11_注解03_用注解方式决定接口的实现类

【工程截图】

【Document.java】

package com.HigginCui.document.annotation;

public interface Document {
    public void readDocument();
    public void writeDocument();
}

【ExcelDocument.java】

package com.HigginCui.document.annotation;

import org.springframework.stereotype.Component;

@Component("excelDocument")
public class ExcelDocument implements Document{
    @Override
    public void readDocument() {
        System.out.println("Excel read....");
    }
    @Override
    public void writeDocument() {
        System.out.println("Excel write....");
    }
}

【PdfDocument.java】

package com.HigginCui.document.annotation;

import org.springframework.stereotype.Component;

@Component("pdfDocument")
public class PdfDocument implements Document{
    @Override
    public void readDocument() {
        System.out.println("Pdf read....");
    }
    @Override
    public void writeDocument() {
        System.out.println("Pdf write....");
    }
}

【WordDocument.java】

package com.HigginCui.document.annotation;

import org.springframework.stereotype.Component;

@Component("wordDocument")
public class WordDocument implements Document{
    @Override
    public void readDocument() {
        System.out.println("Word read....");
    }
    @Override
    public void writeDocument() {
        System.out.println("Word write....");
    }
}

【DocumentManager.java】

package com.HigginCui.document.annotation;

import javax.annotation.Resource;

import org.springframework.stereotype.Component;

@Component("documentManager")
public class DocumentManager {

    @Resource(name="excelDocument")
    private Document document;
    
    public void read(){
        this.document.readDocument();
    }
    public void write(){
        this.document.writeDocument();
    }
}

【applicationContext.xml】

<?xml version= "1.0" encoding ="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
        xmlns:context="http://www.springframework.org/schema/context"
       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
           http://www.springframework.org/schema/context
           http://www.springframework.org/schema/context/spring-context-2.5.xsd">

    <!-- 把一个类放入到Spring容器中，该类就是一个component，此时不需要声明对应的bean -->
    <context:component-scan base-package="com.HigginCui.document.annotation"></context:component-scan>
</beans>

【testDocument.java】

package com.HigginCui.test;

import org.junit.Test;
import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;

import com.HigginCui.document.annotation.DocumentManager;


public class testDocument {
    @Test
    public void test(){
        ApplicationContext context=new ClassPathXmlApplicationContext("applicationContext.xml");
        DocumentManager documentManager=(DocumentManager) context.getBean("documentManager");
        documentManager.write();
        documentManager.read();
    }
}

【运行结果】

Excel write....
Excel read....