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SpringMVC 限流的示例代碼

更新時(shí)間：2017年12月01日 10:42:41 作者：dounine

這篇文章主要介紹了SpringMVC 限流的示例代碼，小編覺(jué)得挺不錯(cuò)的，現(xiàn)在分享給大家，也給大家做個(gè)參考。一起跟隨小編過(guò)來(lái)看看吧

在使用SpringBoot做接口訪問(wèn)如何做接口的限流，這里我們可以使用google的Guava包來(lái)實(shí)現(xiàn)，當(dāng)然我們也可以自己實(shí)現(xiàn)限流，Guava中的限流是久經(jīng)考驗(yàn)的我們沒(méi)必需重新再去寫一個(gè)，如果想了解限流原理的同學(xué)可以自己查閱一下相關(guān)的資料，本文不作過(guò)來(lái)說(shuō)明噢。

使用說(shuō)明

在項(xiàng)目中引入Guava相關(guān)包

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

maven項(xiàng)目

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

gradle項(xiàng)目

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

寫一個(gè)SpringMVC的攔截器

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,//丟棄
    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 (每秒處理量)
   * @param limitType 限流類型:等待/丟棄(達(dá)到限流量)
   */
  public SmoothBurstyInterceptor(int tps, SmoothBurstyInterceptor.LimitType limitType) {
    this.limiter = RateLimiter.create(tps);
    this.limitType = limitType;
  }
  /**
   * @param permitsPerSecond 每秒新增的令牌數(shù)
   * @param limitType 限流類型:等待/丟棄(達(dá)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("網(wǎng)絡(luò)異常!");//達(dá)到限流后，往頁(yè)面提示的錯(cuò)誤信息。
  }

  @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攔截配置

WebConfig.java

@Component
public class WebConfig extends WebMvcConfigurerAdapter {

  @Override
  public void addInterceptors(InterceptorRegistry registry) {
    // 多個(gè)攔截器組成一個(gè)攔截器鏈
    registry.addInterceptor(new SmoothBurstyInterceptor(100, SmoothBurstyInterceptor.LimitType.DROP)).addPathPatterns("/**");
    //限流可配置為SmoothBurstyInterceptor.LimitType.DROP丟棄請(qǐng)求或者SmoothBurstyInterceptor.LimitType.WAIT等待，100為每秒的速率
    super.addInterceptors(registry);
  }

}

以上就是本文的全部?jī)?nèi)容，希望對(duì)大家的學(xué)習(xí)有所幫助，也希望大家多多支持腳本之家。

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