spring异常+自定义以及使用

1、首先自定义异常

DataException：

package com.wbg.maven1128.exception;

public class DataException extends Exception {
    public DataException(){

    }
    public DataException(String msg){
            super(msg);
    }
}

DbException：

package com.wbg.maven1128.exception;

public class DbException extends Exception {

    public DbException(){

    }
    public DbException(String msg){
        super(msg);
    }
}

2、在dao层把异常抛了

　在服务层做好

不使用注解方法

在控制层使用

@Controller
@RequestMapping("/order")
public class OrdersController {

    @Autowired
    private OrdersService ordersService;

    @PostMapping(produces = "application/json;charset=utf-8")
    @ResponseBody
    public String add(Orders orders ){
       System.out.println(orders);
        try {
            ordersService.insert(orders);
      }catch(DbException e){
            return e.getMessage();
        } catch (DataException e) {
            return e.getMessage();
        }
        return "成功";
    }
    @GetMapping
    public String index(){
        return "order_add";
    }

1、自定义AbstractHandlerExceptionResolver

　　自定义就是当遇到AbstractHandlerExceptionResolver异常的时候直接进入自定义的异常，不再进入AbstractHandlerExceptionResolver

　　第一步：创建一个类来进行继承AbstractHandlerExceptionResolver类

MyExceptionResolver ：

package com.wbg.maven1128.exception;

import org.springframework.beans.TypeMismatchException;
import org.springframework.web.servlet.ModelAndView;
import org.springframework.web.servlet.handler.AbstractHandlerExceptionResolver;

import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

public class MyExceptionResolver extends AbstractHandlerExceptionResolver {
    @Override
    protected ModelAndView doResolveException(HttpServletRequest request, HttpServletResponse response, Object handler, Exception ex) {
        if(ex instanceof DbException){
            return new ModelAndView("数据库错误");
        }else if(ex instanceof TypeMismatchException){
            return new ModelAndView("TypeMismatchException");
        }
        return null;
    }
}

　　第二步：进行在xml注册

<bean class="com.wbg.maven1128.exception.MyExceptionResolver"/>

　　

　　最后直接在方法体上抛出异常即可throws Exception

2、使用ExceptionHandler注解方式

@Controller
@RequestMapping("/order")
public class OrdersController {
    @Autowired
    private OrdersService ordersService;

    @PostMapping(produces = "application/json;charset=utf-8")
    @ResponseBody
    public String add(Orders orders ) throws Exception {
            ordersService.insert(orders);
        return "成功";
    }
    @GetMapping
    public String index(){
        return "order_add";
    }

    @ExceptionHandler(DbException.class)
    public String handlerDbException(Exception ex, Model model){
        model.addAttribute("err",ex.getMessage());
        return "err1";
    }
    @ExceptionHandler(DataException.class)
    public ModelAndView handlerDbException2(Exception ex, Model model){
        model.addAttribute("err",ex.getMessage());
        return new ModelAndView("err2");
    }

3、使用@ControllerAdvice注解（推荐）

1、首先创建一个类，在这个类上加注解

2、在该类中写方法，方法上使用@ExceptionHandler注解进行捕获异常

3、然后在Controller层直接抛出异常、会自动捕获

package com.wbg.maven1128.controller;

import com.wbg.maven1128.exception.DbException;
import org.springframework.http.HttpStatus;
import org.springframework.stereotype.Component;
import org.springframework.web.bind.annotation.ControllerAdvice;
import org.springframework.web.bind.annotation.ExceptionHandler;
import org.springframework.web.bind.annotation.ResponseBody;
import org.springframework.web.bind.annotation.ResponseStatus;

@Component
@ControllerAdvice
public class AllControllerAdvice {
    // 这个处理，对所有的 Controller 都会有效
    @ExceptionHandler(Exception.class)
    @ResponseStatus(value = HttpStatus.URI_TOO_LONG)
    @ResponseBody
    public String handlerDbException3 () {
        return "ksjfksd";
    }
    @ExceptionHandler(DbException.class)
    @ResponseStatus(value = HttpStatus.URI_TOO_LONG)
    @ResponseBody
    public String DbException3 () {
        return "ksjfksd";
    }
    @ExceptionHandler(RuntimeException.class)
    public String handlerDbException4 () {
        return "runtime";
    }
}

测试：