目錄
4 實現 WebMvcConfigurer 添加自定義攔截器
限流和限流算法已經介紹了常見的限流算法。guava 的 RateLimiter 使用的是令牌桶算法。本次實戰,我們用的是 guava 的RateLimiter,springboot 在處理請求時候,從桶中申請令牌,申請到了就成功響應,申請不到時直接返回失敗。
1 引入依賴
<dependency>
<groupId>com.google.guava</groupId>
<artifactId>guava</artifactId>
<version>18.0</version>
</dependency>
2 限流實現
package com.sb.rateLimiter.service;
import com.google.common.util.concurrent.RateLimiter;
import org.springframework.stereotype.Service;
@Service
public class RateLimiterService {
/**
* 每秒只發出5個令牌
*/
RateLimiter rateLimiter = RateLimiter.create(5.0);
/**
* 嘗試獲取令牌
* @return
*/
public boolean tryAcquire(){
return rateLimiter.tryAcquire();
}
}
3 自定義攔截器,在攔截器中實現限流
package com.sb.rateLimiter.interceptor;
import com.sb.rateLimiter.annotation.RateLimiterAnnotation;
import com.sb.rateLimiter.service.RateLimiterService;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.stereotype.Component;
import org.springframework.web.method.HandlerMethod;
import org.springframework.web.servlet.HandlerInterceptor;
import org.springframework.web.servlet.ModelAndView;
import javax.annotation.Resource;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
@Component
public class RateLimiterInterceptor implements HandlerInterceptor {
@Resource
private RateLimiterService accessLimitService;
private Logger logger = LoggerFactory.getLogger(RateLimiterInterceptor.class);
@Override
public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler) throws Exception {
if (!(handler instanceof HandlerMethod)) {
return true;
}
HandlerMethod handlerMethod = (HandlerMethod) handler;
RateLimiterAnnotation rateLimiterAnnotation = handlerMethod.getMethod().getAnnotation(RateLimiterAnnotation.class);
if(rateLimiterAnnotation == null) {
return true;
}
if (!accessLimitService.tryAcquire()) {
logger.info("限流中......");
return false;
}
logger.info("請求成功");
return true;
}
@Override
public void postHandle(HttpServletRequest request, HttpServletResponse response, Object handler, ModelAndView modelAndView) throws Exception {
}
@Override
public void afterCompletion(HttpServletRequest request, HttpServletResponse response, Object handler, Exception ex) throws Exception {
}
}
4 實現 WebMvcConfigurer 添加自定義攔截器
package com.sb.rateLimiter.config;
import com.sb.rateLimiter.interceptor.RateLimiterInterceptor;
import org.springframework.boot.SpringBootConfiguration;
import org.springframework.web.servlet.config.annotation.InterceptorRegistry;
import org.springframework.web.servlet.config.annotation.WebMvcConfigurer;
import javax.annotation.Resource;
@SpringBootConfiguration
public class WebConfiguration implements WebMvcConfigurer {
@Resource
private RateLimiterInterceptor rateLimiterInterceptor;
@Override
public void addInterceptors(InterceptorRegistry registry) {
registry.addInterceptor(rateLimiterInterceptor).addPathPatterns("/**");
}
}
5 RateLimiterAnnotation 實現
package com.sb.rateLimiter.annotation;
import java.lang.annotation.ElementType;
import java.lang.annotation.Retention;
import java.lang.annotation.RetentionPolicy;
import java.lang.annotation.Target;
@Retention(RetentionPolicy.RUNTIME)
@Target(ElementType.METHOD)
public @interface RateLimiterAnnotation {
int rateLimiterNumber() default 1;
}
6 Controller 類實現
package com.sb.rateLimiter.controller;
import com.sb.rateLimiter.annotation.RateLimiterAnnotation;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestMethod;
import org.springframework.web.bind.annotation.RestController;
@RestController
@RequestMapping("/api")
public class RateLimiterController {
@RateLimiterAnnotation
@RequestMapping(value = "/rateLimiterTest", method = RequestMethod.GET)
public void rateLimiterTest() throws Exception {
//業務邏輯;
}
}
7 通過 jmeter 進行限流測試