Spring中AOP实例详解
需要增强的服务
假如有以下service，他的功能很简单，打印输入的参数并返回参数。
@Service
public class SimpleService {
public String getName(String name) {
System.out.println(get name is: + name);
return name;
}
}
定义切面和切点
@Component
@Aspect
public class L
ogAspect {
// 定义切点
@Pointcut(within(com.ydoing.service..*))
// @Pointcut(execution(* com.ydoing.service.*.*(..)))
public void pointCut() {
}
}
Before增强处理
// 定义Before增强处理
// 在目标方法调用之前执行增强处理
@Before(pointCut())
public void before(JoinPoint jp) {
// 获取连接点传入参数
// Object args = jp.getArgs();
System.out.println(Before增强处理--execute before target method call);
}
--------------------------------------------------------------------------------
测试输出：
Before增强处理--execute before target method call
get name is: Bob
AfterReturning增强
// 在目标方法调用之后执行增强处理
@AfterReturning(pointcut = pointCut(), returning = ret)
public void afterReturning(JoinPoint jp, Object ret) {
System.out.println(AfterReturnin增强处理--execute after target method call, return value is ： + ret);
}
--------------------------------------------------------------------------------
测试输出：
get name is: Bob
AfterReturnin增强处理--execute after target method call, return value is ：Bob
Around增强
@Around(pointCut())
public void around(ProceedingJoinPoint jp) {
System.out.println(Around增强--around start...);
Object[] args = jp.getArgs();
// 修改目标方法传入的参数
args[0] = around_add_ + args[0];
try {
System.out.println(修改传入参数后执行输出：);
jp.proceed(args);
} catch (Throwable e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
System.out.println(Around增强--around end);
}
--------------------------------------------------------------------------------
输出：
Around增强--around start...
修改传入参数后执行输出：
get name is: around_add_Bob
Around增强--around end
After增强
// 无论是否发生异常都会 处理
@After(pointCut())
public void after() {
System.out.println(After增强--always do no matter what happen);
}
--------------------------------------------------------------------------------
输出：
get name is: Bob
After增强--always do no matter what happen
AfterThrowing增强
@AfterThrowing(pointcut = pointCut(), throwing = ex)
public void afterThrowing(JoinPoint jp, Throwable ex) {
System.out.println(error is: + ex);
}
这里没抛异常，就没有输出了
测试代码如下
@Configuration
@EnableAspectJAutoProxy
@ComponentScan(basePackages = com.ydoing.service,com.ydoing.aspect)
public class AppConfig {
public static void main(String[] args) {
@SuppressWarnings(resource)
ApplicationContext ctx = new AnnotationConfigApplicationContext(AppConfig.class);
SimpleService service = ctx.getBean(SimpleService.class);
service.getName(Bob);
}
}