当singleton Bean依赖propotype Bean，可以使用在配置Bean添加look-method来解决

Posted 2020-08-07 指尖上的艺术

在Spring里面，当一个singleton bean依赖一个prototype bean，因为singleton bean是单例的，因此prototype bean在singleton bean里面也会变成单例.

这个怎么解决呢？？？可以使用Spring提供的lookup-method来注入。

举例说明：先列出相关类：代码中的说明足够说明问题。user类：prototype bean

package com.cn.pojo;

import java.io.Serializable;

public class User implements Serializable{

	/**
	 * 
	 */
	private static final long serialVersionUID = 1L;
	
	private int userId;
	private String userName;
	private String userPwd;
	private String userInfo;
	public int getUserId() {
		return userId;
	}
	public void setUserId(int userId) {
		this.userId = userId;
	}
	public String getUserName() {
		return userName;
	}
	public void setUserName(String userName) {
		this.userName = userName;
	}
	public String getUserPwd() {
		return userPwd;
	}
	public void setUserPwd(String userPwd) {
		this.userPwd = userPwd;
	}
	public String getUserInfo() {
		return userInfo;
	}
	public void setUserInfo(String userInfo) {
		this.userInfo = userInfo;
	} 
    
	
}

 LookupMethod类：singleton bean

package com.cn.springTest;

import com.cn.pojo.User;

/**
 * LookupMethod为singleton,user为propotype
 * 当singleton Bean依赖propotype Bean，可以使用在配置Bean添加look-method来解决
 * @author Administrator
 *
 */
public class LookupMethod {
		private User user;

		public User getUser() {
			return user;
		}

		public void setUser(User user) {
			this.user = user;
		}
		
}

核心配置文件：

<!-- user userbean -->
	<bean id ="user" class="com.cn.pojo.User" scope="prototype">
	   <property name="userId" value="1" />
	   <property name="userName" value="userName" />
	   <property name="userPwd" value="userPwd" />
	   <property name="userInfo" value="userInfo" />
	</bean>
	
	<!-- lookupMethod  LookupMethod为单例，user为原型的获取实例-->
	<bean id ="lookupMethod" class="com.cn.springTest.LookupMethod">
		<!-- <property name="user" ref="user"/> -->  <!-- 这种写法会将user当着单例来获取-->
	    <lookup-method name="getUser" bean="user"/><!--lookup-method方式会将user当着原型来获取-->
	</bean>

 

测试类：SpringLookupMethod

import com.cn.util.SpringContextUtil;

public class SpringLookupMethod {

	public static void main(String[] args) {
		ApplicationContext actx = new ClassPathXmlApplicationContext("ApplicationContext.xml");
		actx.getBean("springContextUtil");
		LookupMethod lookupMethod = (LookupMethod) SpringContextUtil.getBean("lookupMethod");
		System.out.println(lookupMethod);
		LookupMethod lookupMethod1 = (LookupMethod) SpringContextUtil.getBean("lookupMethod");
		System.out.println(lookupMethod1);
		System.out.println(lookupMethod.getUser());
		System.out.println(lookupMethod1.getUser());
		System.out.println(lookupMethod.getUser());
		System.out.println(lookupMethod1.getUser());
	}

}

 

这样的测试足够说明问题。