@ControllerAdvice实现优雅地处理异常

@ControllerAdvice，是Spring3.2提供的新注解,它是一个Controller增强器,可对controller中被 @RequestMapping注解的方法加一些逻辑处理。最常用的就是异常处理

统一异常处理

需要配合@ExceptionHandler使用。
当将异常抛到controller时,可以对异常进行统一处理,规定返回的json格式或是跳转到一个错误页面

//全局异常捕捉处理
@ControllerAdvice
public class CustomExceptionHandler {

    @ResponseBody
    @ExceptionHandler(value = Exception.class)
    public Map errorHandler(Exception ex) {
        Map map = new HashMap();
        map.put("code", 400);
        //判断异常的类型,返回不一样的返回值
        if(ex instanceof MissingServletRequestParameterException){
            map.put("msg","缺少必需参数："+((MissingServletRequestParameterException) ex).getParameterName());
        }
        else if(ex instanceof MyException){
            map.put("msg","这是自定义异常");
        }
        return map;
    }
}

//自定义异常类
@Data
public class MyException extends RuntimeException {
    private long code;
    private String msg;

    public MyException(Long code, String msg){
        super(msg);
        this.code = code;
        this.msg = msg;
    }

    public MyException(String msg){
        super(msg);
        this.msg = msg;
    }
}
@RestController
public class TestController {
    @RequestMapping("testException")
    public String testException() throws Exception{
        throw new MissingServletRequestParameterException("name","String");
    }

    @RequestMapping("testMyException")
    public String testMyException() throws MyException{
        throw new MyException("i am a myException");
    }
}

分别访问testException和testMyException接口,可得到以下结果

{"msg":"缺少必需参数：name","code":400}
{"msg":"这是自定义异常","code":400}

如果不需要返回json数据，而要渲染某个页面模板返回给浏览器，那么可以这么实现：

@ExceptionHandler(value = MyException.class)
public ModelAndView myErrorHandler(MyException ex) {
    ModelAndView modelAndView = new ModelAndView();
    //指定错误页面的模板页
    modelAndView.setViewName("error");
    modelAndView.addObject("code", ex.getCode());
    modelAndView.addObject("msg", ex.getMsg());
    return modelAndView;
}

这样子很方便吧~