学习spring(一)

我的第一个spring案例,使用构造参数方法进行属性注入,代码如下

实体类user:

public class User {
    private String username;

    public User(String username) {
        super();
        this.username = username;
    }

    public String getUsername() {
        return username;
    }
}

 

applicationContext.xml配置信息:

<?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:context="http://www.springframework.org/schema/context"
    xsi:schemaLocation="
http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd
http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context.xsd">
    <!-- 0、通过构造函数注入 （原始方式）
    <bean id="Di1" class="cn.bdqn.pojo.User">
        <constructor-arg value="admin"></constructor-arg>
    </bean>-->
    <!-- 1、根据构造器参数的类型注入
    <bean id="Di1" class="cn.bdqn.pojo.User">
        <constructor-arg type="java.lang.String" value="admin"></constructor-arg>
    </bean> -->
    <!-- 2、根据索引index注入 --> 
    <bean id="Di1" class="cn.bdqn.pojo.User">
        <constructor-arg index="0" value="admin"></constructor-arg>
    </bean>
</beans>

 

测试类:

import org.junit.Test;
import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;

import cn.bdqn.pojo.User;

public class TestDi {
    @Test
    public void show1(){
        ApplicationContext context = new ClassPathXmlApplicationContext("applicationContext.xml");
        User user = (User)context.getBean("Di1");
        System.out.println(user.getUsername());
    }
}

 

测试结果:

注入成功!