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如何在春季开机时处理延迟结果中的异常?

nonblocking spring-boot spring java

Almas Abdrazak · 技术社区 · 7 年前

我有一个休息方法:

@RequestMapping(value = "wash/washHistory", method = RequestMethod.GET, produces = "application/json;charset=UTF-8")
    @ResponseBody
    public DeferredResult<String> getWashHistory(@RequestParam(value = "sid", required = true, defaultValue = "") String sid,
            HttpServletResponse response, HttpServletRequest request,
            @RequestParam(value = "sort", defaultValue = "") String sortType,
            @RequestParam(value = "order", defaultValue = "") String order,
            @RequestParam(value = "limit", defaultValue = "") String limit,
            @RequestParam(value = "offset", defaultValue = "") String offset) {

        System.out.println("Thread: "+Thread.currentThread());
        final Integer managerId = checkSession(sid);      
        DeferredResult<String> defResult = new DeferredResult<>();
        new Thread(() -> {
                final String result = washController.getWashHistory( managerId, order, sortType, limit, offset);
                defResult.setResult(result);            
        }).start();
    return defResult;
    }

在“getWashHistory”中,我抛出以下自定义异常:

throw new InvalidUserInputException("Wrong offset", this.getClass().getSimpleName(), "getWashHist", params);

为了处理这个异常,我使用了以下类:

@ControllerAdvice
@EnableWebMvc
public class GlobalExceptionHandler {
 @ExceptionHandler(value = InvalidUserInputException.class)
    public ResponseEntity<String> invalidUserInputExc(InvalidUserInputException e) {
          logger.log("GMoika", e.error().getClassName(), e.error().getMethodName(), e.error().getParams(), e.error().getCause());
        return ResponseEntity.
                status(HttpStatus.BAD_REQUEST).
                body(e.error().getErrorCode());  
    }
}

我找到了一种解决方法:

defResult.onTimeout(new Runnable() {
        @Override
        public void run() {
            defResult.setErrorResult("Explanation goes here.");
            response.setStatus(HttpServletResponse.SC_PARTIAL_CONTENT); //or SC_NO_CONTENT
        }
    });

在我的GlobalExceptionHandler类中,有没有其他可能的方法来处理DeferredResult中的异常?

3 回复 | 直到 6 年前

jny harshit 7 年前

DeferredResult has方法 setErrorResult documentation :

处理时就像处理程序引发异常一样。

Sri9911 Almas Abdrazak 6 年前

@jny的决定在大多数情况下是正确的,但对我来说,我找到了另一种方法在我的rest控制器中,我添加了以下代码:

new Thread(() -> {          
            Thread.currentThread().setUncaughtExceptionHandler(new SeparateThreadsExceptionHandler(defResult));
            final String result = washController.getWashHistory(managerId, order, sortType, limit, offset);
            defResult.setResult(result);
        }).start();

和一个SeparateThreadsExceptionHandler类:

public class SeparateThreadsExceptionHandler implements Thread.UncaughtExceptionHandler{
    private DeferredResult<String> dr;
    public SeparateThreadsExceptionHandler(DeferredResult<String> dr){
        this.dr = dr;
    }
    @Override
    public void uncaughtException(Thread t, Throwable e) {
        if(e instanceof InvalidUserInputException){
           InvalidUserInputException throwableException =  (InvalidUserInputException)e;
            dr.setResult(throwableException.error().getErrorCode());
        } else {
            dr.setResult(UnknownException.UNKNOWN_ERROR_CODE);
        }
    }

}

当抛出自定义异常时,我可以将一些字符串错误消息设置为DeferredResult。在我的示例中,它是前端的错误代码。

Kacper86 6 年前

我用过 setErrorResult

以下是我的控制器方法的主体:

DeferredResult<Wrapper<Object>> deferredResult = new DeferredResult<>();

ForkJoinPool.commonPool().submit(() -> {
    try {
        Wrapper<Object> response = ...
        deferredResult.setResult(response);
    } catch (Exception e) {
        deferredResult.setErrorResult(e);
    }
});

return deferredResult;

在这种情况下,在新线程中抛出的异常被传递给全局@ExceptionHandler