spring注解@Resource为什么不起作用？

时间：2016-07-31 19:03:56 阅读：721 评论：0 收藏：0 [点我收藏+]

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我想要使用注解的方式，在service层调用dao层查询数据库的方法，查询卡号“1”是否存在，可是报错：

技术分享这应该注解使用不成功的意思，spring注解应该怎么使用呢？

这里有个完整的例子，项目结构如下

技术分享

TestAnnotation.java

import org.springframework.context.ApplicationContext;  
import org.springframework.context.support.ClassPathXmlApplicationContext;  
  
  
public class TestAnnotation {  
    public static void main(String[] args) {  
        ApplicationContext context = new ClassPathXmlApplicationContext("applicationContext.xml");  
        MyAction action = (MyAction)context.getBean("myAction");  
        action.testAnnotation();  
          
    }  
}

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"
     xmlns:p="http://www.springframework.org/schema/p"
    xsi:schemaLocation="http://www.springframework.org/schema/beans 
    http://www.springframework.org/schema/beans/spring-beans-3.1.xsd
        http://www.springframework.org/schema/context    
    http://www.springframework.org/schema/context/spring-context-3.1.xsd">

    <context:annotation-config/>    
    <!-- action暂未用注解 -->    
    <bean id="myAction" class="com.demo.annotation.MyAction" scope="prototype" />  
      
    <!-- 注解测试   -->  
    <context:component-scan base-package="com.demo.annotation" />  

</beans>

MyAction.java

import javax.annotation.Resource;  

public class MyAction{  
    @Resource(name="testService")  
    private TestService testService;  
   
    public String testAnnotation(){  
        if(null == testService){  
            System.out.println("Service is null!!");  
        }  
        String result = testService.getTestAnnotation();  
        System.out.println(result);  
        return "success";  
    }  
      
    public TestService getTestService() {  
        return testService;  
    }  
  
    public void setTestService(TestService testService) {  
        this.testService = testService;  
    }  
      
}

TestService.java

public interface TestService {
    public String getTestAnnotation();  
}

TestServiceImpl.java

import org.springframework.stereotype.Service;  

import org.springframework.beans.factory.annotation.Autowired;  
import org.springframework.beans.factory.annotation.Qualifier;  
  
  
  
/** 
 *  
 * 注解测试 
 * 
 */  
  
@Service("testService")  
public class TestServiceImp implements TestService {  
    /** 
     * 自动装配 
     */  
    @Autowired  
    @Qualifier("testDao")  
    //@Resource(name="testDao"), 等价于<property ………… ref="testDao" />   
    private TestDao testDao;  
  
    public TestDao getTestDao() {  
        return testDao;  
    }  
  
    public void setTestDao(TestDao testDao) {  
        this.testDao = testDao;  
    }  
  
  
    @Override  
    public String getTestAnnotation() {  
        // TODO Auto-generated method stub  
        return testDao.getTestDaoAnnotation();  
    }  
  
}

TestDao.java

public interface TestDao {  
    /** 
     * 得到dao层注解 
     * @return 
     */  
    public String getTestDaoAnnotation();  
}

TestDaoImpl.java