前言
該篇介紹的内容如題,就是利用redis實作接口的限流( 某時間範圍内 最大的通路次數 ) 。
正文
慣例,先看下我們的實戰目錄結構:
首先是pom.xml 核心依賴:
<!--用于redis資料庫連接配接-->
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-data-redis</artifactId>
</dependency>
<!--用于redis lettuce 連接配接池pool使用-->
<dependency>
<groupId>org.apache.commons</groupId>
<artifactId>commons-pool2</artifactId>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-web</artifactId>
</dependency>
然後是application.yml裡面的redis接入配置:
spring:
redis:
lettuce:
pool:
#連接配接池最大連接配接數 使用負值代表無限制 預設為8
max-active: 10
#最大空閑連接配接 預設8
max-idle: 10
#最小空閑連接配接 預設0
min-idle: 1
host: 127.0.0.1
password: 123456
port: 6379
database: 0
timeout: 2000ms
server:
port: 8710
redis的配置類, RedisConfig.java:
ps:可以看到日期是18年的,因為這些redis的整合教程,在這個系列裡面一共有快10篇,不了解的看客如果感興趣可以去看一看。
import com.fasterxml.jackson.annotation.JsonAutoDetect;
import com.fasterxml.jackson.annotation.PropertyAccessor;
import com.fasterxml.jackson.databind.ObjectMapper;
import org.springframework.cache.CacheManager;
import org.springframework.cache.annotation.EnableCaching;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.data.redis.cache.RedisCacheConfiguration;
import org.springframework.data.redis.cache.RedisCacheManager;
import org.springframework.data.redis.connection.RedisConnectionFactory;
import org.springframework.data.redis.core.RedisTemplate;
import org.springframework.data.redis.core.StringRedisTemplate;
import org.springframework.data.redis.serializer.Jackson2JsonRedisSerializer;
import org.springframework.data.redis.serializer.RedisSerializationContext;
import org.springframework.data.redis.serializer.StringRedisSerializer;
import static org.springframework.data.redis.cache.RedisCacheConfiguration.defaultCacheConfig;
/**
* @Author: JCccc
* @CreateTime: 2018-09-11
* @Description:
*/
@Configuration
@EnableCaching
public class RedisConfig {
@Bean
public CacheManager cacheManager(RedisConnectionFactory connectionFactory) {
RedisCacheConfiguration cacheConfiguration =
defaultCacheConfig()
.disableCachingNullValues()
.serializeValuesWith(RedisSerializationContext.SerializationPair.fromSerializer(new Jackson2JsonRedisSerializer(Object.class)));
return RedisCacheManager.builder(connectionFactory).cacheDefaults(cacheConfiguration).build();
}
@Bean
public RedisTemplate<String, Object> redisTemplate(RedisConnectionFactory factory) {
RedisTemplate<String, Object> redisTemplate = new RedisTemplate<>();
redisTemplate.setConnectionFactory(factory);
Jackson2JsonRedisSerializer jackson2JsonRedisSerializer = new Jackson2JsonRedisSerializer(Object.class);
ObjectMapper om = new ObjectMapper();
om.setVisibility(PropertyAccessor.ALL, JsonAutoDetect.Visibility.ANY);
om.enableDefaultTyping(ObjectMapper.DefaultTyping.NON_FINAL);
jackson2JsonRedisSerializer.setObjectMapper(om);
//序列化設定 ,這樣為了存儲操作對象時正常顯示的資料,也能正常存儲和擷取
redisTemplate.setKeySerializer(new StringRedisSerializer());
redisTemplate.setValueSerializer(jackson2JsonRedisSerializer);
redisTemplate.setHashKeySerializer(new StringRedisSerializer());
redisTemplate.setHashValueSerializer(jackson2JsonRedisSerializer);
return redisTemplate;
}
@Bean
public StringRedisTemplate stringRedisTemplate(RedisConnectionFactory factory) {
StringRedisTemplate stringRedisTemplate = new StringRedisTemplate();
stringRedisTemplate.setConnectionFactory(factory);
return stringRedisTemplate;
}
}
自定義注解:
import java.lang.annotation.*;
/**
* @Author JCccc
* @Description
* @Date 2021/7/23 11:46
*/
@Inherited
@Documented
@Target({ElementType.FIELD, ElementType.TYPE, ElementType.METHOD})
@Retention(RetentionPolicy.RUNTIME)
public @interface RequestLimit {
/**
* 時間内 秒為機關
*/
int second() default 10;
/**
* 允許通路次數
*/
int maxCount() default 5;
//預設效果 : 10秒内 對于使用該注解的接口,隻能總請求通路數 不能大于 5次
}
接下來是攔截器 RequestLimitInterceptor.java:
攔截接口的方式 是通過 ip位址+接口url ,做時間内的通路計數
import com.elegant.testdemo.annotation.RequestLimit;
import com.elegant.testdemo.utils.IpUtil;
import com.fasterxml.jackson.databind.ObjectMapper;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.data.redis.core.RedisTemplate;
import org.springframework.stereotype.Component;
import org.springframework.web.method.HandlerMethod;
import org.springframework.web.servlet.HandlerInterceptor;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;
import java.util.concurrent.TimeUnit;
/**
* @Author JCccc
* @Description
* @Date 2021/7/23 11:49
*/
@Component
public class RequestLimitInterceptor implements HandlerInterceptor {
private final Logger log = LoggerFactory.getLogger(this.getClass());
@Autowired
private RedisTemplate<String, Object> redisTemplate;
@Override
public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler) throws Exception {
try {
if (handler instanceof HandlerMethod) {
HandlerMethod handlerMethod = (HandlerMethod) handler;
// 擷取RequestLimit注解
RequestLimit requestLimit = handlerMethod.getMethodAnnotation(RequestLimit.class);
if (null==requestLimit) {
return true;
}
//限制的時間範圍
int seconds = requestLimit.second();
//時間内的 最大次數
int maxCount = requestLimit.maxCount();
String ipAddr = IpUtil.getIpAddr(request);
// 存儲key
String key = ipAddr+":"+request.getContextPath() + ":" + request.getServletPath();
// 已經通路的次數
Integer count = (Integer) redisTemplate.opsForValue().get(key);
log.info("檢測到目前ip對接口={}已經通路的次數", request.getServletPath() , count);
if (null == count || -1 == count) {
redisTemplate.opsForValue().set(key, 1, seconds, TimeUnit.SECONDS);
return true;
}
if (count < maxCount) {
redisTemplate.opsForValue().increment(key);
return true;
}
log.warn("請求過于頻繁請稍後再試");
returnData(response);
return false;
}
return true;
} catch (Exception e) {
log.warn("請求過于頻繁請稍後再試");
e.printStackTrace();
}
return true;
}
public void returnData(HttpServletResponse response) throws IOException {
response.setCharacterEncoding("UTF-8");
response.setContentType("application/json; charset=utf-8");
ObjectMapper objectMapper = new ObjectMapper();
//這裡傳提示語可以改成自己項目的傳回資料封裝的類
response.getWriter().println(objectMapper.writeValueAsString("請求過于頻繁請稍後再試"));
return;
}
}
接下來是 攔截器的配置 WebConfig.java:
import com.elegant.testdemo.interceptor.RequestLimitInterceptor;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.context.annotation.Configuration;
import org.springframework.web.servlet.config.annotation.InterceptorRegistry;
import org.springframework.web.servlet.config.annotation.WebMvcConfigurer;
/**
* @Author JCccc
* @Description
* @Date 2021/7/23 11:52
*/
@Configuration
public class WebConfig implements WebMvcConfigurer {
@Autowired
private RequestLimitInterceptor requestLimitInterceptor;
@Override
public void addInterceptors(InterceptorRegistry registry) {
registry.addInterceptor(requestLimitInterceptor)
//攔截所有請求路徑
.addPathPatterns("/**")
//再設定 放開哪些路徑
.excludePathPatterns("/static/**","/auth/login");
}
}
最後還有兩個工具類
IpUtil
RedisUtil
最後寫個測試接口
TestController.java
import com.elegant.testdemo.annotation.RequestLimit;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RestController;
/**
* @Author JCccc
* @Description
* @Date 2021/7/23 11:55
*/
@RestController
public class TestController {
@GetMapping("/test")
@RequestLimit(maxCount = 3,second = 60)
public String test() {
return "你好,如果對你有幫助,請點贊加關注。";
}
}
這個/test接口的注解,我們設定的是 60秒内 最大通路次數為 3次 (實際應用應該是根據具體接口做相關的次數限制。)
然後使用postman測試一下接口:
前面三次都是請求通過的: