SpringMVC 限流的示例代码

在使用SpringBoot做接口访问如何做接口的限流，这里我们可以使用google的Guava包来实现，当然我们也可以自己实现限流，Guava中的限流是久经考验的我们没必需重新再去写一个，如果想了解限流原理的同学可以自己查阅一下相关的资料，本文不作过来说明噢。

使用说明

在项目中引入Guava相关包

http://mvnrepository.com/artifact/com.google.guava/guava/21.0

maven项目

<!-- https://mvnrepository.com/artifact/com.google.guava/guava -->
<dependency>
 <groupId>com.google.guava</groupId>
 <artifactId>guava</artifactId>
 <version>21.0</version>
</dependency>

gradle项目

// https://mvnrepository.com/artifact/com.google.guava/guava
compile group: 'com.google.guava', name: 'guava', version: '21.0'

写一个SpringMVC的 *

SmoothBurstyInterceptor.java

import com.google.common.util.concurrent.RateLimiter;
import org.springframework.web.servlet.ModelAndView;
import org.springframework.web.servlet.handler.HandlerInterceptorAdapter;

import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.util.concurrent.TimeUnit;

public class SmoothBurstyInterceptor extends HandlerInterceptorAdapter {

public enum LimitType {
   DROP,//丢弃
   WAIT //等待
 }

/**
  * 限流器
  */
 private RateLimiter limiter;
 /**
  * 限流方式
  */
 private LimitType limitType = LimitType.DROP;

public SmoothBurstyInterceptor() {
   this.limiter = RateLimiter.create(10);
 }

/**
  * @param tps    限流量 (每秒处理量)
  * @param limitType 限流类型:等待/丢弃(达到限流量)
  */
 public SmoothBurstyInterceptor(int tps, SmoothBurstyInterceptor.LimitType limitType) {
   this.limiter = RateLimiter.create(tps);
   this.limitType = limitType;
 }
 /**
  * @param permitsPerSecond 每秒新增的令牌数
  * @param limitType 限流类型:等待/丢弃(达到限流量)
  */
 public SmoothBurstyInterceptor(double permitsPerSecond, SmoothBurstyInterceptor.LimitType limitType) {
   this.limiter = RateLimiter.create(permitsPerSecond, 1000, TimeUnit.MILLISECONDS);
   this.limitType = limitType;
 }

@Override
 public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler) throws Exception {
   if (limitType.equals(LimitType.DROP)) {
     if (limiter.tryAcquire()) {
       return super.preHandle(request, response, handler);
     }
   } else {
     limiter.acquire();
     return super.preHandle(request, response, handler);
   }
   throw new Exception("网络异常!");//达到限流后，往页面提示的错误信息。
 }

@Override
 public void postHandle(HttpServletRequest request, HttpServletResponse response, Object handler, ModelAndView modelAndView) throws Exception {
   super.postHandle(request, response, handler, modelAndView);
 }

@Override
 public void afterCompletion(HttpServletRequest request, HttpServletResponse response, Object handler, Exception ex) throws Exception {
   super.afterCompletion(request, response, handler, ex);
 }

public RateLimiter getLimiter() {
   return limiter;
 }

public void setLimiter(RateLimiter limiter) {
   this.limiter = limiter;
 }
}

SpringMVC拦截配置

WebConfig.java

@Component
public class WebConfig extends WebMvcConfigurerAdapter {

@Override
 public void addInterceptors(InterceptorRegistry registry) {
   // 多个 * 组成一个 * 链
   registry.addInterceptor(new SmoothBurstyInterceptor(100, SmoothBurstyInterceptor.LimitType.DROP)).addPathPatterns("/**");
   //限流可配置为SmoothBurstyInterceptor.LimitType.DROP丢弃请求或者SmoothBurstyInterceptor.LimitType.WAIT等待，100为每秒的速率
   super.addInterceptors(registry);
 }

}

来源：http://blog.csdn.net/dounine/article/details/71439809