SpringMvc建立统一异常处理

1.异常处理作用

统一的异常处理可以让前台隔离那些对他们无需的信息,但是又让后台可以很好的规避泛滥的异常.

2.代码示例:

1. 建立业务异常

/**
 * 服务(业务)异常如"账号或密码错误",该异常只做INFO级别的日志记录
 *
 * @see com.ley.springboot.seed.config.WebConfig
 */
public class ServiceException extends RuntimeException {

    public ServiceException() {
    }

    public ServiceException(String message) {
        super(message);
    }

    public ServiceException(String message, Throwable cause) {
        super(message, cause);
    }
}

2.建立web相应封装

/**
 * 统一API响应结果封装
 */
public class Result<T> {

    /**
     * response code
     **/
    private int code;

    /**
     * response message
     **/
    private String message;

    /**
     * response data
     **/
    private T data;

    public Result setCode(ResultCode resultCode) {
        this.code = resultCode.code();
        return this;
    }

    public int getCode() {
        return code;
    }

    public String getMessage() {
        return message;
    }

    public Result setMessage(String message) {
        this.message = message;
        return this;
    }

    public T getData() {
        return data;
    }

    public Result setData(T data) {
        this.data = data;
        return this;
    }

    @Override
    public String toString() {
        return JSON.toJSONString(this);
    }
}

/**
 * 响应码枚举,参考HTTP状态码的语义
 *
 * @see org.springframework.http.HttpStatus
 */
public enum ResultCode {

    SUCCESS(200),//成功
    FAIL(400),//失败
    UNAUTHORIZED(401),//未认证(签名错误)
    NOT_FOUND(404),//接口不存在
    INTERNAL_SERVER_ERROR(500);//服务器内部错误

    private final int code;

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

    public int code() {
        return code;
    }
}

3.统一异常处理

/**
 * web config
 **/
@Configuration
public class WebConfig extends WebMvcConfigurerAdapter {

    private final Logger logger = LoggerFactory.getLogger(WebConfig.class);


    @Override
    public void configureMessageConverters(List<HttpMessageConverter<?>> converters) {
        FastJsonHttpMessageConverter converter = new FastJsonHttpMessageConverter();
        FastJsonConfig config = new FastJsonConfig();
        config.setSerializerFeatures(SerializerFeature.WriteNullStringAsEmpty, SerializerFeature.WriteNullNumberAsZero);

        // 按需配置,更多参考FastJson文档
        converter.setFastJsonConfig(config);
        converter.setDefaultCharset(Charset.forName("UTF-8"));
        converter.setSupportedMediaTypes(Arrays.asList(MediaType.APPLICATION_JSON_UTF8));
        converters.add(converter);
    }


    //统一异常处理
    @Override
    public void configureHandlerExceptionResolvers(List<HandlerExceptionResolver> exceptionResolvers) {
        exceptionResolvers.add(new HandlerExceptionResolver() {
            public ModelAndView resolveException(HttpServletRequest request, HttpServletResponse response, Object handler, Exception e) {
                Result result = new Result();
                if (e instanceof ServiceException) {//业务失败的异常,如"账号或密码错误"
                    result.setCode(ResultCode.FAIL).setMessage(e.getMessage());
                    logger.info(e.getMessage());
                } else if (e instanceof NoHandlerFoundException) {
                    result.setCode(ResultCode.NOT_FOUND).setMessage("接口 [" + request.getRequestURI() + "] 不存在");
                } else if (e instanceof ServletException) {
                    result.setCode(ResultCode.FAIL).setMessage(e.getMessage());
                } else {
                    result.setCode(ResultCode.INTERNAL_SERVER_ERROR).setMessage("接口 [" + request.getRequestURI() + "] 内部错误，请联系管理员");
                    String message;
                    if (handler instanceof HandlerMethod) {
                        HandlerMethod handlerMethod = (HandlerMethod) handler;
                        message = String.format("接口 [%s] 出现异常，方法：[%s.%s]，异常摘要：%s",
                                request.getRequestURI(),
                                handlerMethod.getBean().getClass().getName(),
                                handlerMethod.getMethod().getName(),
                                e.getMessage());
                    } else {
                        message = e.getMessage();
                    }
                    // result.setMessage(message);
                    logger.error(message, e);
                }
                responseResult(response, result);
                return new ModelAndView();
            }

        });
    }


    private void responseResult(HttpServletResponse response, Result result) {
        response.setCharacterEncoding("UTF-8");
        response.setHeader("Content-type", "application/json;charset=UTF-8");
        response.setStatus(HttpStatus.OK.value());
        try {
            response.getWriter().write(JSON.toJSONString(result));
        } catch (IOException ex) {
            logger.error(ex.getMessage());
        }
    }
}