Spring通过构造方法依赖注入
1. 创建一个Person
package com.spring.bean; public class Person { private String name; private String address; private double height; private int weight; public Person(String name, String address, double height) { super(); this.name = name; this.address = address; this.height = height; } public Person(String name, String address, int weight) { super(); this.name = name; this.address = address; this.weight = weight; } @Override public String toString() { return "Person [name=" + name + ", address=" + address + ", height=" + height + ", weight=" + weight + "]"; } }
2. 创建spring 配制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.xsd"> <!-- 通过构造器注入属性--> <!-- 1. 通过index属性指定要注入的属性值,默认会选择靠前的构造器注入 --> <bean id="person1" name="person" class="com.spring.bean.Person"> <constructor-arg value="matt" index="0"></constructor-arg> <constructor-arg value="上海" index="1"></constructor-arg> <constructor-arg value="172" index="2"></constructor-arg> </bean> <!-- 2. 通过name属性指定要注入的属性值--> <bean id="person2" class="com.spring.bean.Person"> <constructor-arg value="joy" index="0"></constructor-arg> <constructor-arg value="上海" index="1"></constructor-arg> <constructor-arg value="59" name="weight"></constructor-arg> </bean> <!-- 2. 通过type属性指定要注入的属性值--> <bean id="person3" class="com.spring.bean.Person"> <constructor-arg value="joy" index="0"></constructor-arg> <constructor-arg value="上海" index="1"></constructor-arg> <constructor-arg value="59" type="int"></constructor-arg> </bean> </beans>
3. 创建运行类
package com.spring.bean; import org.springframework.context.ApplicationContext; import org.springframework.context.support.ClassPathXmlApplicationContext; public class PersonMain { public static void main(String[] args) { ApplicationContext ctx = new ClassPathXmlApplicationContext("applicationContext.xml"); Person person1 = (Person) ctx.getBean("person1"); System.out.println(person1); Person person2 = (Person) ctx.getBean("person2"); System.out.println(person2); Person person3 = (Person) ctx.getBean("person3"); System.out.println(person3); } }
运行结果:
Person [name=matt, address=上海, height=172.0, weight=0] Person [name=joy, address=上海, height=0.0, weight=59] Person [name=joy, address=上海, height=0.0, weight=59]
注, 可以通过spring配制文件中不同的属性指定选择相应的构造方法。