spring中的二种注入方式设值注入和构造注入简单例子

下面是一个spring注入的简单demo

建一个包为 com.lzyer.ouput下面接口

package com.lzyer.ouput;

public interface IOutputGenerator {

	public void generateOutput();
}

新建一个实现包com.lzyer.output.impl

package com.lzyer.ouput.impl;

import com.lzyer.ouput.IOutputGenerator;

public class CsvOutputGenerator implements IOutputGenerator{

	public void generateOutput() {
		
		System.out.println("This is csv ouputgenerator...");
	}

}

src下applicationContext.xml

<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" 
       xmlns:aop="http://www.springframework.org/schema/aop" 
       xmlns:context="http://www.springframework.org/schema/context"
       xmlns:jee="http://www.springframework.org/schema/jee"
       xmlns:tx="http://www.springframework.org/schema/tx" 
       xmlns:task="http://www.springframework.org/schema/task" 
       xsi:schemaLocation="http://www.springframework.org/schema/aop http://www.springframework.org/schema/aop/spring-aop-3.2.xsd http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-3.2.xsd http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context-3.2.xsd http://www.springframework.org/schema/jee http://www.springframework.org/schema/jee/spring-jee-3.2.xsd http://www.springframework.org/schema/tx http://www.springframework.org/schema/tx/spring-tx-3.2.xsd http://www.springframework.org/schema/task http://www.springframework.org/schema/task/spring-task-3.2.xsd">   
   <bean id="csv" class="com.lzyer.ouput.impl.CsvOutputGenerator"/>
   
   <!-- 
            设置注入 
   <bean id="helper" class="com.lzyer.ouput.test.OutputHelper">
       <property name="outputGenerator" ref="csv"></property>
   </bean>
   -->
   <!-- 构造注入 -->
   <bean id="helper" class="com.lzyer.ouput.test.OutputHelper">
      <constructor-arg>
         <ref bean="csv"/>
      </constructor-arg>
   </bean>
</beans>

新建一个包com.lzyer.ouput.test用来注入的类

package com.lzyer.ouput.test;

import com.lzyer.ouput.IOutputGenerator;

public class OutputHelper {

	IOutputGenerator outputGenerator;
	
	public void outputGenerator(){
		outputGenerator.generateOutput();
	}

	//构造注入
	public OutputHelper(IOutputGenerator outputGenerator){
		
		this.outputGenerator = outputGenerator;
	}
 /*	设置注入
  * public void setOutputGenerator(IOutputGenerator outputGenerator) {
		this.outputGenerator = outputGenerator;
	}
	*/
	
}

测试类

public class App {

	public static void main(String[] args) {
	  
		ApplicationContext context = new ClassPathXmlApplicationContext("applicationContext.xml");
		OutputHelper helper = (OutputHelper)context.getBean("helper");
		helper.outputGenerator();
	}
}

没有强制规定使用哪种注入方式，设置注入使用方便简单，所以用得比较多