Spring Bean中的自动装配——byType

自动装配byType即通过查找类属性在配置文件中bean中定义的class属性来注入，而不是通过类属性名与配置文件中bean的id属性来匹配的。

如下例：

package com.lwf.bean;

public class Bean2 {

	private Bean3 bean3;
	private Bean4 bean4;
	private Bean5 bean5;
	
	public Bean3 getBean3() {
		return bean3;
	}
	public void setBean3(Bean3 bean3) {
		this.bean3 = bean3;
	}
	public Bean4 getBean4() {
		return bean4;
	}
	public void setBean4(Bean4 bean4) {
		this.bean4 = bean4;
	}
	public Bean5 getBean5() {
		return bean5;
	}
	public void setBean5(Bean5 bean5) {
		this.bean5 = bean5;
	}
	
}

 

package com.lwf.bean;

import java.util.Date;

public class Bean3 {

	private int id;
	private String name;
	
	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;
	}
}

 

package com.lwf.bean;

public class Bean4 {

	private int id;
	private String name;
	
	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;
	}
}

 

package com.lwf.bean;

public class Bean5 {

	private int age;

	public int getAge() {
		return age;
	}

	public void setAge(int age) {
		this.age = age;
	}
	
}

 

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"
		xmlns:aop="http://www.springframework.org/schema/aop"
		xmlns:tx="http://www.springframework.org/schema/tx"
		xsi:schemaLocation="
			http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-2.5.xsd
			http://www.springframework.org/schema/aop http://www.springframework.org/schema/aop/spring-aop-2.5.xsd
			http://www.springframework.org/schema/tx http://www.springframework.org/schema/tx/spring-tx-2.5.xsd"
default-autowire="byType"			
>

	<bean id="bean2" class="com.lwf.bean.Bean2"/>
	<bean id="bean5ref" class="com.lwf.bean.Bean5">
			<property name="age" value="33"></property>
	</bean>
	
	<bean id="parentBean" abstract="true">
		<property name="id" value="1"/>
		<property name="name" value="zhang"/>
	</bean>
	
	<bean id="bean3ref" class="com.lwf.bean.Bean3" parent="parentBean"/>
	<bean id="bean4ref" class="com.lwf.bean.Bean4" parent="parentBean"/>
</beans>

 

可以看到配置文件改为byType。

测试类：

package com.lwf.client;

import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;

import com.lwf.bean.Bean2;

public class Client {
	public static void main(String[] args) {
	
		
		ApplicationContext ctx = new ClassPathXmlApplicationContext("applicationContext*.xml");
		Bean2 bean2 = (Bean2)ctx.getBean("bean2");
		System.out.println(bean2.getBean3().getName());
		System.out.println(bean2.getBean3().getId());
		System.out.println(bean2.getBean4().getId());
		System.out.println(bean2.getBean4().getName());
		System.out.println(bean2.getBean5().getAge());
	}
}

 

 

注：在这次测试中，Bean3中删除了Date属性，这次因为在测试的时候发现自己写的日期转化类在byType下报错。

本次测试结果：

2010-05-19 17:08:39,732 INFO [org.springframework.context.support.ClassPathXmlApplicationContext] - Refreshing org.springframework.context.support.ClassPathXmlApplicationContext@19fcc69: display name [org.springframework.context.support.ClassPathXmlApplicationContext@19fcc69]; startup date [Wed May 19 17:08:39 CST 2010]; root of context hierarchy
2010-05-19 17:08:39,888 INFO [org.springframework.beans.factory.xml.XmlBeanDefinitionReader] - Loading XML bean definitions from file [D:\workdirlocal\spring_autowire\bin\applicationContext.xml]
2010-05-19 17:08:40,201 INFO [org.springframework.context.support.ClassPathXmlApplicationContext] - Bean factory for application context [org.springframework.context.support.ClassPathXmlApplicationContext@19fcc69]: org.springframework.beans.factory.support.DefaultListableBeanFactory@20be79
2010-05-19 17:08:40,263 INFO [org.springframework.beans.factory.support.DefaultListableBeanFactory] - Pre-instantiating singletons in org.springframework.beans.factory.support.DefaultListableBeanFactory@20be79: defining beans [bean2,bean5ref,parentBean,bean3ref,bean4ref]; root of factory hierarchy
zhang
1
1
zhang
33