第一步:创建SpringBoot项目,导入Maven依赖
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-web</artifactId>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-test</artifactId>
<scope>test</scope>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-aop</artifactId>
</dependency>
<dependency>
<groupId>javax.servlet</groupId>
<artifactId>javax.servlet-api</artifactId>
<version>4.0.1</version>
</dependency>
第二步:创建一个Aspect切面类并在其中定义好切点
@Aspect
@Component
public class WebControllerAop {
//匹配com.hc.controller包及其子包下的所有类的所有方法
@Pointcut("execution(public * com.hc.controller..*.*(..))")
public void executeService()
{
}
}
第三步:创建一个Controller请求处理类
@RestController
@RequestMapping("/aop")
public class WebController {
}
第四步:具体测试
前置通知:方法执行之前被调用
配置前置通知:
@Before("executeService()")
public void doBeforeAdvice(JoinPoint joinPoint) throws JsonProcessingException {
System.out.println("前置通知!!!");
Signature signature = joinPoint.getSignature(); //通知的签名
System.out.println(signature.getName()); //代理的是哪一个方法
//获取RequestAttributes
RequestAttributes requestAttributes = RequestContextHolder.getRequestAttributes();
//从获取RequestAttributes中获取HttpServletRequest的信息
HttpServletRequest request = (HttpServletRequest)
requestAttributes.resolveReference(RequestAttributes.REFERENCE_REQUEST);
Object[] obj = joinPoint.getArgs();//获取目标方法的参数信息
System.out.println(Arrays.toString(obj));
if(obj.length > 0) {
Enumeration<String> enumeration = request.getParameterNames();
Map<String,String> parameterMap = new HashMap();
while (enumeration.hasMoreElements()){
String parameter = enumeration.nextElement();
parameterMap.put(parameter,request.getParameter(parameter));
}
ObjectMapper om = new ObjectMapper();
String str = om.writeValueAsString(parameterMap);
System.out.println("请求的参数信息为:"+str);
}
}
在Controller类里添加一个请求处理方法来测试前面的前置通知,具体代码如下:
@RequestMapping("/fun1")
public String fun1(@RequestParam Integer deptno, @RequestParam String dname, @RequestParam String loc) {
System.out.println(deptno + " " + dname + " " + loc);
return deptno + " " + dname + " " + loc;
}
启动项目,然后在浏览器中请求http://localhost/aop/fun1?deptno=10&dname=sales&loc=boston时,结果如下图所示:
后置返回通知:在方法正常返回结果之后执行
配置后置返回通知:
@AfterReturning(value = "execution(public * com.hc.controller..*.*(..))",returning = "keys")
public void doAfterReturningAdvice1(JoinPoint joinPoint,Object keys){
System.out.println("后置返回通知的返回值:"+keys);
}
@AfterReturning(value = "execution(public * com.hc.controller..*.*(..))",returning = "keys",argNames = "keys")
public void doAfterReturningAdvice2(String keys){
System.out.println("后置返回通知的返回值:"+keys);
}
在Controller类里添加请求处理方法来测试前面的后置返回通知:
@RequestMapping("/fun21")
public String fun21(String key){
return "key=: "+key;
}
@RequestMapping("/fun22")
public Integer fun22(Integer key){
return key;
}
启动项目,然后在浏览器中请求http://localhost/aop/fun21?key=asdf 时,结果如下图所示;请求时,结果如下图所示:
后置异常通知:在方法抛出异常之后执行
配置后置异常通知:
@AfterThrowing(value = "executeService()",throwing = "exception")
public void doAfterThrowingAdvice(JoinPoint joinPoint,Throwable exception){
System.out.println("目标方法名:"+joinPoint.getSignature().getName());
if(exception instanceof NullPointerException){
System.out.println("发生了空指针异常!!!!!");
}
}
在Controller类里添加请求处理方法来测试前面的后置返回通知,具体代码如下:
@RequestMapping("/fun3")
public String fun3(String key){
throw new NullPointerException();
}
启动项目,然后在浏览器中请求http://localhost/aop/fun3?key=asdf 时,结果如下图所示:
后置最终通知:在方法执行之后执行
配置后置最终通知:
@After("executeService()")
public void doAfterAdvice(JoinPoint joinPoint){
System.out.println("后置通知执行了!!!!");
}
在Controller类里添加请求处理方法来测试前面的后置返回通知,具体代码如下:
@RequestMapping("/fun41")
public String fun41(String key){
throw new NullPointerException();
}
@RequestMapping("/fun42")
public String fun42(String key){
return key;
}
启动项目,然后在浏览器中请求http://localhost/aop/fun41?key=asdf 时,结果如下图所示;请求http://localhost/aop/fun44?key=asdf 是,结果如下图所示:
环绕通知:围绕着方法执行
配置环绕通知:
@Around("execution(public * com.hc.controller..*.fun*(..))")
public Object doAroundAdvice(ProceedingJoinPoint pjp){
Object res = null;
System.out.println("目标方法的名称:"+pjp.getSignature().getName());
System.out.println("目标方法的参数:"+Arrays.toString(pjp.getArgs()));
try {
System.out.println("环绕通知--前置");
res = pjp.proceed();//调用目标方法
System.out.println("环绕通知--返回值:" + res);
} catch (Throwable throwable) {
System.out.println("环绕通知--异常");
throw new RuntimeException(throwable);
}
System.out.println("环绕通知--后置");
return res;
}
在Controller类里添加请求处理方法来测试前面的后置返回通知,具体代码如下:
@RequestMapping("/fun5")
public int fun5(int num1, int num2) {
return num1 + num2;
}
启动项目,然后在浏览器中请求http://localhost/aop/fun5?num1=123&num2=321时,结果如下图所示: