@ExceptionHandler处理异常,在controller层写以下方法，返回前端的结果为{"msg":"Exception"},如果模板引擎是thymeleaf则可以return一个String字符串跳转到templates页面

或者另外新建一个处理器类添加@ControllerAdvice注解，并写以下方法

@ExceptionHandler(value = {Exception.class})

@ResponseBody

public Map ExceptionHandler(Exception e){

    Map map = new HashMap();

    map.put("msg","Exception");

    return map;

}

在@Configuration修饰的Java配置类中添加以下代码

@Bean

public SimpleMappingExceptionResolver getSimpleMappingExceptionResolver(){

    SimpleMappingExceptionResolver simpleMappingExceptionResolver = new SimpleMappingExceptionResolver();

    Properties properties = new Properties();

    properties.setProperty("java.lang.Exception","index");  //表示发生Exception异常时跳转到templates下的index页面

    simpleMappingExceptionResolver.setExceptionMappings(properties);

    return simpleMappingExceptionResolver;

}

实现HandlerExceptionResolver接口

@Component

public class MyHandlerExceptionResolver implements HandlerExceptionResolver {

    @Override

    public ModelAndView resolveException(HttpServletRequest httpServletRequest, HttpServletResponse httpServletResponse, Object o, Exception e)  {

        System.out.println("全局的自定义异常处理被触发...");

        ModelAndView modelAndView = new ModelAndView();    //要返回ModelAndView对象，不能返回null

        Map map = new HashMap();

        if(e instanceof NullPointerException){            //如果发生空指针异常的处理

            map.put("Exception", e.toString());

            map.put("msg","find exception");

            JSON parse = JSONUtil.parseObj(map, false);

            try {

                httpServletResponse.getWriter().write(parse.toString());    //map序列化成json返回给浏览器

            } catch (IOException ex) {

                ex.printStackTrace();

            }

        }

        return modelAndView;

    }

}