Bean的循环依赖问题全面解析

package com.powernode.spring6.bean;
/**
 * @author 动力节点
 * @version 1.0
 * @className Husband
 * @since 1.0
 **/
public class Husband {
    private String name;
    private Wife wife;
}

package com.powernode.spring6.bean;
/**
 * @author 动力节点
 * @version 1.0
 * @className Wife
 * @since 1.0
 **/
public class Wife {
    private String name;
    private Husband husband;
}

package com.powernode.spring6.bean;
/**
 * @author 动力节点
 * @version 1.0
 * @className Husband
 * @since 1.0
 **/
public class Husband {
    private String name;
    private Wife wife;
    public void setName(String name) {
        this.name = name;
    }
    public String getName() {
        return name;
    }
    public void setWife(Wife wife) {
        this.wife = wife;
    }
    // toString()方法重写时需要注意：不能直接输出wife，输出wife.getName()。要不然会出现递归导致的栈内存溢出错误。
    @Override
    public String toString() {
        return "Husband{" +
                "name='" + name + '\'' +
                ", wife=" + wife.getName() +
                '}';
    }
}

package com.powernode.spring6.bean;
/**
 * @author 动力节点
 * @version 1.0
 * @className Wife
 * @since 1.0
 **/
public class Wife {
    private String name;
    private Husband husband;
    public void setName(String name) {
        this.name = name;
    }
    public String getName() {
        return name;
    }
    public void setHusband(Husband husband) {
        this.husband = husband;
    }
    // toString()方法重写时需要注意：不能直接输出husband，输出husband.getName()。要不然会出现递归导致的栈内存溢出错误。
    @Override
    public String toString() {
        return "Wife{" +
                "name='" + name + '\'' +
                ", husband=" + husband.getName() +
                '}';
    }
}

<?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="husbandBean" class="com.powernode.spring6.bean.Husband" scope="singleton">
        <property name="name" value="张三"/>
        <property name="wife" ref="wifeBean"/>
    </bean>
    <bean id="wifeBean" class="com.powernode.spring6.bean.Wife" scope="singleton">
        <property name="name" value="小花"/>
        <property name="husband" ref="husbandBean"/>
    </bean>
</beans>

package com.powernode.spring6.test;
import com.powernode.spring6.bean.Husband;
import com.powernode.spring6.bean.Wife;
import org.junit.Test;
import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;
/**
 * @author 动力节点
 * @version 1.0
 * @className CircularDependencyTest
 * @since 1.0
 **/
public class CircularDependencyTest {
    @Test
    public void testSingletonAndSet(){
        ApplicationContext applicationContext = new ClassPathXmlApplicationContext("spring.xml");
        Husband husbandBean = applicationContext.getBean("husbandBean", Husband.class);
        Wife wifeBean = applicationContext.getBean("wifeBean", Wife.class);
        System.out.println(husbandBean);
        System.out.println(wifeBean);
    }
}