Question

我有一个Job类，如下所示

@Id
@GeneratedValue(strategy=GenerationType.IDENTITY)
public int getId() {
    return Id;
}
public void setId(int id) {
    Id = id;
}

@ManyToOne(fetch = FetchType.LAZY, cascade=CascadeType.PERSIST)
@NotNull
@JoinColumn(name="job_type_id")
public JobType getJobType() {
    return jobType;
}

public void setJobType(JobType jobType) {
    this.jobType = jobType;
}

@ManyToOne(fetch = FetchType.LAZY, cascade=CascadeType.PERSIST)
@NotNull
@JoinColumn(name="job_status_id")
public JobStatus getJobStatus() {
    return jobStatus;
}
public void setJobStatus(JobStatus jobStatus) {
    this.jobStatus = jobStatus;
}


@Column(name="priority",nullable=false)
public int getPriority() {
    return priority;
}
public void setPriority(int priority) {
    this.priority = priority;
}

@ManyToOne(fetch = FetchType.LAZY, cascade=CascadeType.PERSIST)
@NotNull
@JoinColumn(name="applliaction_id")
public Application getApplication() {
    return application;
}
public void setApplication(Application application) {
    this.application = application;
}

}

JobStatus类就像

@Id
@GeneratedValue(strategy=GenerationType.IDENTITY)
public int getId() {
    return id;
}
public void setId(int id) {
    this.id = id;
}

@Column(name="name",nullable =false, unique=true, length=50)
public String getName() {
    return name;
}
public void setName(String name) {
    this.name = name;
}

@Column(name="description",columnDefinition = "text")
public String getDescription() {
    return description;
}
public void setDescription(String description) {
    this.description = description;
}

和JobType类一样

    @Id
@GeneratedValue(strategy=GenerationType.IDENTITY)
public int getId() {
    return id;
}

public void setId(int id) {
    this.id = id;
}

@Column(name="name", unique=true, nullable=false,length=20)
public String getName() {
    return name;
}
public void setName(String name) {
    this.name = name;
}

@Column(name="description",columnDefinition = "text")
public String getDescription() {
    return description;
}
public void setDescription(String description) {
    this.description = description;
}

和应用程序类如

@Id
@GeneratedValue(strategy=GenerationType.IDENTITY)
public int getId() {
    return id;
}
public void setId(int id) {
    this.id = id;
}

@Column(name="name",nullable=false,unique =true, length=50)
public String getName() {
    return name;
}
public void setName(String name) {
    this.name = name;
}

@Column(name="current_version",nullable=false,length=50)
public String getCurretnVersion() {
    return curretnVersion;
}
public void setCurretnVersion(String curretnVersion) {
    this.curretnVersion = curretnVersion;
}

@Column(name="updated_at",nullable=false)
public Date getUpdatedAt() {
    return updatedAt;
}
public void setUpdatedAt(Date updatedAt) {
    this.updatedAt = updatedAt;
}

@Column(name="created_at",nullable=false)
public Date getCreatedAt() {
    return createdAt;
}
public void setCreatedAt(Date createdAt) {
    this.createdAt = createdAt;
}
@Column(name="description",columnDefinition = "text")
public String getDescription() {
    return description;
}
public void setDescription(String description) {
    this.description = description;
}

主要方法就像

public static void main(String[] args) {
    System.out.println((new SimpleDateFormat("HH:mm:ss:SSS")).format(new Date()));      
    Session session = HibernateUtil.getSessionFactory().openSession();
    System.out.println((new SimpleDateFormat("HH:mm:ss:SSS")).format(new Date()));

    //Application
    Application app = new Application();
    app.setName("GW");
    app.setCreatedAt(new Date());
    app.setUpdatedAt(new Date());
    app.setCurretnVersion("1.0");

    //Job Type
    JobType jType = new JobType();
    jType.setDescription("new type");
    jType.setName("banboo");

    //Job Status
    JobStatus js = new JobStatus();
    js.setName("waiting");


    //first job
    Job job1 = new Job();
    job1.setPriority(3);        
    job1.setApplication(app);
    job1.setJobType(jType);
    job1.setJobStatus(js);

    //Second Job
    Job job2 = new Job();
    job2.setPriority(3);
    job2.setApplication(app);
    job2.setJobStatus(js);
    job2.setJobType(jType);

    Transaction tx = session.beginTransaction();
    session.save(job1);
    session.save(job2);
    session.save(jType);
    session.save(js);
    session.save(app);
    tx.commit();
    session.close();
    System.out.println((new SimpleDateFormat("HH:mm:ss:SSS")).format(new Date()));
}

我第一次跑主要是OK。但是当我重新运行时。得到以下错误。重复键值违反唯一约束“uk_jidxac21t4vg1tmees14dwyo1” 细节：键（名称）=（banboo）已经存在。

如何解决问题？

谢谢，

斯科特

按照JB Nizet的建议编辑程序和问题。

Answer 1

你告诉Hibernate该关联是OneToOne。

这意味着只有一个Job可以引用给定的JobStatus，并且给定的Job只能引用一个JobStatus。

如果您想要多个职位共享一个JobStatus，则需要ManyToOne。

Hibernate ManyToOne引用一个具有列的对象（unique = true）？

1 个答案: