Spring带有依赖对象的Setter注入示例

1. 有依赖对象的Setter注入

像构造函数注入一样, 我们可以使用setter注入另一个bean的依赖项。在这种情况下, 我们使用property元素。在这里, 我们的方案是员工HAS-A地址。 Address类对象将称为从属对象。让我们首先看一下Address类：

Address.java

此类包含四个属性, 即setter和getter以及toString()方法。

package com.srcmini;

public class Address {
private String addressLine1, city, state, country;

//getters and setters

public String toString(){
	return addressLine1+" "+city+" "+state+" "+country;
}

Employee.java

它包含三个属性id, name和address(相关对象), 带有setInfo和getter的displayInfo()方法。

package com.srcmini;

public class Employee {
private int id;
private String name;
private Address address;

//setters and getters

void displayInfo(){
	System.out.println(id+" "+name);
	System.out.println(address);
}
}

applicationContext.xml

属性元素的ref属性用于定义另一个bean的引用。

<?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"
	xsi:schemaLocation="http://www.springframework.org/schema/beans 
http://www.springframework.org/schema/beans/spring-beans-3.0.xsd">

<bean id="address1" class="com.srcmini.Address">
<property name="addressLine1" value="51, Lohianagar"></property>
<property name="city" value="Ghaziabad"></property>
<property name="state" value="UP"></property>
<property name="country" value="India"></property>
</bean>

<bean id="obj" class="com.srcmini.Employee">
<property name="id" value="1"></property>
<property name="name" value="Sachin Yadav"></property>
<property name="address" ref="address1"></property>
</bean>

</beans>

Test.java

此类从applicationContext.xml文件获取Bean, 然后调用displayInfo()方法。

package com.srcmini;

import org.springframework.beans.factory.BeanFactory;
import org.springframework.beans.factory.xml.XmlBeanFactory;
import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;
import org.springframework.core.io.ClassPathResource;
import org.springframework.core.io.Resource;

public class Test {
public static void main(String[] args) {
	Resource r=new ClassPathResource("applicationContext.xml");
	BeanFactory factory=new XmlBeanFactory(r);
	
	Employee e=(Employee)factory.getBean("obj");
	e.displayInfo();
	
}
}

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