1、前言
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。
2、环境准备
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
3、上代码
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 key key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IP InetAddress 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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