.gender = gender;
}

②配置bean

<bean id="studentThree" class="com.ykx.spring.pojo.Student">
    <constructor-arg value="1002"></constructor-arg>
    <constructor-arg value="李四"></constructor-arg>
    <constructor-arg value="33"></constructor-arg>
    <constructor-arg value="女"></constructor-arg>
</bean>

③测试

@Test
public void test5(){
    //获取IOC容器
    ApplicationContext ioc = new ClassPathXmlApplicationContext("spring-ioc.xml");
    //获取Bean
    Student student = ioc.getBean("studentThree",Student.class);
    System.out.println(student);
}

5.实验五：特殊值处理

①字面量赋值

②null值

③xml实体

④CDATA节

6.实验六：为类类型属性赋值

①创建班级类Clazz

public class Clazz {

    private Integer clazzId;
    private String clazzName;

    public Clazz() {
    }

    public Clazz(Integer clazzId, String clazzName) {
        this.clazzId = clazzId;
        this.clazzName = clazzName;
    }

    public Integer getClazzId() {
        return clazzId;
    }
    public void setClazzId(Integer clazzId) {
        this.clazzId = clazzId;
    }
    public String getClazzName() {
        return clazzName;
    }
    public void setClazzName(String clazzName) {
        this.clazzName = clazzName;
    }
    @Override
    public String toString() {
        return "Clazz{" +
                "clazzId=" + clazzId +
                ", clazzName='" + clazzName + '\'' +
                '}';
    }

}

②修改Student类

③方式一：引用外部已声明的bean

<bean id="clazzOne" class="com.ykx.spring.pojo.Clazz">
    <property name="clazzId" value="1111"></property>
    <property name="clazzName" value="财源滚滚班"></property>
</bean>

<bean id="studentFive" class="com.ykx.spring.pojo.Student">
    <property name="sid" value="1004"></property>
    <property name="sname" value="赵六"></property>
    <property name="age" value="26"></property>
    <property name="gender" value="女"></property>
    <!-- ref属性：引用IOC容器中某个bean的id，将所对应的bean为属性赋值 -->
    <property name="clazz" ref="clazzOne"></property>
</bean>

测试

@Test
public void test6(){
    //获取IOC容器
    ApplicationContext ioc = new ClassPathXmlApplicationContext("spring-ioc.xml");
    //获取Bean
    Student student = ioc.getBean("studentFive",Student.class);
    System.out.println(student);
}

④方式二：内部bean

<bean id="studentSix" class="com.ykx.spring.pojo.Student">
    <property name="sid" value="1004"></property>
    <property name="sname" value="赵六"></property>
    <property name="age" value="26"></property>
    <property name="gender" value="女"></property>
    <property name="clazz">
        <!-- 在一个bean中再声明一个bean就是内部bean -->
        <!-- 内部bean只能用于给属性赋值，不能在外部通过IOC容器获取，因此可以省略id属性 -->
        <bean id="clazzInner" class="com.ykx.spring.pojo.Clazz">
            <property name="clazzId" value="2222"></property>
            <property name="clazzName" value="远大前程班"></property>
        </bean>
    </property>
</bean>

⑤方式三：级联属性赋值

<bean id="studentSeven" class="com.ykx.spring.pojo.Student">
    <property name="sid" value="1004"></property>
    <property name="sname" value="赵六"></property>
    <property name="age" value="26"></property>
    <property name="gender" value="女"></property>
    <!-- 一定先引用某个bean为属性赋值，才可以使用级联方式更新属性 -->
    <property name="clazz" ref="clazzOne"></property>
    <property name="clazz.clazzId" value="3333"></property>
    <property name="clazz.clazzName" value="最强王者班"></property>
</bean>

7.实验七：为数组类型属性赋值

①修改Student类

在Student类中添加以下代码：

private String[] hobbies;

public String[] getHobbies() {
    return hobbies;
}

public void setHobbies(String[] hobbies) {
    this.hobbies = hobbies;
}

②配置bean

<bean id="studentFour" class="com.ykx.spring.pojo.Student">
    <property name="sid" value="1004"></property>
    <property name="sname" value="赵六"></property>
    <property name="age" value="26"></property>
    <property name="gender" value="女"></property>
    <!-- ref属性：引用IOC容器中某个bean的id，将所对应的bean为属性赋值 -->
    <property name="clazz" ref="clazzOne"></property>
    <property name="hobbies">
        <array>
            <value>lol</value>
            <value>cf</value>
            <value>云顶之弈</value>
            <value>金铲铲之战</value>
        </array>
    </property>
</bean>

8.实验八：为集合类型属性赋值

①为List集合类型属性赋值

在Clazz类中添加以下代码：

private List<Student> students;

public List<Student> getStudents() {
    return students;
}

public void setStudents(List<Student> students) {
    this.students = students;
}

配置bean：.

<bean id="clazzTwo" class="com.ykx.spring.pojo.Clazz">
    <property name="clazzId" value="4444"></property>
    <property name="clazzName" value="Javaee0222"></property>
    <property name="students">
        <list>
            <ref bean="studentOne"></ref>
            <ref bean="studentTwo"></ref>
        </list>
    </property>
</bean>

测试结果：

@Test
public void test7(){
    //获取IOC容器
    ApplicationContext ioc = new ClassPathXmlApplicationContext("spring-ioc.xml");
    //获取Bean
    Clazz clazz = ioc.getBean("clazzTwo", Clazz.class);
    System.out.println(clazz);
}

②为Map集合类型属性赋值

创建教师类

public class Teacher {

    private Integer teacherId;
    private String teacherName;

    public Teacher() {
    }

    public Teacher(Integer teacherId, String teacherName) {
        this.teacherId = teacherId;
        this.teacherName = teacherName;
    }

    public Integer getTeacherId() {
        return teacherId;
    }

    public void setTeacherId(Integer teacherId) {
        this.teacherId = teacherId;
    }

    public String getTeacherName() {
        return teacherName;
    }

    public void setTeacherName(String teacherName) {
        this.teacherName = teacherName;
    }

    @Override
    public String toString() {
        return "Teacher{" +
                "teacherId=" + teacherId +
                ", teacherName='" + teacherName + '\'' +
                '}';
    }
}

在Student类中添加以下代码：

private Map<String, Teacher> teacherMap;

public Map<String, Teacher> getTeacherMap() {
    return teacherMap;
}

public void setTeacherMap(Map<String, Teacher> teacherMap) {
    this.teacherMap = teacherMap;
}

配置bean：

<bean id="teacherOne" class="com.ykx.spring.pojo.Teacher">
    <property name="teacherId" value="10010"></property>
    <property name="teacherName" value="大宝"></property>
</bean>
<bean id="teacherTwo" class="com.ykx.spring.pojo.Teacher">
    <property name="teacherId" value="10086"></property>
    <property name="teacherName" value="二宝"></property>
</bean>
<bean id="studentEight" class="com.ykx.spring.pojo.Student">
<property name="sid" value="1004"></property>
<property name="sname" value="赵六"></property>
<property name="age" value="26"></property>
<property name="gender" value="女"></property>
<!-- ref属性：引用IOC容器中某个bean的id，将所对应的bean为属性赋值 -->
<property name="clazz" ref="clazzOne"></property>
<property name="hobbies">
    <array>
        <value>lol</value>
        <value>cf</value>
        <value>云顶之弈</value>
    </array>
</property>
<property name="teacherMap">
<map>
<entry>
<key>
    <value>10010</value>
</key>
    <ref bean="teacherOne"></ref>
</entry>
    <entry>
        <key>
            <value>10086</value>
        </key>
        <ref bean="teacherTwo"></ref>
    </entry>
</map>
</property>
</bean>

③引用集合类型的bean

使用util:list、util:map标签必须引入相应的命名空间，可以通过idea的提示功能选择

<!--list集合类型的bean-->
<util:list id="students">
    <ref bean="studentOne"></ref>
    <ref bean="studentTwo"></ref>
    <ref bean="studentThree"></ref>
</util:list>
<!--map集合类型的bean-->
<util:map id="teacherMap">
    <entry>
        <key>
            <value>10010</value>
        </key>
        <ref bean="teacherOne"></ref>
    </entry>
    <entry>
        <key>
            <value>10086</value>
        </key>
        <ref bean="teacherTwo"></ref>
    </entry>
</util:map>

<bean id="clazzTwo" class="com.atguigu.spring.bean.Clazz">
    <property name="clazzId" value="4444"></property>
    <property name="clazzName" value="Javaee0222"></property>
    <property name="students" ref="students"></property>
</bean>

<bean id="studentFour" class="com.atguigu.spring.bean.Student">
<property name="id" value="1004"></property>
<property name="name" value="赵六"></property>
<property name="age" value="26"></property>
<property name="sex" value="女"></property>
<!-- ref属性：引用IOC容器中某个bean的id，将所对应的bean为属性赋值 -->
<property name="clazz" ref="clazzOne"></property>
<property name="hobbies">
    <array>
        <value>抽烟</value>
        <value>喝酒</value>
        <value>烫头</value>
    </array>
</property>
<property name="teacherMap" ref="teacherMap"></property>
</bean>

9.实验九：p命名空间

10.实验十：引入外部属性文件(以jdbc为例)

①加入依赖

<!-- MySQL驱动 -->
<dependency>
    <groupId>mysql</groupId>
    <artifactId>mysql-connector-java</artifactId>
    <version>8.0.16</version>
</dependency>
<!-- 数据源 -->
<dependency>
    <groupId>com.alibaba</groupId>
    <artifactId>druid</artifactId>
    <version>1.0.31</version>
</dependency>

②创建外部属性文件

jdbc.user=root
jdbc.password=ykxykx
jdbc.url=jdbc:mysql://localhost:3306/ssm?serverTimezone=UTC
jdbc.driver=com.mysql.cj.jdbc.Driver

③引入属性文件

④配置bean

<bean id="druidDataSource" class="com.alibaba.druid.pool.DruidDataSource">
    <property name="url" value="${jdbc.url}"/>
    <property name="driverClassName" value="${jdbc.driver}"/>
    <property name="username" value="${jdbc.user}"/>
    <property name="password" value="${jdbc.password}"/>
</bean>

⑤测试

@Test
public void test() throws Exception {
    //获取IOC容器
    ApplicationContext ioc = new ClassPathXmlApplicationContext("spring-datasource.xml");
    //获取Bean
    DruidDataSource ds = ioc.getBean(DruidDataSource.class);
    Connection connection = ds.getConnection();
    System.out.println(connection);
}

11.实验十一：bean的作用域

12.实验十二：bean的生命周期

①具体的生命周期过程

②bean的后置处理器

13.实验十三：FactoryBean

①简介

②创建类UserFactoryBean

public class UserFactoryBean implements FactoryBean<User> {

    @Override
    public User getObject() throws Exception {
        return new User();
    }
    @Override
    public Class<?> getObjectType() {
        return User.class;
    }

}

③配置bean

<bean id="user" class="com.ykx.spring.factory.UserFactoryBean"></bean>

④测试

@Test
public void testUserFactoryBean(){
    //获取IOC容器
    ApplicationContext ac = new ClassPathXmlApplicationContext("spring-factory.xml");
    User user = (User) ac.getBean("user");
    System.out.println(user);
}

14.实验十四：基于xml的自动装配

①场景模拟

②配置bean

byType

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

byName

<bean id="userController"
      class="com.ykx.spring.controller.UserController" autowire="byName">
</bean>
<bean id="userService"
      class="com.ykx.spring.service.impl.UserServiceImpl" autowire="byName">
</bean>
<bean id="userServiceImpl"
      class="com.ykx.spring.service.impl.UserServiceImpl" autowire="byName">
</bean>
<bean id="userDao" class="com.ykx.spring.dao.impl.UserDaoImpl"></bean>
<bean id="userDaoImpl" class="com.ykx.spring.dao.impl.UserDaoImpl">
</bean>

③测试

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

}

内容来源于黑马程序员SSM课程的笔记，仅作为学习笔记参考