文章链接

1. ssm入门
2. ssm框架进阶-----数据库增删改查
   3.ssm框架进阶-----数据库多表查询

正文

1.在model中创建ResponseCode

/**
 * 定义响应的状态码
 */
public enum ResponseCode {
    SUCCESS(100, "SUCCESS"),
    ERROR(101, "ERROR"),
    NEED_LOG(1, "NEED_LOG");
    private int code;
    private String desc;

    public int getCode() {
        return code;
    }

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

    public String getDesc() {
        return desc;
    }

    public void setDesc(String desc) {
        this.desc = desc;
    }

    ResponseCode(int code, String desc) {
        this.code = code;
        this.desc = desc;
    }
}

2.在model中创建ServerResponse

/**
* 封装后端返回的Json数据
*/

//保证序列化json时，如果是null的对象，key也会消失
@JsonInclude(JsonInclude.Include.NON_NULL)
public class ServerResponse<T> {

   //状态码
   private int statu;
   //数据
   private T data;
   //描述信息
   private String msg;

   //setter、getter方法
   public int getStatu() {
       return statu;
   }

   public void setStatu(int statu) {
       this.statu = statu;
   }

   public T getData() {
       return data;
   }

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

   public String getMsg() {
       return msg;
   }

   public void setMsg(String msg) {
       this.msg = msg;
   }
//构造函数

   /**
    * 操作成功时，返回数据
    *
    * @param statu
    * @param data
    * @param msg
    */
   public ServerResponse(int statu, T data, String msg) {
       this.statu = statu;
       this.data = data;
       this.msg = msg;
   }

   public ServerResponse(int statu) {
       this.statu = statu;
   }

   /**
    * 操作失败时，不返回数据
    *
    * @param statu
    * @param msg
    */
   public ServerResponse(int statu, String msg) {
       this.statu = statu;
       this.msg = msg;
   }

   //使之不在序列化结果中

   public boolean checkIsSuccess() {
       return this.statu == ResponseCode.SUCCESS.getCode();
   }

//泛型方法

   /**
    * 成功返回数据
    *
    * @param msg
    * @param data
    * @param <T>
    * @return
    */
   public static <T> ServerResponse<T> createBySuccess(String msg, T data) {
       return new ServerResponse<T>(ResponseCode.SUCCESS.getCode(), data, msg);
   }

   /**
    * 用于校验登录信息
    *
    * @param <T>
    * @return
    */
   public static <T> ServerResponse<T> createByCheckSuccess() {
       return new ServerResponse<T>(ResponseCode.SUCCESS.getCode());
   }

   /**
    * 返回错误信息
    *
    * @param msg
    * @param <T>
    * @return
    */
   public static <T> ServerResponse<T> createByError(String msg) {
       return new ServerResponse<T>(ResponseCode.ERROR.getCode(), msg);
   }

   public static <T> ServerResponse<T> createByNeedLogin() {
       return new ServerResponse<T>(ResponseCode.NEED_LOG.getCode(), "请先登录！");
   }

注：如果需要使用JsonInclude需要导包 在pom中导入

    <dependency>
            <groupId>com.fasterxml.jackson.core</groupId>
            <artifactId>jackson-databind</artifactId>
            <version>2.9.8</version>
        </dependency>

3.在UserService中修改接口

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