hibernate关联关系注解（一对多、多对一、一对一）

Myth丶恋晨 2022-08-23 09:54 187阅读 0赞

一对多、多对一、一对一的注解实现

casecade=\{CasecadeType.REFRESH\}的含义是只是查询级联，它还有其他3个类型：

CascadeType.MERGE级联更新

CascadeType.PERSIST级联保存

CascadeType.REMOVE级联删除

optional=false定义关联类不一定要存在

@JoinColumn 关联的对象的字段

@ManyToOne多对一   @OneToMany一对多 @OneToOne一对一

需要注意的是一对一关联关系，hibernate会建立唯一约束，用错的话，后果很严重奥。

event对象

@Entity
    @Table(name = "event")
    public class EventEntity implements Serializable{
    	/**
    	 * 
    	 */
    	private static final long serialVersionUID = 1L;
    	@Id
    	@GeneratedValue(strategy = GenerationType.IDENTITY)
    	@Column(name = "eventId", nullable = true)
    	private long eventId;               //事件id
    	private String eventNote;           //事件内容
    	private String eventTitle;          //事件标题
    	private String createTime;          //创建时间
    	@ManyToOne(cascade = {CascadeType.REFRESH}, optional = false)
    	@JoinColumn(name="userId")
    	private UserEntity user;
    	@OneToOne(optional = false, cascade = CascadeType.REFRESH)
    	@JoinColumn(name = "eventTitleImage")
    	private EventImageEntity eventTitleImage;  //事件封面照片
    	private String eventAddress;       //事件地址
    	private String eventType;          //事件类型
    	private String lon;                //经度
    	private String lat;                //纬度
    	private String eventstate;         //事件状态
    	@OneToMany(cascade = {CascadeType.REFRESH})
    	@JoinColumn(name = "eventId")
            private List<EventImageEntity> eventImageList;
    	public long getEventId() {
    		return eventId;
    	}
    
    	public void setEventId(long eventId) {
    		this.eventId = eventId;
    	}
    
    	public String getEventNote() {
    		return eventNote;
    	}
    
    	public void setEventNote(String eventNote) {
    		this.eventNote = eventNote;
    	}
    
    	public String getEventTitle() {
    		return eventTitle;
    	}
    
    	public void setEventTitle(String eventTitle) {
    		this.eventTitle = eventTitle;
    	}
    
    	 public String getCreateTime() {
    		return createTime;
    	}
    
    	public void setCreateTime(String createTime) {
    		this.createTime = createTime;
    	}
    
    	public UserEntity getUser() {
    		return user;
    	}
    
    	public void setUser(UserEntity user) {
    		this.user = user;
    	}
    
    	public EventImageEntity getEventTitleImage() {
    		return eventTitleImage;
    	}
    
    	public void setEventTitleImage(EventImageEntity eventTitleImage) {
    		this.eventTitleImage = eventTitleImage;
    	}
    
    	public String getEventAddress() {
    		return eventAddress;
    	}
    
    	public void setEventAddress(String eventAddress) {
    		this.eventAddress = eventAddress;
    	}
    
    	public String getEventType() {
    		return eventType;
    	}
    
    	public void setEventType(String eventType) {
    		this.eventType = eventType;
    	}
    
    	public String getLon() {
    		return lon;
    	}
    
    	public void setLon(String lon) {
    		this.lon = lon;
    	}
    
    	public String getLat() {
    		return lat;
    	}
    
    	public void setLat(String lat) {
    		this.lat = lat;
    	}
    
    	public String getEventstate() {
    		return eventstate;
    	}
    
    	public void setEventstate(String eventstate) {
    		this.eventstate = eventstate;
    	}
    
    	public List<EventImageEntity> getEventImageList() {
    		return eventImageList;
    	}
    
    	public void setEventImageList(List<EventImageEntity> eventImageList) {
    		this.eventImageList = eventImageList;
    	}
    
    }

user对象

@Entity
    @Table(name = "user")
    public class UserEntity implements Serializable {
    	/**
    	 * 
    	 */
    	private static final long serialVersionUID = 1L;
    	@Id
    	@GeneratedValue(strategy = GenerationType.IDENTITY)
    	@Column(name = "userId")
    	private long userId;
    	private String username;   //用户名称   
    	private String phone;      //用户电话
    	private String password;   //密码
    	@OneToOne(optional = false, cascade = CascadeType.REFRESH)
    	@JoinColumn(name = "userimage")
    	private ImageEntity userImage;  //用户头像
    	private String isRole;          //是否有权限
    	private String createTime;      //创建时间
    	private String sign;            //签名
    	private String sex;             //性别
    	private String age;             //年纪
    	private String birthday;        //生日
    	private String numberId;        //用户ID标示
    	private String emotional;		//情感状态
    	private String updateTime;      //修改时间
    	private String userstate;       //用户状态（1正常 2禁用 3删除）
    	@ManyToOne(cascade={CascadeType.REFRESH},optional = false)
    	@JoinColumn(name="userLevel")
            private Exp exp;                //等级
    	private long exping;            //当前经验值
    	public long getUserId() {
    		return userId;
    	}
    
    	public void setUserId(long userId) {
    		this.userId = userId;
    	}
    
    	public String getUsername() {
    		return username;
    	}
    
    	public void setUsername(String username) {
    		this.username = username;
    	}
    
    
    	public String getPhone() {
    		return phone;
    	}
    
    	public void setPhone(String phone) {
    		this.phone = phone;
    	}
    
    	public String getPassword() {
    		return password;
    	}
    
    	public void setPassword(String password) {
    		this.password = password;
    	}
    
    	public ImageEntity getUserImage() {
    		return userImage;
    	}
    
    	public void setUserImage(ImageEntity userImage) {
    		this.userImage = userImage;
    	}
    
    	public String getIsRole() {
    		return isRole;
    	}
    
    	public void setIsRole(String isRole) {
    		this.isRole = isRole;
    	}
    
    	public String getCreateTime() {
    		return createTime;
    	}
    
    	public void setCreateTime(String createTime) {
    		this.createTime = createTime;
    	}
    
    	public String getSign() {
    		return sign;
    	}
    
    	public void setSign(String sign) {
    		this.sign = sign;
    	}
    
    	public String getSex() {
    		return sex;
    	}
    
    	public void setSex(String sex) {
    		this.sex = sex;
    	}
    
    	public String getAge() {
    		return age;
    	}
    
    	public void setAge(String age) {
    		this.age = age;
    	}
    
    	public String getBirthday() {
    		return birthday;
    	}
    
    	public void setBirthday(String birthday) {
    		this.birthday = birthday;
    	}
    
    	public String getNumberId() {
    		return numberId;
    	}
    
    	public void setNumberId(String numberId) {
    		this.numberId = numberId;
    	}
    
    	public String getEmotional() {
    		return emotional;
    	}
    
    	public void setEmotional(String emotional) {
    		this.emotional = emotional;
    	}
    
    	public String getUpdateTime() {
    		return updateTime;
    	}
    
    	public void setUpdateTime(String updateTime) {
    		this.updateTime = updateTime;
    	}
    
    	public String getUserstate() {
    		return userstate;
    	}
    
    	public void setUserstate(String userstate) {
    		this.userstate = userstate;
    	}
    
    	public Exp getExp() {
    		return exp;
    	}
    
    	public void setExp(Exp exp) {
    		this.exp = exp;
    	}
    
    	public long getExping() {
    		return exping;
    	}
    
    	public void setExping(long exping) {
    		this.exping = exping;
    	}
    
    }

image对象

@Entity
    @Table(name = "image")
    public class ImageEntity implements Serializable{
    	/**
    	 * 
    	 */
    	private static final long serialVersionUID = 1L;
    	@Id
    	@GeneratedValue(strategy = GenerationType.IDENTITY)
    	@Column(name = "imageId")
    	private long imageId;
    	private String url;
    
    	public long getImageId() {
    		return imageId;
    	}
    
    	public void setImageId(long imageId) {
    		this.imageId = imageId;
    	}
    
    	public String getUrl() {
    		return url;
    	}
    
    	public void setUrl(String url) {
    		this.url = url;
    	}
    
    }

exp对象

@Entity
    @Table(name = "exp")
    public class Exp {
    	@Id
    	@GeneratedValue(strategy = GenerationType.IDENTITY)
    	@Column(name = "expId")
        private long expId;
        private long grade;     //等级
        private long expnumber; //经验值
        private String expname; //显示名称
    	public long getExtId() {
    		return expId;
    	}
    	public void setExtId(long expId) {
    		this.expId = expId;
    	}
    	public long getGrade() {
    		return grade;
    	}
    	public void setGrade(long grade) {
    		this.grade = grade;
    	}
    	public long getExpnumber() {
    		return expnumber;
    	}
    	public void setExpnumber(long expnumber) {
    		this.expnumber = expnumber;
    	}
    	public String getExpname() {
    		return expname;
    	}
    	public void setExpname(String expname) {
    		this.expname = expname;
    	}
        
    }

eventImage对象

@Entity
    @Table(name = "eventimage")
    public class EventImageEntity implements Serializable{
    	/**
    	 * 
    	 */
    	private static final long serialVersionUID = 1L;
    	@Id
    	@GeneratedValue(strategy = GenerationType.IDENTITY)
    	@Column(name = "eventImageId")
    	private long eventImageId;
    	private long eventId;
    	@OneToOne(optional = false, cascade = CascadeType.REFRESH)
    	@JoinColumn(name = "imageId")
    	private ImageEntity image;
    	public long getEventImageId() {
    		return eventImageId;
    	}
    	public void setEventImageId(long eventImageId) {
    		this.eventImageId = eventImageId;
    	}
    	public long getEventId() {
    		return eventId;
    	}
    	public void setEventId(long eventId) {
    		this.eventId = eventId;
    	}
    	public ImageEntity getImage() {
    		return image;
    	}
    	public void setImage(ImageEntity image) {
    		this.image = image;
    	}
    	
    }