SpringBoot异常处理

2020-10-17

1. 定义错误码

ResponseCode.java用来记录错误码

public enum ResponseCode {

    NOT_FOUND(404),//接口不存在
    NOT_SUPPORT(405),//请求方法不正确
    MISS_PARAM(400);//参数缺失

    private final int code;

    ResponseCode(int code) {
        this.code = code;
    }

    public int code() {
        return code;
    }
}

2. 定义返回信息

ResponseVo.java返回到客户端的·信息

public class ResponseVo {

    private int responseCode;
    private String responseMessage;

    public int getResponseCode() {
        return responseCode;
    }

    public ResponseVo setResponseCode(int responseCode) {
        this.responseCode = responseCode;
        return this;
    }

    public String getResponseMessage() {
        return responseMessage;
    }

    public ResponseVo setResponseMessage(String responseMessage) {
        this.responseMessage = responseMessage;
        return this;
    }

}

3. 自定义异常

这里自定义了两个异常

CustomException.java

package demo.srammy.exceptionhandler.exception;


import demo.srammy.exceptionhandler.vo.ResponseVo;

public class CustomException extends RuntimeException{
    private ResponseVo responseVo;

    public CustomException(ResponseVo responseVo) {
        this.responseVo = responseVo;
    }

    public ResponseVo getResponseVo() {
        return responseVo;
    }

    public void setResponseVo(ResponseVo responseVo) {
        this.responseVo = responseVo;
    }
}

MissQueryParameterException.java

public class MissQueryParameterException extends RuntimeException{
    private ResponseVo responseVo;

    public MissQueryParameterException(ResponseVo responseVo) {
        this.responseVo = responseVo;
    }

    public ResponseVo getResponseVo() {
        return responseVo;
    }

    public void setResponseVo(ResponseVo responseVo) {
        this.responseVo = responseVo;
    }
}

4. 统一异常处理

以JSON形式返回异常信息

@RestControllerAdvice
public class ExceptionControllerAdvice {
    @ExceptionHandler(Exception.class)
    public ResponseVo GlobalExceptionHandler(HttpServletRequest req, HttpServletResponse rsp, Exception e){
        ResponseVo rv = new ResponseVo();
        if (e instanceof CustomException) {
            rv = ((CustomException) e).getResponseVo();
        } else if (e instanceof MissQueryParameterException) {
            rv = ((MissQueryParameterException) e).getResponseVo();
        } else { // 处理其他异常，包括了404
            rv = rv.setResponseCode(ResponseCode.NOT_FOUND.code()).setResponseMessage("不存在");
        }

        return rv;
    }
}

5. 在controller中抛出异常

@RestController
public class UserController {

    @Autowired
    private UserService userService;

    @GetMapping(value = "/all")
    public List<User> getAllUsers() {
        throw new CustomException(new ResponseVo().setResponseCode(ResponseCode.NOT_SUPPORT.code()).setResponseMessage("请求错误"));
//        return userService.getAllUsers();
    }

    @GetMapping(value = "/finduser")
    public User findUserById(@RequestParam Integer id) {
        if (id == null) throw new MissQueryParameterException(new ResponseVo().setResponseCode(ResponseCode.MISS_PARAM.code()).setResponseMessage("缺少参数"));
        return userService.findUserById(id);
    }

}

6. 处理404等异常

404异常是不经过controller的。如果希望也已上面的方式对404进行异常处理，需要在配置文件中增加两行配置。

####### 异常处理 ######
# 为了处理404等异常
#没有绑定的url直接抛出错误
spring.mvc.throw-exception-if-no-handler-found=true
#不为静态文件建立映射
spring.resources.add-mappings=false

采用这样的配置之后，404异常也可以经过ExceptionControllerAdvice.java来进行处理