java

spring boot 全局异常拦截并通过 webhook 发送到钉钉机器人

当后端程序由于各种原因出错时，如果将错误信息直接抛给客户端，用户肯定会一脸懵逼，除非当时的用户是你们的开发，本文主要讲述如果拦截全局异常，不把异常抛给用户，同时，如果做过客户端，应该知道，Android和ios都有第三方crash上报平台，如果能在出错后发消息到钉钉则很方便，本文主要解决这两件事。

spring boot 拦截全局异常

拦截异常主要使用 @ControllerAdvice 注解，具体来讲就是，新建一个包，比如 crash，然后新建一个类比如 GlobalDefaultExceptionHandler，这个类的代码如下：

import com.alibaba.fastjson.JSON;
import io.sentry.Sentry;
import org.springframework.web.bind.annotation.ControllerAdvice;
import org.springframework.web.bind.annotation.ExceptionHandler;
import org.springframework.web.bind.annotation.ResponseBody;
import top.kpromise.user.response.Result;

import javax.servlet.http.HttpServletRequest;
import java.io.IOException;
import java.nio.charset.StandardCharsets;
import java.text.SimpleDateFormat;
import java.util.ArrayList;
import java.util.Date;
import java.util.Map;

@ControllerAdvice
public class GlobalDefaultExceptionHandler {

    @ExceptionHandler(Exception.class)
    @ResponseBody
    public Map<String, Object> defaultExceptionHandler(HttpServletRequest request, Exception e) {
        e.printStackTrace();
        System.out.println("uri " + request.getRequestURI());
        String params = JSON.toJSONString(request.getParameterMap());
        if (params.equals("{}")) {
            params = getRequestJson(request);
        }
        String title = request.getRequestURI();
        SimpleDateFormat df = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
        String crashTime = df.format(new Date());
        String text = "#### API 请求失败 @13067856109\n" +
                "> url " + request.getRequestURI() + "\n\n" +
                "> 请求参数 \n" + params + "\n\n" +
                "> 堆栈信息 \n" + e.getMessage() + "\n\n" +
                "> ###### 出错时间 " + crashTime + " \n";
        ArrayList<String> phones = new ArrayList<>();
        phones.add("13067856109");
        new DingTalkMessage(new DingTalkMessageBuilder().markdownMessage(title, text).at(phones)).send();
        Sentry.capture(e);
        return Result.data(null, "系统异常，请联系客服");
    }

    private static String getRequestJsonString(HttpServletRequest request)
            throws Exception {
        String submitMethod = request.getMethod().toUpperCase();
        if (submitMethod.equals("GET")) {
            return new String(request.getQueryString().getBytes(StandardCharsets.ISO_8859_1), StandardCharsets.UTF_8)
                    .replaceAll("%22", "\"");
        } else {
            return getRequestPostStr(request);
        }
    }

    private static String getRequestJson(HttpServletRequest request) {
        try {
            return getRequestJsonString(request);
        } catch (Exception e) {
            return null;
        }
    }

    private static byte[] getRequestPostBytes(HttpServletRequest request)
            throws IOException {
        int contentLength = request.getContentLength();
        if (contentLength < 0) {
            return null;
        }
        byte[] buffer = new byte[contentLength];
        for (int i = 0; i < contentLength; ) {
            int readLen = request.getInputStream().read(buffer, i, contentLength - i);
            if (readLen == -1) {
                break;
            }
            i += readLen;
        }
        return buffer;
    }

    private static String getRequestPostStr(HttpServletRequest request)
            throws Exception {
        byte[] buffer = getRequestPostBytes(request);
        String charEncoding = request.getCharacterEncoding();
        if (charEncoding == null) {
            charEncoding = "UTF-8";
        }
        if (buffer == null) {
            return "{}";
        }
        return new String(buffer, charEncoding);
    }
}

这里，我获取了用户请求的 url，以及参数，然后调用了钉钉机器人，总结起来，要拦截全局异常，只需要：新增一个类，这个类添加 @ControllerAdvice 注解然后这个类里写一个处理异常的方法，这个方法添加 @ExceptionHandler(Exception.class) 和 @ResponseBody 注解，前者的意思是，这个方法可以处理所有的 Exception ，后者的意思是重写返回的数据（没错，这么理解更简单），这就够了。但是这里，我增加了获取用户上传的 json 字符串以及发送到钉钉机器人，而且还发送到了自建的sentry 上面。

钉钉机器人文档可参考：https://open-doc.dingtalk.com/microapp/serverapi2/qf2nxq

DingTalkMessage 源码如下：

import okhttp3.*;

import java.io.IOException;

public class DingTalkMessage {

    private static final String URL = "https://oapi.dingtalk.com/robot/send?access_token=" +
            "2ce54522b84e1c7193e9998e9b9a2afd859aa7e635354d55a91cc6xxxxxx";

    private DingTalkMessageBuilder builder;

    public DingTalkMessage(DingTalkMessageBuilder builder) {
        this.builder = builder;
    }

    public void send() {
        String json = builder.build();

        OkHttpClient okHttpClient = new OkHttpClient();
        RequestBody body = RequestBody.create(MediaType.parse("application/json; charset=utf-8"), json);
        Request request = new Request.Builder().post(body).url(URL).build();

        okHttpClient.newCall(request).enqueue(new Callback() {
            @Override
            public void onFailure(Call call, IOException e) {
                e.getMessage();
            }

            @Override
            public void onResponse(Call call, okhttp3.Response response) {
                try {
                    ResponseBody responseBody = response.body();
                    if (responseBody != null) {
                        System.out.println(responseBody.string());
                    }
                }catch (Exception ignore){

                }
            }
        });
    }
}

DingTalkMessageBuilder 源码如下：

import com.alibaba.fastjson.JSON;

import java.util.ArrayList;
import java.util.HashMap;
import java.util.Map;

public class DingTalkMessageBuilder {

    private final HashMap<String, Object> map;

    public DingTalkMessageBuilder() {
        map = new HashMap<>();
    }

    public DingTalkMessageBuilder markdownMessage(String title, String text) {
        map.put("msgtype", "markdown");
        Map<String, String> contentMap = new HashMap<>();
        contentMap.put("title", title);
        contentMap.put("text", text);
        map.put("markdown", contentMap);
        return this;
    }

    public DingTalkMessageBuilder at(ArrayList<String> phones) {
        Map<String, Object> at = new HashMap<>();
        at.put("atMobiles", phones);
        at.put("isAtAll", false);
        map.put("at", at);
        return this;
    }

    String build() {
        return JSON.toJSONString(map);
    }
}

具体代码请点击下面，如果觉得有用请给个 star 谢谢。