springboot+redis 实现分布式限流令牌桶的示例代码

网上找了很多redis分布式限流方案，要不就是太大，需要引入第三方jar，而且还无法正常运行，要不就是定时任务定时往key中放入数据，使用的时候调用，严重影响性能，所以着手自定义实现redis令牌桶。只用到了spring-boot-starter-data-redis包，并且就几行代码。

a、idea新建springboot项目，引入spring-data-redis包b、编写令牌桶实现方法RedisLimitExcutorc、测试功能，创建全局拦截器，测试功能

maven添加依赖

<dependency> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-data-redis</artifactId></dependency>

令牌桶实现方法RedisLimitExcutor

package com.example.redis_limit_demo.config;import org.springframework.beans.factory.annotation.Autowired;import org.springframework.data.redis.core.StringRedisTemplate;import org.springframework.data.redis.core.script.DefaultRedisScript;import org.springframework.data.redis.core.script.RedisScript;import org.springframework.stereotype.Component;import java.util.ArrayList;import java.util.List;/** * 令牌桶实现 */@Componentpublic class RedisLimitExcutor { private StringRedisTemplate stringRedisTemplate; @Autowired public void setStringRedisTemplate(StringRedisTemplate stringRedisTemplate) {this.stringRedisTemplate = stringRedisTemplate; } /** * 令牌的 * * @param keykey值 * @param limitCount 容量 * @param seconds 时间间隔 * @return */ public boolean tryAccess(String key, int limitCount, int seconds) {String luaScript = buildLuaScript();RedisScript<Long> redisScript = new DefaultRedisScript<>(luaScript, Long.class);List<String> keys = new ArrayList<>();keys.add(key);Long count = stringRedisTemplate.execute(redisScript, keys, String.valueOf(limitCount), String.valueOf(seconds));if (count != 0) { return true;} else { return false;} } /** * 脚本 * * @return */ private static final String buildLuaScript() {StringBuilder lua = new StringBuilder();lua.append(' local key = KEYS[1]');lua.append('nlocal limit = tonumber(ARGV[1])');lua.append('nlocal curentLimit = tonumber(redis.call(’get’, key) or '0')');lua.append('nif curentLimit + 1 > limit then');lua.append('nreturn 0');lua.append('nelse');lua.append('n redis.call('INCRBY', key, 1)');lua.append('nredis.call('EXPIRE', key, ARGV[2])');lua.append('nreturn curentLimit + 1');lua.append('nend');return lua.toString(); }}

拦截器配置WebAppConfig

package com.example.redis_limit_demo.config;import org.springframework.context.annotation.Bean;import org.springframework.context.annotation.Configuration;import org.springframework.web.servlet.config.annotation.InterceptorRegistry;import org.springframework.web.servlet.config.annotation.WebMvcConfigurer;/** * 拦截器配置 */@Configurationpublic class WebAppConfig implements WebMvcConfigurer { @Override public void addInterceptors(InterceptorRegistry registry) {registry.addInterceptor(getRequestInterceptor()).addPathPatterns('/**'); } @Bean public RequestInterceptor getRequestInterceptor() {return new RequestInterceptor(); }}

拦截器实现RequestInterceptor

package com.example.redis_limit_demo.config;import org.springframework.beans.factory.annotation.Autowired;import org.springframework.context.annotation.Configuration;import org.springframework.web.servlet.HandlerInterceptor;import javax.servlet.http.HttpServletRequest;import javax.servlet.http.HttpServletResponse;import java.net.InetAddress;import java.net.UnknownHostException;/** * 拦截器实现 */@Configurationpublic class RequestInterceptor implements HandlerInterceptor { @Autowired private RedisLimitExcutor redisLimitExcutor; /** * 只有返回true才会继续向下执行，返回false取消当前请求 * * @param request * @param response * @param handler * @return */ @Override public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler) {/** * 根据实际情况设置QPS */String url = request.getRequestURI();String ip = getIpAdd(request);//QPS设置为5，手动刷新接口可以测试出来if (!redisLimitExcutor.tryAccess(ip+url, 5, 1)) { throw new RuntimeException('调用频繁');} else { return true;} } public static final String getIpAdd(HttpServletRequest request) {String ipAddress = request.getHeader('x-forwarded-for');if (ipAddress == null || ipAddress.length() == 0 || 'unknown'.equalsIgnoreCase(ipAddress)) { ipAddress = request.getHeader('Proxy-Client-IP');}if (ipAddress == null || ipAddress.length() == 0 || 'unknown'.equalsIgnoreCase(ipAddress)) { ipAddress = request.getHeader('WL-Proxy-Client-IP');}if (ipAddress == null || ipAddress.length() == 0 || 'unknown'.equalsIgnoreCase(ipAddress)) { ipAddress = request.getRemoteAddr(); if (ipAddress.equals('127.0.0.1') || ipAddress.equals('0:0:0:0:0:0:0:1')) {// 根据网卡取本机配置的IPInetAddress inet = null;try { inet = InetAddress.getLocalHost();} catch (UnknownHostException e) { return null;}ipAddress = inet.getHostAddress(); }}// 如果通过代理访问,可能获取2个IP,这时候去第二个(代理服务端IP)if (ipAddress.split(',').length > 1) { ipAddress = ipAddress.split(',')[1].trim();}return ipAddress; }}

测试controller

package com.example.redis_limit_demo.controller;import org.springframework.web.bind.annotation.RequestMapping;import org.springframework.web.bind.annotation.RestController;@RequestMapping('demo')@RestControllerpublic class DemoController { @RequestMapping('limit') public String demo() {//todo 写业务逻辑return 'aaaaa'; }}4、运行项目，访问接口

http://localhost:8080/demo/limit

当刷新频率高了以后，就会报错

5、码云地址（GitHub经常访问不到）

备注：

1、 redis的key可以根据实际情况设置，入例子中的ip+url，可以将全部流量进行控制，防止恶意刷接口，但需要注意的是，使用ip方式，要将QPS设置大一些，因为会出现整个大厦公用一个ip的情况。也可以使用url+userName，将QPS设置小一点，可以更加精准的限制api的访问。2、可以将抛出异常进行全局捕获和统一返回。

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