SpringBoot利用Guava实现单机app限流访问

朴灿烈づ我的快乐病毒、 2024-03-17 13:32 14阅读 0赞

## SpringBoot利用Guava实现单机app限流访问 ##

物料准备：  
1.引入Guava依赖  
2.定义一个限流注解作用于api接口的方法上  
3.定义一个切面，对注解标注的方法实现一个限流访问

### 引入Guava依赖 ###

<dependency>
                <groupId>com.google.guava</groupId>
                <artifactId>guava</artifactId>
                <version>28.2-jre</version>
            </dependency>

### 定义注解@RateLimitAspect ###

package com.example.demo.service.guava;
    
    import java.lang.annotation.*;
    
    
    @Inherited
    @Documented
    @Target({
        ElementType.METHOD, ElementType.FIELD, ElementType.TYPE})
    @Retention(RetentionPolicy.RUNTIME)
    public @interface RateLimitAspect {
        
    }

### 定义对应的处理的AOP逻辑 ###

package com.example.demo.service.guava;
    
    import com.alibaba.fastjson.JSON;
    import com.example.demo.web.AjaxPubResponse;
    import com.google.common.util.concurrent.RateLimiter;
    import lombok.extern.slf4j.Slf4j;
    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.springframework.beans.factory.annotation.Autowired;
    import org.springframework.context.annotation.Scope;
    import org.springframework.stereotype.Component;
    
    import javax.servlet.ServletOutputStream;
    import javax.servlet.http.HttpServletResponse;
    import java.io.IOException;
    
    
    
    @Component
    @Scope
    @Aspect
    @Slf4j
    public class RateLimitAop {
        
    
        @Autowired
        private HttpServletResponse response;
        @Pointcut("@annotation(com.example.demo.service.guava.RateLimitAspect)")
        public void serviceLimit() {
        
        }
        private RateLimiter rateLimiter = RateLimiter.create(5.0); //比如说，我这里设置"并发数"为5
        @Around("serviceLimit()")
        public Object around(ProceedingJoinPoint joinPoint) {
        
            Boolean flag = rateLimiter.tryAcquire();
            Object obj = null;
            try {
        
                if (flag) {
        
                    obj = joinPoint.proceed();
                }else{
        
                    String result = JSON.toJSONString(AjaxPubResponse.error("2003", "未获取到许可"));
    //                String result = JSONObject.fromObject(AjaxPubResponse.error("100", "failure")).toString();
                    output(response, result);
                }
            } catch (Throwable e) {
        
                e.printStackTrace();
            }
            log.info("flag={},obj={}",flag,obj);
    //        System.out.println("flag=" + flag + ",obj=" + obj);
            return obj;
        }
    
    
        public void output(HttpServletResponse response, String msg) throws IOException {
        
            response.setContentType("application/json;charset=UTF-8");
            ServletOutputStream outputStream = null;
            try {
        
                outputStream = response.getOutputStream();
                outputStream.write(msg.getBytes("UTF-8"));
            } catch (IOException e) {
        
                e.printStackTrace();
            } finally {
        
                outputStream.flush();
                outputStream.close();
            }
        }
    
    }

--------------------

使用方法，把@RateLimitAspect 注解添加到需要限流的API接口上即可，如  
添加到@GetMapping 或 @PostMapping上