【Java Web】项目通用返回模块ServerResponse：枚举code状态码、泛型返回值、序列化注解限制数据

一、枚举类编写ResponseCode

package com.boulderaitech.common;

/**
 * 编写枚举类的步骤
 * （1）编写所需的变量
 * （2）编写枚举类构造方法
 * （3）编写枚举的值，调用构造方法，使用逗号隔开
 * （4）编写方法获取枚举类中对应的值
 */
public enum ResponseCode {
    //（3）编写枚举的值，调用构造方法，使用逗号隔开
    SUCCESS(0,"SUCCESS"),
    ERROR(1,"ERROR");
    //（1）编写所需的变量
    private final int code;
    private final String desc;
    //（2）编写枚举类构造方法
    ResponseCode(int code,String desc) {
        this.code=code;
        this.desc=desc;
    }
    //（4）编写方法获取枚举类中对应的值
    public int getCode() {
        return code;
    }
    public String getDesc() {
        return desc;
    }
}

二、含泛型的通用返回类ServerResponse

package com.boulderaitech.common;

import com.fasterxml.jackson.databind.annotation.JsonSerialize;

import java.io.Serializable;

//用于封装数据的类，加泛型实现序列化接口
//通过注解约束其序列化方式，即非空的类不允许序列化
@JsonSerialize(include = JsonSerialize.Inclusion.NON_NULL)
public class ServerResponse<T> implements Serializable {
    private int status;
    private String msg;
    private T data;
    //编写不同的构造方法，更改为private，禁止外部创建该类的对象
    private ServerResponse(int status) {
        this.status = status;
    }

    private ServerResponse(int status, String msg) {
        this.status = status;
        this.msg = msg;
    }

    private ServerResponse(int status, T data) {
        this.status = status;
        this.data = data;
    }

    private ServerResponse(int status, String msg, T data) {
        this.status = status;
        this.msg = msg;
        this.data = data;
    }
    //提供get方法，后续要返回json数据，没有get方法无法返回数据
    public int getStatus() {
        return status;
    }

    public String getMsg() {
        return msg;
    }

    public T getData() {
        return data;
    }
    //在内部提供静态方法供外部访问
    public static <T> ServerResponse<T> createSuccess() {
        return new ServerResponse<>(ResponseCode.SUCCESS.getCode());
    }
    public static <T> ServerResponse<T> createSuccessMsg(String msg) {
        return new ServerResponse<>(ResponseCode.SUCCESS.getCode(),msg);
    }
    public static <T> ServerResponse<T> createSuccessData(T data) {
        return new ServerResponse<>(ResponseCode.SUCCESS.getCode(),data);
    }
    public static <T> ServerResponse<T> createSuccessMsgData(String msg,T data) {
        return new ServerResponse<>(ResponseCode.SUCCESS.getCode(),msg,data);
    }
    public static <T> ServerResponse<T> createErrorMsg(String errorMsg) {
        return new ServerResponse<>(ResponseCode.ERROR.getCode(),errorMsg);
    }

}