技術標籤：javaaopspringpythonredis

一、依賴

 1 <dependency>
 2     <groupId>org.springframework.boot</groupId>
 3     <artifactId>spring-boot-starter-web</artifactId>
 4 </dependency>
 5 
 6 <!-- aop -->
 7 <dependency>
 8     <groupId>org.springframework.boot</groupId>
 9     <artifactId>spring-boot-starter-aop</artifactId>
10 </dependency>
 

二、註解

 1 @Target(ElementType.METHOD)
 2 @Retention(RetentionPolicy.RUNTIME)
 3 @Documented
 4 public @interface Limiter {
 5     /**
 6      * 使用spel表示式獲取限流的key
 7      * @return
 8      */
 9     String value();
10 }

三、AOP切面的應用

 1 @Aspect
 2 @Component
 3 public class LimiterAspect {
 4     private ExpressionParser parser = new SpelExpressionParser();
 5     private LocalVariableTableParameterNameDiscoverer discoverer = new LocalVariableTableParameterNameDiscoverer();
 6 
 7     @Pointcut("@annotation(limiter)")
 8     public void pointcut(Limiter limiter) {
 9     }
10 
11     @Around("pointcut(limiter)")
12     public Object around(ProceedingJoinPoint pjp, Limiter limiter) throws Throwable {
13         Method method = this.getMethod(pjp);
14         String methodName = method.toString();
15 
16         //獲取方法的引數值
17         Object[] args = pjp.getArgs();
18         EvaluationContext context = this.bindParam(method, args);
19 
20         //根據spel表示式獲取值
21         Expression expression = parser.parseExpression(limiter.value());
22         Object key = expression.getValue(context);
23         //列印
24         System.out.println(key);
25         
26         return pjp.proceed();
27     }
28 
29     /**
30      * 獲取當前執行的方法
31      *
32      * @param pjp
33      * @return
34      * @throws NoSuchMethodException
35      */
36     private Method getMethod(ProceedingJoinPoint pjp) throws NoSuchMethodException {
37         MethodSignature methodSignature = (MethodSignature) pjp.getSignature();
38         Method method = methodSignature.getMethod();
39         Method targetMethod = pjp.getTarget().getClass().getMethod(method.getName(), method.getParameterTypes());
40         return targetMethod;
41     }
42 
43     /**
44      * 將方法的引數名和引數值繫結
45      *
46      * @param method 方法，根據方法獲取引數名
47      * @param args   方法的引數值
48      * @return
49      */
50     private EvaluationContext bindParam(Method method, Object[] args) {
51         //獲取方法的引數名
52         String[] params = discoverer.getParameterNames(method);
53 
54         //將引數名與引數值對應起來
55         EvaluationContext context = new StandardEvaluationContext();
56         for (int len = 0; len < params.length; len++) {
57             context.setVariable(params[len], args[len]);
58         }
59         return context;
60     }
 

四、Controller

 1 @RestController
 2 public class TestController {
 3 
 4     //獲取名為id的引數
 5     @Limiter("#id")
 6     @GetMapping("test")
 7     public String test(Long id){
 8         return "hello";
 9     }
10 }

五、獲取物件(補充)

1、註解

1 @Limter(value = "#testObj")
2 public JSONObject test01(TestObj  testObj){
3       // ......      
4 }
 

多個切點同時獲取

 1 /**
 2  * 設定操作日誌切入點 記錄操作日誌 在註解的位置切入程式碼
 3  */
 4 //@Pointcut("@annotation(com.test.Limter)")
 5 @Pointcut("@annotation(limter)")
 6 public void operLogPointCut(Limter limter) {
 7 }
 8 
 9 @Pointcut("execution(public * com.test.aaa..*.*(..))")
10 public void operLogPointMethod() {
11 }

執行緒變數的使用，當前切面類中使用執行緒變數儲存變數

 1 @Aspect
 2 @Component
 3 public class LogAspect {
 4 
 5     @Autowired
 6     private LogsService logsService;
 7     // 執行緒變數
 8     private ThreadLocal<String> threadLocal = new ThreadLocal<>();
 9 
10     /**
11      * 設定操作日誌切入點 記錄操作日誌 在註解的位置切入程式碼
12      */

方法體中存入資料

public void savaData(){
    threadLocal.set("asdf");
}

在另一個方法體中獲取當前執行緒資料

public void savaData(){
    String value = threadLocal.get();
}

切點多條件限制 &&

 1 @AfterReturning(value = "operLogPointCut(limter) && operLogPointMethod()", returning = "returnValue")
 2     public void saveOperLog(JoinPoint joinPoint, Limter limter, Object returnValue) {
 3         Object[] args = joinPoint.getArgs();
 4         // 從切面織入點處通過反射機制獲取織入點處的方法
 5         MethodSignature signature = (MethodSignature) joinPoint.getSignature();
 6         // 獲取切入點所在的方法
 7         Method method = signature.getMethod();
 8         EvaluationContext context = this.bindParam(method, args);
 9         Expression expression = parser.parseExpression(limter.value());
10 
11         TestObj testObj= expression.getValue(context, TestObj.class);
12         // ......
13         new Thread(() -> logsService.saveLogs(Obj...)).start();
14 
15         // 存入資料庫後移除當前執行緒變數
16         threadLocal.remove();
17     }

參考：

https://blog.csdn.net/weixin_45052750/article/details/105742934

其他參考：

https://www.codeleading.com/article/30952452765/