Limit

package me.zhengjie.common.aop.limit;

import java.lang.annotation.ElementType;
import java.lang.annotation.Retention;
import java.lang.annotation.RetentionPolicy;
import java.lang.annotation.Target;

/**
 * @author jacky
 */
@Target(ElementType.METHOD)
@Retention(RetentionPolicy.RUNTIME)
public @interface Limit {

    // 资源名称，用于描述接口功能
    String name() default "";

    // 资源 key
    String key() default "";

    // key prefix
    String prefix() default "";

    // 时间的，单位秒
    int period();

    // 限制访问次数
    int count();

    // 限制类型
    LimitType limitType() default LimitType.CUSTOMER;

}

package me.zhengjie.common.aop.limit;

public enum LimitType {
    CUSTOMER,
//     by ip addr
    IP;
}

package me.zhengjie.common.aop.limit;

import com.google.common.collect.ImmutableList;
import me.zhengjie.common.exception.BadRequestException;
import me.zhengjie.common.utils.IpUtil;
import me.zhengjie.common.utils.RequestHolder;
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.annotation.Pointcut;
import org.aspectj.lang.reflect.MethodSignature;
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.data.redis.core.script.DefaultRedisScript;
import org.springframework.data.redis.core.script.RedisScript;
import org.springframework.stereotype.Component;


import javax.servlet.http.HttpServletRequest;
import java.lang.reflect.Method;

@Aspect
@Component
public class LimitAspect {
    @Autowired
    private RedisTemplate redisTemplate;
    private static final Logger logger = LoggerFactory.getLogger(LimitAspect.class);


    @Pointcut("@annotation(Limit)")
    public void pointcut() {
//
    }

    @Around("pointcut()")
    public Object around(ProceedingJoinPoint joinPoint) throws Throwable {
        HttpServletRequest request = RequestHolder.getHttpServletRequest();
        MethodSignature signature = (MethodSignature) joinPoint.getSignature();
        Method signatureMethod = signature.getMethod();
        Limit limit = signatureMethod.getAnnotation(Limit.class);
        LimitType limitType = limit.limitType();
        String name = limit.name();
        String key = limit.key();
        if (StringUtils.isEmpty(key)) {
            switch (limitType) {
                case IP:
                    key = IpUtil.getIP(request);
                    break;
                default:
                    key = signatureMethod.getName();
            }
        }

        ImmutableList keys = ImmutableList.of(StringUtils.join(limit.prefix(), "_", key, "_", request.getRequestURI().replaceAll("/","_")));

        String luaScript = buildLuaScript();
        RedisScript<Number> redisScript = new DefaultRedisScript<>(luaScript, Number.class);
        Number count = (Number) redisTemplate.execute(redisScript, keys, limit.count(), limit.period());
        if (null != count && count.intValue() <= limit.count()) {
            logger.info("第{}次访问key为 {}，描述为 [{}] 的接口", count, keys, limit.name());
            return joinPoint.proceed();
        } else {
            throw new BadRequestException("访问次数受限制");
        }
    }

    /**
     * 限流脚本
     */
    private String buildLuaScript() {
        return "local c" +
                "\nc = redis.call(‘get‘,KEYS[1])" +
                "\nif c and tonumber(c) > tonumber(ARGV[1]) then" +
                "\nreturn c;" +
                "\nend" +
                "\nc = redis.call(‘incr‘,KEYS[1])" +
                "\nif tonumber(c) == 1 then" +
                "\nredis.call(‘expire‘,KEYS[1],ARGV[2])" +
                "\nend" +
                "\nreturn c;";
    }
}

package me.zhengjie.monitor.rest;

import me.zhengjie.common.aop.limit.Limit;
import org.springframework.security.access.prepost.PreAuthorize;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;

import java.util.concurrent.atomic.AtomicInteger;

@RestController
@RequestMapping("test")
public class TestController {
    private static final AtomicInteger ATOMIC_INTEGER = new AtomicInteger();

    /**
     * 测试限流注解，下面配置说明该接口 60秒内最多只能访问 10次，保存到redis的键名为 limit_test，
     */
    @Limit(key = "test", period = 60, count = 10, name = "testLimit", prefix = "limit")
    @GetMapping("limit")
    public int testLimit() {
        return ATOMIC_INTEGER.incrementAndGet();
    }
}