spring：实例化类过程中方法执行顺序。

news2025/7/23 22:59:41

如题。在实例化Bean时，会根据配置依次调用方法。在此测试代码如下：

在测试类中继承接口InitializingBean，接口InterfaceUserService（该接口为自定义，只是定义set方法）。

InterfaceUserService，接口InterfaceUserDao不影响测试，

package com.itheima.service.interfaces;


import com.itheima.dao.interfaces.InterfaceUserDao;


/**
 * @copyright 2003-2024
 * @author    qiao wei
 * @date      2024-12-22
 * @version   1.0
 * @brief     
 * @history   name
 *            date
 *            brief
 */
public interface InterfaceUserService {
    
    void show();
    
    void setUserDao001(InterfaceUserDao userDao);
}

测试类UserServiceImpl02

package com.itheima.service.impl;


import org.springframework.beans.factory.InitializingBean;

import com.itheima.dao.interfaces.InterfaceUserDao;
import com.itheima.service.interfaces.InterfaceUserService;


/**
 * @copyright 2003-2024
 * @author    qiao wei
 * @date      2024-12-23
 * @version   1.0
 * @brief     有参构造方法。
 * @history   name
 *            date
 *            brief
 */
public class UserServiceImpl02 implements InterfaceUserService, InitializingBean {
    
    public UserServiceImpl02() {
        System.out.println("类UserServiceImpl02调用无参构造函数。");
    }
    
    public UserServiceImpl02(InterfaceUserDao paramUserDao, double paramValue) {
        this.userDao = paramUserDao;
        this.value01 = paramValue;
        System.out.println("调用带参构造方法");
//        paramUserDao.print();
//        System.out.println("类UserServiceImpl02调用有参构造函数。---" + userDaoABC);
//        System.out.println(value01);
    }
    
    @Override
    public void afterPropertiesSet() throws Exception {
        System.out.println("实现接口InitializingBean的方法afterPropertiesSet");
    }
    
    @Override
    public void show() {
        System.out.println("类UserServiceImpl02的show方法。");
        System.out.println("打印字段数据。userDao：" + userDao + "，value01：" + value01);
        System.out.println(userDaoABC);
    }

    @Override
    public void setUserDao001(InterfaceUserDao userDao) {
        System.out.println("调用属性设置方法。");
        this.userDaoABC = userDao;
    }
    
    private InterfaceUserDao userDao;
    
    private InterfaceUserDao userDaoABC;
    
    private double value01;
}

配置xml，配置构造方法的参数。

<?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:p="http://www.springframework.org/schema/p"
       xmlns:context="http://www.springframework.org/schema/context"
       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-4.0.xsd
       http://www.springframework.org/schema/context 
       http://www.springframework.org/schema/context/spring-context-4.0.xsd
       http://www.springframework.org/schema/tx 
       http://www.springframework.org/schema/tx/spring-tx-4.0.xsd
       http://www.springframework.org/schema/aop
       http://www.springframework.org/schema/aop/spring-aop-4.0.xsd">
    
    <bean id="serviceImpl02"
          class="com.itheima.service.impl.UserServiceImpl02">
        
        <!--    构造方法参数    -->
        <constructor-arg
            name="paramUserDao"
            ref="userDao"
        >
        </constructor-arg>
        
        <constructor-arg
            name="paramValue"
            value="100.0"
        >
        </constructor-arg>
        
        <!--    setUserDao001方法参数    -->
        <property name="userDao001"
                  ref="userDao"
        >
        </property>
    </bean>
    
    <bean id="userDao"
          class="com.itheima.dao.impl.UserDaoImpl"
    >
    </bean>
</beans>

Test类

package com.itheima.service.impl;


import org.junit.jupiter.api.Test;
import org.springframework.context.support.ClassPathXmlApplicationContext;

import com.itheima.service.interfaces.InterfaceUserService;

import static org.junit.jupiter.api.Assertions.*;


/**
 * @copyright 2003-2025
 * @author    qiao wei
 * @date      2025-04-02
 * @version   1.0
 * @brief     
 * @history   name
 *            date
 *            brief
 */
class UserServiceImpl02Test {

    
    @Test
    public void test02() {
        ClassPathXmlApplicationContext applicationContext =
            new ClassPathXmlApplicationContext("./xml/service/userServiceImpl02.xml");

        InterfaceUserService userService =
            (InterfaceUserService) applicationContext.getBean("serviceImpl02");
//        userService.show();
    }
}

运行结果如下：