第五讲：5.1 Spring 自动装配

一，通过名字自动注入
1，复制spring40203 改名为spring40204，修改beans.xml，
xml version="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"
        default-autowire="byName">


<bean id="dog3" class="com.cruise.entity.Dog">
    <property name="name" value="Jack">property>
bean>

<bean id="dog" class="com.cruise.entity.Dog">
    <property name="name" value="Tom">property>
bean>

<bean id="people1" class="com.cruise.entity.People">
    <property name="id" value="1">property>
    <property name="name" value="张三">property>
    <property name="age" value="11">property>
    
bean> 
beans>
2，修改People类，其中Dog的属性名决定装配哪一个bean，例如private Dog dog3(get set toString方法要重新生成);
package com.cruise.entity;

public class People {

    private int id;
    private String name;
    private int age;
    private Dog dog;
    public int getId() {
       return id;
    }
    public void setId(int id) {
       this.id = id;
    }
    public String getName() {
       return name;
    }
    public void setName(String name) {
       this.name = name;
    }
    public int getAge() {
       return age;
    }
    public void setAge(int age) {
       this.age = age;
    }
    public Dog getDog() {
       return dog;
    }
    public void setDog(Dog dog) {
       this.dog = dog;
    }
    @Override
    public String toString() {
       return "People [id=" + id + ", name=" + name + ", age=" + age + ", dog=" + dog.getName() + "]";
    }
}
3，修改T类，运行-测试
package com.cruise.test;

import org.junit.Before;
import org.junit.Test;
import org.springframework.context.support.ClassPathXmlApplicationContext;

import com.cruise.entity.People;

public class T {

    private ClassPathXmlApplicationContext CPXAC=null;
    @Before
    public void setUp() throws Exception {
       CPXAC= new ClassPathXmlApplicationContext("beans.xml");
    }

    @Test
    public void test1() {
       People people1 = (People)CPXAC.getBean("people1");
       System.out.println(people1);
    }
}
二，通过类型自动注入
1，修改beans.xml文件，运行测试，
ps：需要类型唯一，例如：class相同的bean只能有一个，所以把id为dog3的bean注释掉，否则报错
xml version="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"
        default-autowire="byType">



<bean id="dog" class="com.cruise.entity.Dog">
    <property name="name" value="Tom">property>
bean>

<bean id="people1" class="com.cruise.entity.People">
    <property name="id" value="1">property>
    <property name="name" value="张三">property>
    <property name="age" value="11">property>
    
bean> 
beans>
2， 运行 测试(T类不用修改)
    @Test
    public void test1() {
       People people1 = (People)CPXAC.getBean("people1");
       System.out.println(people1);
    }
三，通过构造方法自动注入，此方法与类型方法基本一直，只是需要在People中增加构造方法。
1，修改beans.xml，
xml version="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"
        default-autowire="constructor">



<bean id="dog" class="com.cruise.entity.Dog">
    <property name="name" value="Tom">property>
bean>

<bean id="people1" class="com.cruise.entity.People">
    <property name="id" value="1">property>
    <property name="name" value="张三">property>
    <property name="age" value="11">property>
    
bean> 
beans>
2，修改People类，添加构造方法，全参构造方法中加一个Dog即可，
public People(Dog dog) {
       super();
       this.dog = dog;
    }
    public People() {
       super();
    }

3，运行测试
@Test
    public void test1() {
       People people1 = (People)CPXAC.getBean("people1");
       System.out.println(people1);
    }