java - Spring MVC 中的嵌套异常处理

Question

我收到以下错误:

org.springframework.web.util.NestedServletException: Request processing failed; nested exception is java.lang.NullPointerException

为了在 Controller 中处理这个问题，我使用了以下代码:

@ExceptionHandler(NestedServletException.class)
public ModelAndView handleServletErrors(){
    System.out.println("Servlet Exception is thrown");
    ModelAndView mv = new ModelAndView("error"); 
    mv.addObject("error", "Error encountered while processing reqeust.");
    return mv;
}

但这并没有处理上面抛出的异常。而如果我使用 NullPointerException 类而不是 NestedServletException，它就可以工作。由于 Spring 正在抛出异常以响应 NullPointerException 是否应该由上面的代码处理？

Answer 1

引用@ExceptionHandler的文档:

Annotation for handling exceptions in specific handler classes and/or handler methods.

此注释将允许方法处理由处理程序方法抛出的异常，即用 @RequestMapping 注释的方法。引用 Spring reference :

You can do that with @ExceptionHandler methods. When declared within a controller such methods apply to exceptions raised by @RequestMapping methods of that contoroller (or any of its sub-classes). You can also declare an @ExceptionHandler method within an @ControllerAdvice class in which case it handles exceptions from @RequestMapping methods from many controllers.

由于您的处理程序抛出的异常是 NullPointerException，异常处理程序方法将处理该特定异常。它不会处理 Spring 用于封装 servlet 异常的通用 NestedServletException。