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spring：实例化类过程中方法执行顺序。

news 来源：原创 2025/6/7 8:18:19

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);}@Overridepublic void afterPropertiesSet() throws Exception {System.out.println("实现接口InitializingBean的方法afterPropertiesSet");}@Overridepublic 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);}@Overridepublic 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.xsdhttp://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context-4.0.xsdhttp://www.springframework.org/schema/tx http://www.springframework.org/schema/tx/spring-tx-4.0.xsdhttp://www.springframework.org/schema/aophttp://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-argname="paramUserDao"ref="userDao"></constructor-arg><constructor-argname="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 {@Testpublic void test02() {ClassPathXmlApplicationContext applicationContext =new ClassPathXmlApplicationContext("./xml/service/userServiceImpl02.xml");InterfaceUserService userService =(InterfaceUserService) applicationContext.getBean("serviceImpl02");
//        userService.show();}
}

运行结果如下：