【Java】关于Spring框架的总结 （三）

 1 import java.lang.annotation.ElementType;  
 2 import java.lang.annotation.Retention;  
 3 import java.lang.annotation.RetentionPolicy;  
 4 import java.lang.annotation.Target;  
 5   
 6 // 在运行时执行  
 7 @Retention(RetentionPolicy.RUNTIME)  
 8 // 注解适用地方(字段和方法)  
 9 @Target({ ElementType.FIELD, ElementType.METHOD })  
10 public @interface AnnotationTest {  
11   
12     // 注解的name属性  
13     public String name() default "";  
14 }  

import org.springframework.stereotype.Component;
import org.springframework.stereotype.Repository;

// 通过注解定义一个DAO
@Component("userDao")
public class UserDaoImpl implements IUserDao {

    @Override
    public void addUser(User user) {
        // 这里并未实现完整数据库操作，仅为说明问题
        System.out.println("add user");
    }

}

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.beans.factory.annotation.Qualifier;
import org.springframework.stereotype.Service;

@Service("userService")
public class UserServiceImpl implements IUserService {
    
    // 声明接口类型的引用和具体实现类解耦合
    @Autowired
    @Qualifier("userDao")
    private IUserDao dao;
    
    @Override
    public void addUser(User user) {
        dao.addUser(user);
    }
}

import javax.annotation.Resource;
import org.springframework.stereotype.Service;

@Service("userService")
public class UserServiceImpl implements IUserService {

    // 查找名为 dao 的 Bean，并注入给 dao 属性
   @Resource(name = "userDao")
   private IUserDao dao;

    @Override
    public void addUser(User user) {
        dao.addUser(user);        
    }

}

 1 <?xml version="1.0" encoding="UTF-8"?>
 2 <beans xmlns="http://www.springframework.org/schema/beans"
 3     xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
 4     xmlns:context="http://www.springframework.org/schema/context"
 5     xmlns:aop="http://www.springframework.org/schema/aop"
 6     xsi:schemaLocation="http://www.springframework.org/schema/beans
 7         http://www.springframework.org/schema/beans/spring-beans.xsd
 8         http://www.springframework.org/schema/context
 9         http://www.springframework.org/schema/context/spring-context-4.2.xsd
10         http://www.springframework.org/schema/aop 
11         http://www.springframework.org/schema/aop/spring-aop-4.2.xsd">
12 
13 </beans>

 1 import org.apache.log4j.Logger;
 2 import org.aspectj.lang.JoinPoint;
 3 import org.aspectj.lang.ProceedingJoinPoint;
 4 import org.aspectj.lang.annotation.AfterReturning;
 5 import org.aspectj.lang.annotation.AfterThrowing;
 6 import org.aspectj.lang.annotation.Around;
 7 import org.aspectj.lang.annotation.Aspect;
 8 import org.aspectj.lang.annotation.Pointcut;
 9 import org.springframework.stereotype.Component;
10 
11 @Aspect
12 @Component("serviceAdviceLogging")
13 public class ServiceAdviceLogging {
14     private Logger logger = Logger.getLogger(ServiceAdviceLogging.class);
15     
16     // 注解定义切点 参数为定义切点的表达式部分
17     @Pointcut("execution(* cn.zdpz.service..*.*(..))")
18     public void pointcutLogging(){}
19     
20     // 注解实现后置增强
21     @AfterReturning("pointcutLogging()")
22     public void afterReturning(JoinPoint joinPoint){
23         String simpleClassName = joinPoint.getSignature().getName();
24         String methodName = joinPoint.getTarget().getClass().getName();
25         logger.info(simpleClassName+"-----"+methodName+"后置增强方法");
26     }
27     
28     // 注解实现异常增强
29     @AfterThrowing(pointcut="pointcutLogging()",throwing="e")
30     public void afterThrowing(JoinPoint joinPoint,Exception e){
31         String simpleClassName = joinPoint.getSignature().getName();
32         String methodName = joinPoint.getTarget().getClass().getName();
33         logger.info(simpleClassName+"-----"+methodName+"出现异常:"+e.getMessage());
34     }
35     
36     // 注解实现环绕增强
37     @Around("pointcutLogging()")
38     public Object around(ProceedingJoinPoint proceedingJoinPoint){
39　　　　　 Object obj = null;
40         try {
41             System.out.println("环绕增强前：");
42             obj = proceedingJoinPoint.proceed();
43             System.out.println("环绕增强后：");
44         } catch (Throwable e) {
45             e.printStackTrace();
46         }
47　　　　　 return obj;
48     }
49 }

<!-- 自动扫描指定包及其子包下的所有Bean类 -->
<context:component-scan base-package="org.springframework.*"/>

<!-- 自动为切面方法中匹配的方法所在的类生成代理对象。 -->
<aop:aspectj-autoproxy />