spring入门---------构造器注入

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使用构造器实现spring依赖注入

1.所需jar包

commons-logging-1.0.4.jar

spring.jar

2.实体类User.java

package entity;

public class User {

	private String name;
	private Integer age;
	private String sex;
	//构造器注入
	public User(String name, Integer age, String sex) {
		
		this.name = name;
		this.age = age;
		this.sex = sex;
	}
	//输出javabean的属性值方法
	public void printInfo() {
		System.out.println(name);
		System.out.println(age);
		System.out.println(sex);
	}
}

3.测试类Test.java

package main;

import org.springframework.beans.factory.BeanFactory;
import org.springframework.beans.factory.xml.XmlBeanFactory;
import org.springframework.core.io.ClassPathResource;
import org.springframework.core.io.Resource;

import entity.User;

public class Test {

	public static void main(String[] args) {
		// 导入配置文件
		Resource resource=new ClassPathResource("applicationContext.xml");
		//读取配置文件
		BeanFactory factory=new XmlBeanFactory(resource);
		//获取bean
		User user=(User)factory.getBean("user");//通过bean名来获取bean
		//调用printInfo方法
		user.printInfo();
		
	}

}

4.配置文件web.xml

<?xml version="1.0" encoding="UTF-8"?>
<web-app xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns="http://xmlns.jcp.org/xml/ns/javaee" xsi:schemaLocation="http://xmlns.jcp.org/xml/ns/javaee http://xmlns.jcp.org/xml/ns/javaee/web-app_3_1.xsd" id="WebApp_ID" version="3.1">
  <display-name>springConstructor</display-name>
  <welcome-file-list>
    <welcome-file>index.html</welcome-file>
    <welcome-file>index.htm</welcome-file>
    <welcome-file>index.jsp</welcome-file>
    <welcome-file>default.html</welcome-file>
    <welcome-file>default.htm</welcome-file>
    <welcome-file>default.jsp</welcome-file>
  </welcome-file-list>
</web-app>

5.applicationContext.xml

<?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-2.5.xsd">
	<!-- User Bean -->
	<bean name="user" class="entity.User">
		<!-- 配置构造器参数 -->
		<!-- 因为实体类User.java中的构造器有3个参数，所以要配置3次constructor-arg -->
		<!-- 当构造函数有多个参数时，可以使用constructor-arg
		  标签的index属性，index属性的值从0开始
		 -->
		 <!-- 
		   当构造器的参数需要用到另外的bean时，可以使用ref标签
		   <constructor-arg>
		   <ref bean="otherbean" >otherBean</ref>
		 </constructor-arg> 
		  -->
		 
		<constructor-arg  index="0">
			<value>小强</value>
		</constructor-arg>
		<constructor-arg  index="1">
			<value>26</value>
		</constructor-arg>
		<constructor-arg  index="2">
			<value>男</value>
		</constructor-arg>
	</bean>
</beans>

6.运行效果