峰Spring4学习（4）spring自动装配

一、自动装配：

Model类：

People.java:

package com.cy.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() + "]";
    }
    
    
}

Dog.java:

package com.cy.entity;

public class Dog {
    private String name;

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }
    
    
}

beans.xml  spring加载bean配置文件：

<?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="dog" class="com.cy.entity.Dog">
         <property name="name" value="Jack"></property>
     </bean>
     
     <bean id="dog2" class="com.cy.entity.Dog">
         <property name="name" value="Tom"></property>
     </bean>
     
     <bean id="people1" class="com.cy.entity.People">
         <property name="id" value="1"></property>
         <property name="name" value="张三"></property>
         <property name="age" value="11"></property>
     </bean>
     
     
</beans>

测试代码：

T.java:

package com.cy.test;

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

import com.cy.entity.People;

public class T {
    
    private ApplicationContext ac;

    @Before
    public void setUp() throws Exception {
         ac=new ClassPathXmlApplicationContext("beans.xml");
    }
    
    @Test
    public void test() {
        People people = (People) ac.getBean("people1");
        System.out.println(people);  //People [id=1, name=张三, age=11, dog=Jack]
    }
    
}

二、方法注入：

<?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">

    <！-- prototype配置dog为多例模式 -->
    <bean id="dog" class="com.java1234.entity.Dog" scope="prototype">
        <property name="name" value="Jack"></property>
    </bean>
    
    
    
    <bean id="people1" class="com.java1234.entity.People">
        <property name="id" value="1"></property>
        <property name="name" value="张三"></property>
        <property name="age" value="11"></property>
        <lookup-method name="getDog" bean="dog"/>
    </bean>
    
</beans>

People中的getDog为抽象方法，这样在getDog时，由spring来注入具体的dog：

People.java:

package com.java1234.entity;


public abstract 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 abstract Dog getDog();
    
    public void setDog(Dog dog) {
        this.dog = dog;
    }
    @Override
    public String toString() {
        return "People [id=" + id + ", name=" + name + ", age=" + age
                + ", dog=" + dog.getName() + "]";
    }
    
}

测试代码：

package com.java1234.test;

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

import com.java1234.entity.People;

public class T {

    private ApplicationContext ac;

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

    @Test
    public void test1() {
        People people=(People)ac.getBean("people1");
        People people2=(People)ac.getBean("people1");
        System.out.println(people.getDog()==people2.getDog());        //false  people每次装配的dog都不一样
        
        System.out.println(ac.getBean("dog")==ac.getBean("dog"));    //false　　dog为多例，每次获取都不一样
    }
    

}

三、方法替换，不常用，了解下就行了：

People.java:

package com.java1234.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() {
        Dog dog=new Dog();
        dog.setName("Jack");
        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() + "]";
    }
    

}

People2.java:

package com.java1234.entity;

import java.lang.reflect.Method;

import org.springframework.beans.factory.support.MethodReplacer;


public class People2 implements MethodReplacer {

    @Override
    public Object reimplement(Object arg0, Method arg1, Object[] arg2)
            throws Throwable {
        Dog dog=new Dog();
        dog.setName("Tom");
        return dog;
    }

}

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">

    
    <bean id="people1" class="com.java1234.entity.People">
        <property name="id" value="1"></property>
        <property name="name" value="张三"></property>
        <property name="age" value="11"></property>
        <replaced-method name="getDog" replacer="people2"></replaced-method><!-- people1中的getDog方法被替换，被people2中的方法替换掉了 -->
    </bean>
    
    <bean id="people2" class="com.java1234.entity.People2"></bean>
</beans>

测试代码：

package com.java1234.test;

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

import com.java1234.entity.People;

public class T {

    private ApplicationContext ac;

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

    @Test
    public void test1() {
        People people=(People)ac.getBean("people1");
        System.out.println(people.getDog().getName());
    }
    

}