Spring使用Setter依賴注入

1. IOutputGenerator

package com.yiibai.output;
 
public interface IOutputGenerator
{
	public void generateOutput();
}

package com.yiibai.output.impl;

import com.yiibai.output.IOutputGenerator;

public class CsvOutputGenerator implements IOutputGenerator {
	public void generateOutput() {
		System.out.println("This is Csv Output Generator");
	}
}

2. Helper類

package com.yiibai.output;

import com.yiibai.output.IOutputGenerator;

public class OutputHelper {
	IOutputGenerator outputGenerator;

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

	//DI via setter method
	public void setOutputGenerator(IOutputGenerator outputGenerator) {
		this.outputGenerator = outputGenerator;
	}
}

3. Spring組態

在這種情況下，Spring將通過setter方法注入Bean 「CsvOutputGenerator」 到「OutputHelper」類，「setOutputGenerator(IOutputGenerator outputGenerator)」.

<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">

	<bean id="OutputHelper" class="com.yiibai.output.OutputHelper">
		<property name="outputGenerator" ref="CsvOutputGenerator" />
	</bean>
 
	<bean id="CsvOutputGenerator" class="com.yiibai.output.impl.CsvOutputGenerator" />

</beans>

4. 執行結果

package com.tw511.common;

import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;
import com.yiibai.output.OutputHelper;

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

輸出結果

This is Csv Output Generator