JAVA高级面试进阶训练营视频教程

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首先，返回有两个状态，status和code

status标识response的状态，有2个值：0成功，-1服务错误。

code跟业务有关，可以有各种数值，99999服务未知异常，10000参数异常，100001创建订单失败等等。这两个状态用枚举类表示。

ResponseStatus

/**
 * @Author: ivan
 * @Description: 服务状态代码
 * @Date: 18/11/26
 * @Modified By;
 */
public enum ResponseStatus {

    OK(0, "成功"),
    ERROR(-1, "服务错误");

    private int value;
    private String message;

    ResponseStatus(int value, String message){
        this.value = value;
        this.message = message;
    }

    public int getValue() {
        return value;
    }

    public String getMessage() {
        return message;
    }

}

 

 

ResponseCode

/**
 * @Author: ivan
 * @Description: 业务状态代码
 * @Date: 18/11/26
 * @Modified By;
 */
public enum ResponseCode {

    FORMAL(0, "业务正常"),
    INVALID_PARAM(100000, "参数错误"),
    UNKNOWN_FAILED(999999, "服务器未知错误"),
    SAVE_FAILED(888888, "保存失败"),
    UPDATE_FAILED(777777, "保存失败"),
    DELTE_FAILED(666666, "删除失败"),
    SEARCH_FLOW_FAILED(555555, "查询任务流的执行详情失败!");

    private int value;
    private String message;

    ResponseCode(int value, String message){
        this.value = value;
        this.message = message;
    }

    public int getValue() {
        return value;
    }

    public String getMessage() {
        return message;
    }

}

 

然后，是Response类，简单工厂模式，提供build方法，创建正常返回和错误返回Response。

Response

/**
 * @Author: ivan
 * @Description: 返回值封装
 * @Date: Created in 17:26 18/11/26
 * @Modified By:
 */
public class Response<T> implements Serializable {

    private int status;

    private int code;

    private String message;

    private Object data;

    public Response(ResponseStatus status, ResponseCode code, String message, T data) {
        this.setStatus(status);
        this.setCode(code);
        this.setMessage(message);
        this.setData(data);
    }

    public static <T> Response<T> buildSuccessResponse(T data) {
        return new Response<T>(ResponseStatus.OK, ResponseCode.FORMAL, null, data);
    }

    public static <T> Response<T> buildFailResponse(ResponseStatus responseStatus, ResponseCode responseCode,
                                                  String message, T data) {
        return new Response<T>(responseStatus, responseCode, message, data);
    }


    public int getStatus() {
        return status;
    }

    public void setStatus(ResponseStatus status) {
        this.status = status.getValue();
    }

    public int getCode() {
        return code;
    }

    public void setCode(ResponseCode code) {
        this.code = code.getValue();
    }

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

    public Object getData() {
        return data;
    }

    public void setData(Object data) {
        this.data = data;
    }
}

 

如果不想在controller里try-catch一般的异常，并且在一定的条件下通过throw控制代码逻辑，我们需要建立ControllerAdvice。

我这个advice会捕捉ApiException(自定义)，一般用业务Code码里的错误码和信息，这时候我们可以返回提示性异常。然后就是Exception普通异常，一般提示服务器未知错误。

我这里还处理了一个参数校验异常

/**
 * @Author: ivan
 * @Description: 全局异常处理advice
 * @Date: Created in 20:21 18/11/26
 * @Modified By:
 */
@ControllerAdvice
public class GlobalExceptionHandler {

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

    /**
    *   处理全局异常handler, ApiException为业务异常, 其他为服务器未知异常
    */
    @ExceptionHandler(Exception.class)
    @ResponseBody
    public Response<String> handle(Exception e) {

        Response<String> response;

        if (e instanceof ApiException) {
            ApiException error = (ApiException) e;
            response = Response.buildFailResponse(ResponseStatus.ERROR, error.getResponseCode(),
                    error.getResponseCode().getMessage(), null);
        } else {
            response = Response.buildFailResponse(ResponseStatus.ERROR, ResponseCode.UNKNOWN_FAILED,
                    ResponseCode.UNKNOWN_FAILED.getMessage(), null);
        }

        logger.error("[Exception] message={}", e);

        return response;
    }


    /**
     *  处理参数校验异常handler
     */
    @ExceptionHandler(ValidationException.class)
    @ResponseBody
    public Response<String> handle(ValidationException e) {

        StringBuilder sb = new StringBuilder();

        if(e instanceof ConstraintViolationException){

            ConstraintViolationException error = (ConstraintViolationException) e;
            Set<ConstraintViolation<?>> violations = error.getConstraintViolations();

            for (ConstraintViolation<?> item : violations) {
                sb.append(item.getMessage());
            }

        }

        logger.error("[Validation] message={}", sb.toString(), e);

        return Response.buildFailResponse(ResponseStatus.ERROR, ResponseCode.INVALID_PARAM, sb.toString(), null);

    }

}