spring 29 异常解析器

ExceptionHandlerExceptionResolver

代码参考

点击查看代码

public static void main(String[] args) throws NoSuchMethodException {
        ExceptionHandlerExceptionResolver resolver = new ExceptionHandlerExceptionResolver();
        resolver.setMessageConverters(List.of(new MappingJackson2HttpMessageConverter()));
        resolver.afterPropertiesSet();

        MockHttpServletRequest request = new MockHttpServletRequest();
        MockHttpServletResponse response = new MockHttpServletResponse();
//        // 1.测试 json
//        HandlerMethod handlerMethod = new HandlerMethod(new Controller1(), Controller1.class.getmethod("foo"));
//        Exception e = new ArithmeticException("被零除");
//        resolver.resolveException(request, response, handlerMethod, e);
//        System.out.println(new String(response.getContentAsByteArray(), StandardCharsets.UTF_8));
//        // 2.测试 mav
//        HandlerMethod handlerMethod = new HandlerMethod(new Controller2(), Controller2.class.getmethod("foo"));
//        Exception e = new ArithmeticException("被零除");
//        ModelAndView mav = resolver.resolveException(request, response, handlerMethod, e);
//        System.out.println(mav.getModel());
//        System.out.println(mav.getViewName());
//        // 3.测试嵌套异常
//        HandlerMethod handlerMethod = new HandlerMethod(new Controller3(), Controller3.class.getmethod("foo"));
//        Exception e = new Exception("e1", new RuntimeException("e2", new IOException("e3")));
//        resolver.resolveException(request, response, handlerMethod, e);
//        System.out.println(new String(response.getContentAsByteArray(), StandardCharsets.UTF_8));

        // 4.测试异常处理方法参数解析
        HandlerMethod handlerMethod = new HandlerMethod(new Controller4(), Controller4.class.getmethod("foo"));
        Exception e = new Exception("e1");
        resolver.resolveException(request, response, handlerMethod, e);
        System.out.println(new String(response.getContentAsByteArray(), StandardCharsets.UTF_8));

static class Controller1 {
        public void foo() {

        }
        @ExceptionHandler
        @ResponseBody
        public Map<String, Object> handle(ArithmeticException e) {
            return Map.of("error", e.getMessage());
        }
    }

    static class Controller2 {
        public void foo() {

        }
        @ExceptionHandler
        public ModelAndView handle(ArithmeticException e) {
            return new ModelAndView("test2", Map.of("error", e.getMessage()));
        }
    }

    static class Controller3 {
        public void foo() {

        }
        @ExceptionHandler
        @ResponseBody
        public Map<String, Object> handle(IOException e3) {
            return Map.of("error", e3.getMessage());
        }
    }

    static class Controller4 {
        public void foo() {}
        @ExceptionHandler
        @ResponseBody
        public Map<String, Object> handler(Exception e, HttpServletRequest request) {
            System.out.println(request);
            return Map.of("error", e.getMessage());
        }
    }

小结

1. 它能够重用参数解析器、返回值处理器，实现组件重用
2. 它能够支持嵌套异常