需求
公司里使用onebyone的方式删除数据，为了防止一段时间内删除数据过多，让我这边做一个接口限流，超过一定阈值后报异常，终止删除操作。
实现方式
创建自定义注解
@limit让使用者在需要的地方配置count(一定时间内最多访问次数)、period(给定的时间范围)，也就是访问频率。然后通过limitinterceptor拦截方法的请求， 通过 redis+lua 脚本的方式，控制访问频率。
源码
Limit 注解
用于配置方法的访问频率count、period
import javax.validation.constraints.Min;
import java.lang.annotation.*;
@Target({ElementType.METHOD, ElementType.TYPE})
@Retention(RetentionPolicy.RUNTIME)
@Inherited
@Documented
public @interface Limit {
/**
* key
*/
String key() default "";
/**
* Key的前缀
*/
String prefix() default "";
/**
* 一定时间内最多访问次数
*/
@Min(1)
int count();
/**
* 给定的时间范围 单位(秒)
*/
@Min(1)
int period();
/**
* 限流的类型(用户自定义key或者请求ip)
*/
LimitType limitType() default LimitType.CUSTOMER;
}LimitKey
用于标记参数，作为redis key值的一部分
import java.lang.annotation.ElementType;
import java.lang.annotation.Retention;
import java.lang.annotation.RetentionPolicy;
import java.lang.annotation.Target;
@Target(ElementType.PARAMETER)
@Retention(RetentionPolicy.RUNTIME)
public @interface LimitKey {
}LimitType
枚举，redis key值的类型，支持自定义key和ip、methodName中获取key
public enum LimitType {
/**
* 自定义key
*/
CUSTOMER,
/**
* 请求者IP
*/
IP,
/**
* 方法名称
*/
METHOD_NAME;
}RedisLimiterHelper
初始化一个限流用到的redisTemplate Bean
import org.springframework.beans.factory.annotation.Qualifier;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.data.redis.core.RedisTemplate;
import org.springframework.data.redis.core.StringRedisTemplate;
import org.springframework.data.redis.serializer.GenericJackson2JsonRedisSerializer;
import org.springframework.data.redis.serializer.StringRedisSerializer;
import java.io.Serializable;
@Configuration
public class RedisLimiterHelper {
@Bean
public RedisTemplate<String, Serializable> limitRedisTemplate(@Qualifier("defaultStringRedisTemplate") StringRedisTemplate redisTemplate) {
RedisTemplate<String, Serializable> template = new RedisTemplate<String, Serializable>();
template.setKeySerializer(new StringRedisSerializer());
template.setValueSerializer(new GenericJackson2JsonRedisSerializer());
template.setConnectionFactory(redisTemplate.getConnectionFactory());
return template;
}
}LimitInterceptor
使用 aop 的方式来拦截请求，控制访问频率
import com.google.common.collect.ImmutableList;
import com.yxt.qida.api.bean.service.xxv2.openapi.anno.Limit;
import com.yxt.qida.api.bean.service.xxv2.openapi.anno.LimitKey;
import com.yxt.qida.api.bean.service.xxv2.openapi.anno.LimitType;
import lombok.extern.slf4j.Slf4j;
import org.apache.commons.lang3.ArrayUtils;
import org.apache.commons.lang3.StringUtils;
import org.aspectj.lang.ProceedingJoinPoint;
import org.aspectj.lang.annotation.Around;
import org.aspectj.lang.annotation.Aspect;
import org.aspectj.lang.reflect.MethodSignature;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.context.annotation.Configuration;
import org.springframework.data.redis.core.RedisTemplate;
import org.springframework.data.redis.core.script.DefaultRedisScript;
import org.springframework.data.redis.core.script.RedisScript;
import org.springframework.web.context.request.RequestContextHolder;
import org.springframework.web.context.request.ServletRequestAttributes;
import javax.servlet.http.HttpServletRequest;
import java.io.Serializable;
import java.lang.annotation.Annotation;
import java.lang.reflect.Method;
@Slf4j
@Aspect
@Configuration
public class LimitInterceptor {
private static final String UNKNOWN = "unknown";
private final RedisTemplate<String, Serializable> limitRedisTemplate;
@Autowired
public LimitInterceptor(RedisTemplate<String, Serializable> limitRedisTemplate) {
this.limitRedisTemplate = limitRedisTemplate;
}
@Around("execution(public * *(..)) && @annotation(com.yxt.qida.api.bean.service.xxv2.openapi.anno.Limit)")
public Object interceptor(ProceedingJoinPoint pjp) {
MethodSignature signature = (MethodSignature) pjp.getSignature();
Method method = signature.getMethod();
Limit limitAnnotation = method.getAnnotation(Limit.class);
LimitType limitType = limitAnnotation.limitType();
int limitPeriod = limitAnnotation.period();
int limitCount = limitAnnotation.count();
/**
* 根据限流类型获取不同的key ,如果不传我们会以方法名作为key
*/
String key;
switch (limitType) {
case IP:
key = getIpAddress();
break;
case CUSTOMER:
key = limitAnnotation.key();
break;
case METHOD_NAME:
String methodName = method.getName();
key = StringUtils.upperCase(methodName);
break;
default:
throw new RuntimeException("limitInterceptor - 无效的枚举值");
}
/**
* 获取注解标注的 key，这个是优先级最高的，会覆盖前面的 key 值
*/
Object[] args = pjp.getArgs();
Annotation[][] paramAnnoAry = method.getParameterAnnotations();
for (Annotation[] item : paramAnnoAry) {
int paramIndex = ArrayUtils.indexOf(paramAnnoAry, item);
for (Annotation anno : item) {
if (anno instanceof LimitKey) {
Object arg = args[paramIndex];
if (arg instanceof String && StringUtils.isNotBlank((String) arg)) {
key = (String) arg;
break;
}
}
}
}
if (StringUtils.isBlank(key)) {
throw new RuntimeException("limitInterceptor - key值不能为空");
}
String prefix = limitAnnotation.prefix();
String[] keyAry = StringUtils.isBlank(prefix) ? new String[]{"limit", key} : new String[]{"limit", prefix, key};
ImmutableList<String> keys = ImmutableList.of(StringUtils.join(keyAry, "-"));
try {
String luaScript = buildLuaScript();
RedisScript<Number> redisScript = new DefaultRedisScript<Number>(luaScript, Number.class);
Number count = limitRedisTemplate.execute(redisScript, keys, limitCount, limitPeriod);
if (count != null && count.intValue() <= limitCount) {
return pjp.proceed();
} else {
String classPath = method.getDeclaringClass().getName() + "." + method.getName();
throw new RuntimeException("limitInterceptor - 限流被触发："
+ "class:" + classPath
+ ", keys:" + keys
+ ", limitcount:" + limitCount
+ ", limitPeriod:" + limitPeriod + "s");
}
} catch (Throwable e) {
if (e instanceof RuntimeException) {
throw new RuntimeException(e.getLocalizedMessage());
}
throw new RuntimeException("limitInterceptor - 限流服务异常");
}
}
/**
* lua 脚本，为了保证执行 redis 命令的原子性
*/
public String buildLuaScript() {
StringBuilder lua = new StringBuilder();
lua.append("local c");
lua.append("\nc = redis.call('get',KEYS[1])");
// 调用不超过最大值，则直接返回
lua.append("\nif c and tonumber(c) > tonumber(ARGV[1]) then");
lua.append("\nreturn c;");
lua.append("\nend");
// 执行计算器自加
lua.append("\nc = redis.call('incr',KEYS[1])");
lua.append("\nif tonumber(c) == 1 then");
// 从第一次调用开始限流，设置对应键值的过期
lua.append("\nredis.call('expire',KEYS[1],ARGV[2])");
lua.append("\nend");
lua.append("\nreturn c;");
return lua.toString();
}
public String getIpAddress() {
HttpServletRequest request = ((ServletRequestAttributes) RequestContextHolder.getRequestAttributes()).getRequest();
String ip = request.getHeader("x-forwarded-for");
if (ip == null || ip.length() == 0 || UNKNOWN.equalsIgnoreCase(ip)) {
ip = request.getHeader("Proxy-Client-IP");
}
if (ip == null || ip.length() == 0 || UNKNOWN.equalsIgnoreCase(ip)) {
ip = request.getHeader("WL-Proxy-Client-IP");
}
if (ip == null || ip.length() == 0 || UNKNOWN.equalsIgnoreCase(ip)) {
ip = request.getRemoteAddr();
}
return ip;
}
}TestService
使用方式示例
@Limit(period = 10, count = 10)
public String delUserByUrlTest(@LimitKey String token, String thirdId, String url) throws IOException {
return "success";
} 
