code enum:

import java.io.Serializable;

/**
 * @author tong.luo
 * @description RetVO
 * @date 2021/3/8 17:07
 */
public class RetVO<T> implements Serializable {
    private static final long serialVersionUID = 4087908700685218023L;

    private String code;
    private String msg;
    private T data;

    public RetVO() {
    }

    private RetVO(String code, String msg, T data) {
        this.code = code;
        this.msg = msg;
        this.data = data;
    }

    private RetVO(String code, String msg) {
        this.code = code;
        this.msg = msg;
    }

    private RetVO(T data) {
        this.code = SysEnum.SUCCESS.getCode();
        this.msg = SysEnum.SUCCESS.getMsg();
        this.data = data;
    }

    public static <T> RetVO<T> success(T data) {
        return new RetVO<>(data);
    }

    public static <T> RetVO<T> error(String msg, String code) {
        return new RetVO<>(SysEnum.SUCCESS.getCode(), msg);
    }

    public static <T> RetVO<T> error(SysEnum sysEnum) {
        return new RetVO<>(sysEnum.getCode(), sysEnum.getMsg());
    }

    public String getCode() {
        return code;
    }

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

    public String getMsg() {
        return msg;
    }

    public void setMsg(String msg) {
        this.msg = msg;
    }

    public T getData() {
        return data;
    }

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

public enum SysEnum {
    SUCCESS("200","success"),
    error("500","server error"),
    ;
    private String code;
    private String msg;

    SysEnum(String code, String msg) {
        this.code = code;
        this.msg = msg;
    }

    public String getCode() {
        return code;
    }

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

    public String getMsg() {
        return msg;
    }

    public void setMsg(String msg) {
        this.msg = msg;
    }
}

/**
 * @author tong.luo
 * @description BusinessException
 * @date 2021/3/8 17:14
 */
public class BusinessException extends RuntimeException {
    private static final long serialVersionUID = -6733364661567308818L;
    private Integer code;
    private String message;

    public BusinessException(String message) {
        super(message);
        this.message = message;
    }

    public BusinessException(Integer code, String msg) {
        super(msg);
        this.code = code;
        this.message = msg;
    }

    public Integer getCode() {
        return code;
    }

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

    @Override
    public String getMessage() {
        return message;
    }

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