SpringMVC 限流的示例代码

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ptAaph目中引入Guava相关包

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

maven项目

com.google.guava

guava

21.0

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的拦截器

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,//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) {

// 多个拦截器组成一个拦截器链

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);

}

}

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