Java 实现分布式服务的调用链跟踪

public class Request<T> implements Serializable {
    //header：携带需要传递的信息
    private RequestHeader header;
    //业务参数
    private T bizModel;
    //...省略get set
}
public class RequestHeader implements Serializable {

    //调用链唯一ID
    private String traceId;
    //当前用户Id
    private String userId;
    //上游调用方appId
    private String callAppId;
    //...省略get set
}

    @ApiMethod
    @PostMapping("/test")
    @ApiOperation(value = "test", notes = "", response = String.class)
    public Response<ExampleRespDTO> test(@RequestBody Request<ExampleReqDTO> req) {
        ExampleRespDTO exampleRespDTO = new ExampleRespDTO();
        exampleRespDTO.setName(req.getBizModel().getName());

        //输出当前应用的header信息
         System.out.println("上游的traceId："+RequestContext.getHeader().getTraceId());
        System.out.println("上游的callAppId："+RequestContext.getHeader().getCallAppId());
        System.out.println("上游的userId："+RequestContext.getHeader().getUserId());


        /***
         * 模拟调用其他应用服务
         * 通过RPCRequest 来构建request对象
         */
        Request<OtherAppServiceReqDTO>  otherAppServiceReqDTORequest =RPCRequest.createRequest(new OtherAppServiceReqDTO());

        //输出下游应用的header信息
        System.out.println("调用下游的traceId："+otherAppServiceReqDTORequest.getHeader().getTraceId());
        System.out.println("调用下游的callAppId："+otherAppServiceReqDTORequest.getHeader().getCallAppId());
        System.out.println("调用下游的userId："+otherAppServiceReqDTORequest.getHeader().getUserId());

        return Response.successResponse(exampleRespDTO);
    }

public class RPCRequest {
    public static <T> Request<T> createRequest(T requestData){
        Request<T> request = new Request();
        RequestHeader requestHeader=new RequestHeader();
        requestHeader.setTraceId(RequestContext.getHeader().getTraceId());
        requestHeader.setUserId(RequestContext.getHeader().getUserId());
        requestHeader.setCallAppId(AppConfig.CURRENT_APP_ID);
        request.setHeader(requestHeader);
        request.setBizModel(requestData);
        return request;
    }
}

public class RequestContext {
  private static ThreadLocal<RequestHeader> threadLocal=new ThreadLocal<>();
   public static void setHeader(RequestHeader header){
       threadLocal.set(header);
   }
   public static RequestHeader getHeader(){
       return threadLocal.get();
   }
   public static void clear(){
       threadLocal.remove();
   }
}

public class ApiHandler {
    public ApiHandler() {
    }

    public Response handleApiMethod(ProceedingJoinPoint pjp, ApiMethod apiMethod) {
        //获取上游调用方的request header
        Object[] args = pjp.getArgs();
        Request request = (Request) args[0];
        RequestHeader header = request.getHeader();
        //将header加入到当前request 到ThreadLocal保存
        RequestContext.setHeader(header);
        Response response = null;
        try {
            //构建response header
            ResponseHeader responseHeader = new ResponseHeader();
            responseHeader.setTraceId(RequestContext.getHeader().getTraceId());
            //执行service方法
            response = (Response) pjp.proceed(args);
            response.setHeader(responseHeader);

        } catch (Throwable throwable) {
            throwable.printStackTrace();
        }finally {
            //清除ThreadLocal中当前请求的header 对象
            RequestContext.clear();
        }
        return response;

    }
}