错误处理

几个要点：1、异常类，使用@ControllerAdvice注解，配合@ExceptionHandler注解处理各种异常。2、统一响应格式 3、统一异常枚举类

后台发生的所有错误，@ControllerAdvice + @ExceptionHandler进行统一异常处理。

1. 首先所有的异常被抛出来，都会进入到RestControllerAdvice里面被处理
2. 我们就在这里面对异常进行自定义处理（让spring能够感知异常让我们自己去处理）
3. 处理的话就需要给定响应结果（统一前后端 请求体 ）
4. 还需要定义异常的枚举类（对错误异常进行统一管理）

@RestControllerAdvice
@Slf4j
public class GlobalExceptionHandler {
    /**
     * Exception
     */
    @ExceptionHandler(value={Exception.class})
    public R exceptionHandle(HttpServletRequest req, Exception e) {
        String msg = StrUtil.sub(StrUtil.isEmpty(e.getMessage()) ? e.toString() : e.getMessage(), 0, 256);
        JSONObject jsonObject = new JSONObject();
        jsonObject.set("code", "E001");
        jsonObject.set("message", msg);
        log.error("请求 " + req.getRequestURL() + " 抛出异常： " + e);
        log.error(msg, e);
        return R.builder().code(500).message("异常：" + msg).data(jsonObject).build();
    }

    /**
     * 自定义业务异常
     */
    @ExceptionHandler(BusinessException.class)
    public R BusinessExceptionHandle(HttpServletRequest req, WorkSystemException e) {
        String msg = StrUtil.sub(StrUtil.isEmpty(e.getMessage()) ? e.toString() : e.getMessage(), 0, 256);
        JSONObject jsonObject = new JSONObject();
        jsonObject.set("code", e.getCode());
        jsonObject.set("message", msg);
        log.error("请求 " + req.getRequestURL() + " 抛出异常： " + e);
        log.error(msg, e);
        return R.builder().code(500).message("异常：" + msg).data(jsonObject).build();
    }
}

标准模板

统一响应格式R

import lombok.*;

import java.io.Serializable;

@Setter
@Getter
@Builder
@NoArgsConstructor
@AllArgsConstructor
public class R<T> implements Serializable {
    private static final long serialVersionUID = 111111111111111L;
    /**
     * 成功标记
     */
    static Integer SUCCESS = 0;
    /**
     * 失败标记
     */
    static Integer FAIL = 1;

    private int code;

    private String message;

    private T data;

    public static <T> R<T> success() {
        return restResult(null, SUCCESS, "操作成功");
    }

    public static <T> R<T> success(T data) {
        return restResult(data, SUCCESS, "操作成功");
    }

    public static <T> R<T> success(T data, String msg) {
        return restResult(data, SUCCESS, msg);
    }

    public static <T> R<T> failure() {
        return restResult(null, FAIL, "操作失败");
    }

    public static <T> R<T> failure(T data) {
        return restResult(data, FAIL, "操作失败");
    }

    public static <T> R<T> failure(T data, String msg) {
        return restResult(data, FAIL, msg);
    }

    private static <T> R<T> restResult(T data, int code, String msg) {
        return new R<>(code, msg, data);
    }
}

GlobalExceptionHandler

使用@ControllerAdvice注解，配合@ExceptionHandler注解处理各种异常。

import cn.hutool.core.util.StrUtil;
import cn.hutool.json.JSONObject;
import lombok.extern.slf4j.Slf4j;
import org.springframework.http.HttpStatus;
import org.springframework.validation.BindException;
import org.springframework.validation.FieldError;
import org.springframework.web.bind.MethodArgumentNotValidException;
import org.springframework.web.bind.annotation.ExceptionHandler;
import org.springframework.web.bind.annotation.ResponseStatus;
import org.springframework.web.bind.annotation.RestControllerAdvice;

import javax.servlet.http.HttpServletRequest;
import java.util.List;

@RestControllerAdvice
@Slf4j
public class GlobalExceptionHandler {
    /**
     * Exception
     */
    @ExceptionHandler(Exception.class)
    public R exceptionHandle(HttpServletRequest req, Exception e) {
        String msg = StrUtil.sub(StrUtil.isEmpty(e.getMessage()) ? e.toString():e.getMessage(), 0, 256);
        JSONObject jsonObject = new JSONObject();
        jsonObject.set("code", "E001");
        jsonObject.set("message", msg);
        log.error("请求 " + req.getRequestURL() + " 抛出异常： " + e);
        log.error(msg, e);
        return R.builder().code(500).message("异常：" + msg).data(jsonObject).build();
    }

    /**
     * 自定义业务异常
     */
    @ExceptionHandler(CustomException.class)
    public R CustomExceptionHandle(HttpServletRequest req, CustomException e) {
        String msg = StrUtil.sub(StrUtil.isEmpty(e.getMessage()) ? e.toString():e.getMessage(), 0, 256);
        JSONObject jsonObject = new JSONObject();
        jsonObject.set("code", e.getCode());
        jsonObject.set("message", msg);
        log.error("请求 " + req.getRequestURL() + " 抛出异常： " + e);
        log.error(msg, e);
        return R.builder().code(500).message("异常：" + msg).data(jsonObject).build();
    }

    /**
     * 处理业务校验过程中碰到的非法参数异常 该异常基本由{@link org.springframework.util.Assert}抛出
     *
     * @param exception 参数校验异常
     * @return API返回结果对象包装后的错误输出结果
     */
    @ExceptionHandler(IllegalArgumentException.class)
    @ResponseStatus(HttpStatus.OK)
    public R handleIllegalArgumentException(IllegalArgumentException exception) {
        log.error("非法参数,ex = {}", exception.getMessage(), exception);
        return R.failure(exception.getMessage());
    }

    /**
     * validation Exception
     *
     * @param exception
     * @return R
     */
    @ExceptionHandler({MethodArgumentNotValidException.class})
    @ResponseStatus(HttpStatus.BAD_REQUEST)
    public R handleBodyValidException(MethodArgumentNotValidException exception) {
        List<FieldError> fieldErrors = exception.getBindingResult().getFieldErrors();
        log.warn("参数绑定异常,ex = {}", fieldErrors.get(0).getDefaultMessage());
        return R.failure(fieldErrors.get(0).getDefaultMessage());
    }

    /**
     * validation Exception (以form-data形式传参)
     *
     * @param exception
     * @return R
     */
    @ExceptionHandler({BindException.class})
    @ResponseStatus(HttpStatus.BAD_REQUEST)
    public R bindExceptionHandler(BindException exception) {
        List<FieldError> fieldErrors = exception.getBindingResult().getFieldErrors();
        log.warn("参数绑定异常,ex = {}", fieldErrors.get(0).getDefaultMessage());
        return R.failure(fieldErrors.get(0).getDefaultMessage());
    }

}

异常枚举类

public enum CustomExceptionInfoEnum {

    /**
     * 系统通用异常 001~500
     */
    REQUEST_PARAM_MISS("001", "请求缺少接口必要参数：{0}"),
    UNKNOWN_EXCEPTION("002", "未知异常"),
    SYSTEM_RUN_EXCEPTION("003", "系统运行异常"),
    TIMEOUT("004", "超时"),
    DATA_FORMAT_ERR("005", "数据格式异常"),
    INTERFACE_MESSAGE_ERR("006", "接口通讯异常"),
    ;
    
    /**
     * 异常码
     */
    private String code;
    private String name;

    CustomExceptionInfoEnum(String code, String name) {
        this.code = code;
        this.name = name;
    }

}