Sentinel自定义异常

Posted 2023-03-04 IT-熊猫

文章目录

• • 1.引言
  • 2.整体思路如下
  • 3.自定义异常类具体实现
  • 4.自定义前后返回对比

1.引言

通过sentinel做限流设置后，发现其返回的错误是："Blocked by Sentinel (flow limiting)"字符串，这严重不符合系统开发规范，因此萌生了对异常的改造念头。

2.整体思路如下

1.通过在搜索关键字“Blocked by Sentinel”发现存在于DefaultBlockExceptionHandler类中，而此类实现了BlockExceptionHandler接口，DefaultBlockExceptionHandler实现如下：

//
// Source code recreated from a .class file by IntelliJ IDEA
// (powered by Fernflower decompiler)
//

package com.alibaba.csp.sentinel.adapter.spring.webmvc.callback;

import com.alibaba.csp.sentinel.slots.block.BlockException;
import com.alibaba.csp.sentinel.util.StringUtil;
import java.io.PrintWriter;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

public class DefaultBlockExceptionHandler implements BlockExceptionHandler 
    public DefaultBlockExceptionHandler() 
    

    public void handle(HttpServletRequest request, HttpServletResponse response, BlockException e) throws Exception 
        response.setStatus(429);
        StringBuffer url = request.getRequestURL();
        if ("GET".equals(request.getMethod()) && StringUtil.isNotBlank(request.getQueryString())) 
            url.append("?").append(request.getQueryString());
        

        PrintWriter out = response.getWriter();
        out.print("Blocked by Sentinel (flow limiting)");
        out.flush();
        out.close();
    

2.自定义异常类MyBlockExceptionHandler，也实现BlockExceptionHandler接口

3.自定义异常类MyBlockExceptionHandler实现BlockExceptionHandler接口的handle方法， 并根据不同的异常规程返回不同的提示

4.让springboot启动的时候自定加载自定义异常类

3.自定义异常类具体实现

1. 定义MyBlockExceptionHandler

import com.alibaba.csp.sentinel.adapter.spring.webmvc.callback.BlockExceptionHandler;

import com.alibaba.csp.sentinel.slots.block.BlockException;
import com.alibaba.csp.sentinel.slots.block.authority.AuthorityException;
import com.alibaba.csp.sentinel.slots.block.degrade.DegradeException;
import com.alibaba.csp.sentinel.slots.block.flow.FlowException;
import com.alibaba.csp.sentinel.slots.block.flow.param.ParamFlowException;
import com.alibaba.csp.sentinel.slots.system.SystemBlockException;
import com.charlie.cloudconsumer.common.utils.AjaxResult;
import com.fasterxml.jackson.databind.ObjectMapper;
import lombok.extern.slf4j.Slf4j;
import org.springframework.context.annotation.Configuration;
import org.springframework.http.MediaType;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;


@Slf4j
@Configuration
public class MyBlockExceptionHandler implements BlockExceptionHandler 

    @Override

    public void handle(HttpServletRequest httpServletRequest,HttpServletResponse httpServletResponse,BlockException e)throws Exception 
        log.info("urlBlock.......................");
        AjaxResult ajaxResult =null;

        //不同的异常返回不同的提示语
        if(einstanceof FlowException) //限流异常
            ajaxResult =AjaxResult.builder().status(100).msg("您的访问过于频繁，请稍后重试").build();
        else if (einstanceof DegradeException) //降级异常
            ajaxResult =AjaxResult.builder().status(101).msg("调用服务响应异常,已进行降级").build();
        else if (einstanceof ParamFlowException) //热点参数异常
            ajaxResult =AjaxResult.builder().status(102).msg("您对热点参数访问过于频繁，请稍后重试").build();
        else if (einstanceof SystemBlockException) //系统保护规则
            ajaxResult =AjaxResult.builder().status(103).msg("已触碰系统的红线规则，请检查访问参数").build();
        else if (einstanceof AuthorityException) //授权规则
            ajaxResult =AjaxResult.builder().status(104).msg("授权规则检测不同，请检查访问参数").build();
        else //其他规则
            ajaxResult =AjaxResult.builder().status(105).msg("非法访问，请稍后重试").build();
        

        httpServletResponse.setStatus(500);
        httpServletResponse.setCharacterEncoding("utf-8");
        httpServletResponse.setContentType(MediaType.APPLICATION_JSON_VALUE);
        //springmvc的一个json转换类(jockson)
        new ObjectMapper().writeValue(httpServletResponse.getWriter(),ajaxResult);
    

4.自定义前后返回对比

1. sentinel dashbord 限流规则如图：
   

2. 改造前返回结果

3. 改造后返回结果