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javabean?中使用@Transient屬性處理臨時(shí)字段

更新時(shí)間：2023年08月14日 09:22:17 作者：明月一壺酒

@Transient表示該屬性并非一個(gè)到數(shù)據(jù)庫(kù)表的字段的映射,ORM框架將忽略該屬性,本文給大家介紹javabean?中臨時(shí)字段的處理：@Transient,感興趣的朋友跟隨小編一起看看吧

當(dāng)我們使用spring data jpa開(kāi)發(fā)的時(shí)候，會(huì)將實(shí)體類中的成員變量與表中的字段一一對(duì)應(yīng)，當(dāng)我們?cè)趯?shí)體類中加上一個(gè)數(shù)據(jù)庫(kù)表沒(méi)有對(duì)應(yīng)字段的成員變量的時(shí)候，此時(shí)我們只要在這個(gè)成員變量上加上注解@Transient

@Transient表示該屬性并非一個(gè)到數(shù)據(jù)庫(kù)表的字段的映射,ORM框架將忽略該屬性. 如果一個(gè)屬性并非數(shù)據(jù)庫(kù)表的字段映射,務(wù)必將其標(biāo)示為@Transient,否則,ORM框架默認(rèn)其注解為@Basic比如現(xiàn)在有實(shí)體類Message,但是我想在使用它時(shí)想要多用一個(gè)字段來(lái)接收未讀消息的數(shù)量 unReadCount，此時(shí)只要在字段前加上@Transient注解就可以了。當(dāng)數(shù)據(jù)庫(kù)表字段與result不一致時(shí)用@Column注解

依賴包

import javax.persistence.Transient;

代碼

package com.xy.base.domain;
import lombok.Data;
import javax.persistence.Column;
import javax.persistence.Id;
import javax.persistence.Table;
import javax.persistence.Transient;
import java.util.Date;
import java.util.List;
@Entity
@Table(name = "T_SS_LLJLB")
@Data
@Accessors(chain = true)
public class TSsLljlb extends BaseEntity {
    public static final String TABLE = "T_SS_LLJLB";
    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    @Column(name = "id", nullable = false)
    private Integer id;
    @ApiModelProperty(value = "操作人")
    @Column(name = "user_id", length = 50)
    private String userId;
    @ApiModelProperty(value = "攝像機(jī)ID")
    @Column(name = "camera_id", length = 50)
    private String cameraId;
    @ApiModelProperty(value = "攝像機(jī)名稱")
    @Column(name = "camera_name", length = 50)
    private String cameraName;
    @ApiModelProperty(value = "設(shè)備ID")
    @Column(name = "device_id", length = 50)
    private String deviceId;
    @ApiModelProperty(value = "通道ID")
    @Column(name = "channel_id", length = 50)
    private String channelId;
    @ApiModelProperty(value = "線路編碼")
    @Column(name = "line_code", length = 50)
    private String lineCode;
    @ApiModelProperty(value = "線路名稱")
    @Column(name = "line_name", length = 50)
    private String lineName;
    @ApiModelProperty(value = "操作類型，1-拉流 0-關(guān)流")
    @Column(name = "operation")
    private Integer operation;
    @ApiModelProperty(value = "拉流時(shí)間(頁(yè)面請(qǐng)求視頻流的時(shí)間)")
    @Column(name = "pull_time")
    @JsonFormat(pattern = "yyyy-MM-dd HH:mm:ss", timezone = "GMT+8")
    private Date pullTime;
    @ApiModelProperty(value = "推流時(shí)間(頁(yè)面獲取視頻URL的時(shí)間)")
    @Column(name = "push_time")
    @JsonFormat(pattern = "yyyy-MM-dd HH:mm:ss", timezone = "GMT+8")
    private Date pushTime;
    @ApiModelProperty(value = "頁(yè)面關(guān)流時(shí)間(頁(yè)面請(qǐng)求關(guān)閉視頻流的時(shí)間)")
    @Column(name = "page_close_time")
    @JsonFormat(pattern = "yyyy-MM-dd HH:mm:ss", timezone = "GMT+8")
    private Date pageCloseTime;
    @ApiModelProperty(value = "服務(wù)關(guān)流時(shí)間(分轉(zhuǎn)發(fā)服務(wù)實(shí)際關(guān)閉視頻流的時(shí)間)")
    @Column(name = "service_close_time")
    @JsonFormat(pattern = "yyyy-MM-dd HH:mm:ss", timezone = "GMT+8")
    private Date serviceCloseTime;
    @ApiModelProperty(value = "取流狀態(tài)(取流成功-200，取流失敗-報(bào)錯(cuò)編碼)")
    @Column(name = "status")
    private Integer status;
    @ApiModelProperty(value = "創(chuàng)建記錄時(shí)間")
    @Column(name = "create_time")
    @JsonFormat(pattern = "yyyy-MM-dd HH:mm:ss", timezone = "GMT+8")
    private Date createTime;
    @ApiModelProperty(value = "更新記錄時(shí)間")
    @Column(name = "update_time")
    @JsonFormat(pattern = "yyyy-MM-dd HH:mm:ss", timezone = "GMT+8")
    private Date updateTime;
    @ApiModelProperty(value = "臨時(shí)記錄攝像頭拉流次數(shù)")
    @Transient
    private Integer num;
    public TSsLljlb initTSsLljlb(TSsLljlb tSsLljlb) {
        return this.setCreateTime(new Date());
    }
}

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