springboot+redis 實現分布式限流令牌桶的示例代碼
網上找了很多redis分布式限流方案,要不就是太大,需要引入第三方jar,而且還無法正常運行,要不就是定時任務定時往key中放入數據,使用的時候調用,嚴重影響性能,所以著手自定義實現redis令牌桶。只用到了spring-boot-starter-data-redis包,并且就幾行代碼。
2、環境準備a、idea新建springboot項目,引入spring-data-redis包b、編寫令牌桶實現方法RedisLimitExcutorc、測試功能,創建全局攔截器,測試功能
3、上代碼maven添加依賴
<dependency> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-data-redis</artifactId></dependency>
令牌桶實現方法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;/** * 令牌桶實現 */@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 時間間隔 * @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;} } /** * 腳本 * * @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(); }}
攔截器配置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;/** * 攔截器配置 */@Configurationpublic class WebAppConfig implements WebMvcConfigurer { @Override public void addInterceptors(InterceptorRegistry registry) {registry.addInterceptor(getRequestInterceptor()).addPathPatterns('/**'); } @Bean public RequestInterceptor getRequestInterceptor() {return new RequestInterceptor(); }}
攔截器實現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;/** * 攔截器實現 */@Configurationpublic class RequestInterceptor implements HandlerInterceptor { @Autowired private RedisLimitExcutor redisLimitExcutor; /** * 只有返回true才會繼續向下執行,返回false取消當前請求 * * @param request * @param response * @param handler * @return */ @Override public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler) {/** * 根據實際情況設置QPS */String url = request.getRequestURI();String ip = getIpAdd(request);//QPS設置為5,手動刷新接口可以測試出來if (!redisLimitExcutor.tryAccess(ip+url, 5, 1)) { throw new RuntimeException('調用頻繁');} 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')) {// 根據網卡取本機配置的IPInetAddress inet = null;try { inet = InetAddress.getLocalHost();} catch (UnknownHostException e) { return null;}ipAddress = inet.getHostAddress(); }}// 如果通過代理訪問,可能獲取2個IP,這時候去第二個(代理服務端IP)if (ipAddress.split(',').length > 1) { ipAddress = ipAddress.split(',')[1].trim();}return ipAddress; }}
測試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 寫業務邏輯return 'aaaaa'; }}4、運行項目,訪問接口
http://localhost:8080/demo/limit
當刷新頻率高了以后,就會報錯
5、碼云地址(GitHub經常訪問不到)
備注:
1、 redis的key可以根據實際情況設置,入例子中的ip+url,可以將全部流量進行控制,防止惡意刷接口,但需要注意的是,使用ip方式,要將QPS設置大一些,因為會出現整個大廈公用一個ip的情況。也可以使用url+userName,將QPS設置小一點,可以更加精準的限制api的訪問。2、可以將拋出異常進行全局捕獲和統一返回。
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