如何优雅地处理异常

前言

软件开发springboot项目过程中，不可避免的需要处理各种异常,spring mvc 架构中各层会出现大量的try catch finally 代码块，不仅有大量的冗余代码，而且还影响代码的可读性。这样就需要定义个全局统一异常处理器，以便业务层再也不必处理异常。

推荐理由

• 代码复制到项目中通过简单的配置即可实现
• 可以灵活的根据自己的业务异常进行更细粒度的扩展

实践

1 封装统一返回结果类

图片

源代码

public class AjaxResult {
    //是否成功
    private Boolean success;
    //状态码
    private Integer code;
    //提示信息
    private String msg;
    //数据
    private Object data;
    public AjaxResult() {

    }
    //自定义返回结果的构造方法
    public AjaxResult(Boolean success,Integer code, String msg,Object data) {
        this.success = success;
        this.code = code;
        this.msg = msg;
        this.data = data;
    }
    //自定义异常返回的结果
    public static AjaxResult defineError(BusinessException de){
        AjaxResult result = new AjaxResult();
        result.setSuccess(false);
        result.setCode(de.getErrorCode());
        result.setMsg(de.getErrorMsg());
        result.setData(null);
        return result;
    }
    //其他异常处理方法返回的结果
    public static AjaxResult otherError(ErrorEnum errorEnum){
        AjaxResult result = new AjaxResult();
        result.setMsg(errorEnum.getErrorMsg());
        result.setCode(errorEnum.getErrorCode());
        result.setSuccess(false);
        result.setData(null);
        return result;
    }
    public Boolean getSuccess() {
        return success;
    }
    public void setSuccess(Boolean success) {
        this.success = success;
    }
    public Integer getCode() {
        return code;
    }
    public void setCode(Integer code) {
        this.code = code;
    }
    public String getMsg() {
        return msg;
    }
    public void setMsg(String msg) {
        this.msg = msg;
    }
    public Object getData() {
        return data;
    }
    public void setData(Object data) {
        this.data = data;
    }

}

2 自定义异常封装类

源码：

public class BusinessException extends RuntimeException {
    private static final long serialVersionUID = 1L;
    /**     * 错误状态码     */
    protected Integer errorCode;
    /**     * 错误提示     */
    protected String errorMsg;

    public BusinessException(){

        }

    public BusinessException(Integer errorCode, String errorMsg) {
            this.errorCode = errorCode;
            this.errorMsg = errorMsg;
        }

    public Integer getErrorCode() {
        return errorCode;
    }

    public void setErrorCode(Integer errorCode) {
        this.errorCode = errorCode;
    }

    public String getErrorMsg() {
        return errorMsg;
    }

    public void setErrorMsg(String errorMsg) {
        this.errorMsg = errorMsg;
    }
}

3 错误枚举，拒绝硬编码

源码

public enum ErrorEnum {
    // 数据操作错误定义
    SUCCESS(200, "成功"),
    NO_PERMISSION(403,"你没得权限"),
    NO_AUTH(401,"未登录"),
    NOT_FOUND(404, "未找到该资源!"),
    INTERNAL_SERVER_ERROR(500, "服务器异常请联系管理员"),
    ;

    /** 错误码 */
    private Integer errorCode;

    /** 错误信息 */
    private String errorMsg;

    ErrorEnum(Integer errorCode, String errorMsg) {
        this.errorCode = errorCode;
        this.errorMsg = errorMsg;
    }

    public Integer getErrorCode() {
        return errorCode;
    }

    public String getErrorMsg() {
        return errorMsg;
    }
}

4 全局异常处理类

源码

/** * 全局异常处理器 *  */
@RestControllerAdvice
public class GlobalExceptionHandler
{
    private static final Logger log = LoggerFactory.getLogger(GlobalExceptionHandler.class);



    /**     * 处理自定义异常     *     */
    @ExceptionHandler(value = BusinessException.class)
    public AjaxResult bizExceptionHandler(BusinessException e) {
        log.error(e.getMessage(), e);
        return AjaxResult.defineError(e);
    }

    /**              *            处理其他异常     *     */
    @ExceptionHandler(value = Exception.class)
    public AjaxResult exceptionHandler( Exception e) {
         log.error(e.getMessage(), e);
        return AjaxResult.otherError(ErrorEnum.INTERNAL_SERVER_ERROR);

    }

}

5 测试

返回结果：