SpringBoot基於RateLimiter+AOP動態的為不同介面限流
阿新 • • 發佈:2018-11-12
1.首先介面限流演算法:
1.計數器方式(傳統計數器缺點:臨界問題 可能違背定義固定速率原則)
2.令牌桶方式
3.漏桶方式
4.應用層限流(Nginx)
2.限流實現:
2.1. RateLimiter是guava提供的基於令牌桶演算法的實現類,可以非常簡單的完成限流特技,並且根據系統的實際情況來調整生成token的速率。
2.2.匯入相關依賴包
<dependency> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-web</artifactId> </dependency> <dependency> <groupId>org.aspectj</groupId> <artifactId>aspectjweaver</artifactId> </dependency> <dependency> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-test</artifactId> <scope>test</scope> </dependency> <dependency> <groupId>com.google.guava</groupId> <artifactId>guava</artifactId> <version>20.0</version> </dependency>
2.3.程式碼實現不多說每一步都有註解
2.3.1 定義註解
@Inherited
@Documented
@Target(ElementType.METHOD)
@Retention(RetentionPolicy.RUNTIME)
public @interface RateLimit {
double limitNum() default 20; //預設每秒放入桶中的token
}
2.3.2 封裝定義返回結果
public class MyResult { private Integer status; private String msg; private List<Object> data; public MyResult(Integer status, String msg, List<Object> data) { this.status = status; this.msg = msg; this.data = data; } public static MyResult OK(String msg, List<Object> data) { return new MyResult(200, msg, data); } public static MyResult Error(Integer status, String msg) { return new MyResult(status, msg, null); }
2.3.3 aop實現
-
@Component @Scope @Aspect public class RateLimitAspect { private Logger log = LoggerFactory.getLogger(this.getClass()); //用來存放不同介面的RateLimiter(key為介面名稱,value為RateLimiter) private ConcurrentHashMap<String, RateLimiter> map = new ConcurrentHashMap<>(); private static ObjectMapper objectMapper = new ObjectMapper(); private RateLimiter rateLimiter; @Autowired private HttpServletResponse response; @Pointcut("@annotation(com.icat.retalimitaop.annotation.RateLimit)") public void serviceLimit() { } @Around("serviceLimit()") public Object around(ProceedingJoinPoint joinPoint) throws NoSuchMethodException { Object obj = null; //獲取攔截的方法名 Signature sig = joinPoint.getSignature(); //獲取攔截的方法名 MethodSignature msig = (MethodSignature) sig; //返回被織入增加處理目標物件 Object target = joinPoint.getTarget(); //為了獲取註解資訊 Method currentMethod = target.getClass().getMethod(msig.getName(), msig.getParameterTypes()); //獲取註解資訊 RateLimit annotation = currentMethod.getAnnotation(RateLimit.class); double limitNum = annotation.limitNum(); //獲取註解每秒加入桶中的token String functionName = msig.getName(); // 註解所在方法名區分不同的限流策略 //獲取rateLimiter if(map.containsKey(functionName)){ rateLimiter = map.get(functionName); }else { map.put(functionName, RateLimiter.create(limitNum)); rateLimiter = map.get(functionName); } try { if (rateLimiter.tryAcquire()) { //執行方法 obj = joinPoint.proceed(); } else { //拒絕了請求(服務降級) String result = objectMapper.writeValueAsString(MyResult.Error(500, "系統繁忙!")); log.info("拒絕了請求:" + result); outErrorResult(result); } } catch (Throwable throwable) { throwable.printStackTrace(); } return obj; } //將結果返回 public void outErrorResult(String result) { response.setContentType("application/json;charset=UTF-8"); try (ServletOutputStream outputStream = response.getOutputStream()) { outputStream.write(result.getBytes("utf-8")); } catch (IOException e) { e.printStackTrace(); } } static { objectMapper.setSerializationInclusion(JsonInclude.Include.NON_NULL); } }
3.測試限流
2個介面設定沒秒限流5個和美妙限流10個
@RateLimit(limitNum = 5.0)
public MyResult getResults() {
log.info("呼叫了方法getResults");
return MyResult.OK("呼叫了方法", null);
}
@RateLimit(limitNum = 10.0)
public MyResult getResultTwo() {
log.info("呼叫了方法getResultTwo");
return MyResult.OK("呼叫了方法getResultTwo", null);
}
使用Jmeter測試getResults介面 20個併發(設定每秒只能處理5個請求)
使用Jmeter測試getResultTwo介面 20個併發(設定每秒只能處理10個請求)
結果會比設定的多一個(百度了很久沒找到原因 - -! )
下載地址:
連結:https://pan.baidu.com/s/1yUr0-QxQoMD_XRPivuUjZw 提取碼:6w3e
第一次寫部落格有錯誤請輕噴!!!!!!