第一步:創建SpringBoot項目,導入Maven依賴
<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:創建一個Aspect切面類並在其中定義好切點
@Aspect
@Component
public class WebControllerAop {
//匹配com.hc.controller包及其子包下的所有類的所有方法
@Pointcut("execution(public * com.hc.controller..*.*(..))")
public void executeService()
{
}
}
第三步:創建一個Controller請求處理類
@RestController
@RequestMapping("/aop")
public class WebController {
}
第四步:具體測試
前置通知:方法執行之前被調用
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(); //通知的簽名
System.out.println(signature.getName()); //代理的是哪一個方法
//獲取RequestAttributes
RequestAttributes requestAttributes = RequestContextHolder.getRequestAttributes();
//從獲取RequestAttributes中獲取HttpServletRequest的信息
HttpServletRequest request = (HttpServletRequest)
requestAttributes.resolveReference(RequestAttributes.REFERENCE_REQUEST);
Object[] obj = joinPoint.getArgs();//獲取目標方法的參數信息
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("請求的參數信息爲:"+str);
}
}
在Controller類裏添加一個請求處理方法來測試前面的前置通知,具體代碼如下:
@RequestMapping("/fun1")
public String fun1(@RequestParam Integer deptno, @RequestParam String dname, @RequestParam String loc) {
System.out.println(deptno + " " + dname + " " + loc);
return deptno + " " + dname + " " + loc;
}
啓動項目,然後在瀏覽器中請求http://localhost/aop/fun1?deptno=10&dname=sales&loc=boston時,結果如下圖所示:
後置返回通知:在方法正常返回結果之後執行
配置後置返回通知:
@AfterReturning(value = "execution(public * com.hc.controller..*.*(..))",returning = "keys")
public void doAfterReturningAdvice1(JoinPoint joinPoint,Object keys){
System.out.println("後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("後置返回通知的返回值:"+keys);
}
在Controller類裏添加請求處理方法來測試前面的後置返回通知:
@RequestMapping("/fun21")
public String fun21(String key){
return "key=: "+key;
}
@RequestMapping("/fun22")
public Integer fun22(Integer key){
return key;
}
啓動項目,然後在瀏覽器中請求http://localhost/aop/fun21?key=asdf 時,結果如下圖所示;請求時,結果如下圖所示:
後置異常通知:在方法拋出異常之後執行
配置後置異常通知:
@AfterThrowing(value = "executeService()",throwing = "exception")
public void doAfterThrowingAdvice(JoinPoint joinPoint,Throwable exception){
System.out.println("目標方法名:"+joinPoint.getSignature().getName());
if(exception instanceof NullPointerException){
System.out.println("發生了空指針異常!!!!!");
}
}
在Controller類裏添加請求處理方法來測試前面的後置返回通知,具體代碼如下:
@RequestMapping("/fun3")
public String fun3(String key){
throw new NullPointerException();
}
啓動項目,然後在瀏覽器中請求http://localhost/aop/fun3?key=asdf 時,結果如下圖所示:
後置最終通知:在方法執行之後執行
配置後置最終通知:
@After("executeService()")
public void doAfterAdvice(JoinPoint joinPoint){
System.out.println("後置通知執行了!!!!");
}
在Controller類裏添加請求處理方法來測試前面的後置返回通知,具體代碼如下:
@RequestMapping("/fun41")
public String fun41(String key){
throw new NullPointerException();
}
@RequestMapping("/fun42")
public String fun42(String key){
return key;
}
啓動項目,然後在瀏覽器中請求http://localhost/aop/fun41?key=asdf 時,結果如下圖所示;請求http://localhost/aop/fun44?key=asdf 是,結果如下圖所示:
環繞通知:圍繞着方法執行
配置環繞通知:
@Around("execution(public * com.hc.controller..*.fun*(..))")
public Object doAroundAdvice(ProceedingJoinPoint pjp){
Object res = null;
System.out.println("目標方法的名稱:"+pjp.getSignature().getName());
System.out.println("目標方法的參數:"+Arrays.toString(pjp.getArgs()));
try {
System.out.println("環繞通知--前置");
res = pjp.proceed();//調用目標方法
System.out.println("環繞通知--返回值:" + res);
} catch (Throwable throwable) {
System.out.println("環繞通知--異常");
throw new RuntimeException(throwable);
}
System.out.println("環繞通知--後置");
return res;
}
在Controller類裏添加請求處理方法來測試前面的後置返回通知,具體代碼如下:
@RequestMapping("/fun5")
public int fun5(int num1, int num2) {
return num1 + num2;
}
啓動項目,然後在瀏覽器中請求http://localhost/aop/fun5?num1=123&num2=321時,結果如下圖所示: