Spring系列【03】应用构造器注入法实现Bean的注入

package cn.com.xf;

public class User {
    private String name;
    private int age;
    private String remark;
    
        //省略setter/getter方法

    @Override
    public String toString() {
        return "User [name=" + name + ", age=" + age + ", remark=" + remark
                + "]";
    }

}

package cn.com.xf;

public class UserUtil {
    private User user;
    public User getUser() {
        return user;
    }
        
        //注意这个构造方法
    public UserUtil(User u){
        this.user=u;
    }
    
    public boolean isUser() {
        if (user != null) {
            return true;
        } else {
            return false;
        }
    }

}

以下是Spring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"
    xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-2.0.xsd">

    <bean id="user" class="cn.com.xf.User">
        <property name="name" value="jikoy"></property>
        <property name="age" value="28"></property>
        <property name="remark" value="this is remark"></property>
    </bean>
    <bean id="userUtil" class="cn.com.xf.UserUtil">
        <constructor-arg ref="user"></constructor-arg>
    </bean>
</beans>

以上，我跟前一篇不一样，没有使用P标签，但效果是一样的，注意 <constructor-arg ref="user"></constructor-arg>

package cn.com.xf;

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

public class Test {

    public static void main(String[] args) {
        ConfigurableApplicationContext ctx=new ClassPathXmlApplicationContext("applicationContext.xml");
        User user=(User) ctx.getBean("user");
        ctx.close();
        System.out.println(user);
    }

}

测试类仍是使用了ApplicationContext的子接口方法，并提供了关闭方法。