UUID as key

msi_333 · **Posted:** Sat Apr 17, 2010 9:06 pm

Following code is any example of UUID default until java class to generate a UUID as primary key in JPA entity .The idea is so simple , just set the value of UUID to the primary key before the persistence .

Here is the entity :

Code:

package com.codemiles.jpa;
import java.util.Date;

import javax.persistence.Column;
import javax.persistence.Entity;
import javax.persistence.Id;
import javax.persistence.Table;


@Entity
@Table(name="TOPIC")
public class Topic implements java.io.Serializable{
    /**
     * 
     */
    private static final long serialVersionUID = 1L;
    @Id
    private String Id;
    private String title;
    private Date creationDate;
    private Date modifedDate;
    private String content;
    

    public String getId() {
        return Id;
    }
    public void setId(String id) {
        Id = id;
    }
    
    @Column(name="TITLE")
    public String getTitle() {
        return title;
    }
    public void setTitle(String title) {
        this.title = title;
    }
    
    @Column(name="CREATION_DATE")
    public Date getCreationDate() {
        return creationDate;
    }
    public void setCreationDate(Date creationDate) {
        this.creationDate = creationDate;
    }
    
    @Column(name="MODIFED_DATE")
    public Date getModifedDate() {
        return modifedDate;
    }
    public void setModifedDate(Date modifedDate) {
        this.modifedDate = modifedDate;
    }
    
    @Column(name="CONTENT")
    public String getContent() {
        return content;
    }
    public void setContent(String content) {
        this.content = content;
    }
}
 

Creating a new instance and using UUID :

Code:

package com.codemiles.jpa;

import java.util.Date;
import java.util.UUID;
import javax.persistence.EntityManager;

public abstract class Loader {
    protected abstract EntityManager getEntityManager();
    /**
     * @param args
     */
    public static void main(String[] args) {
    Topic topic = new Topic();
    topic.setId(UUID.randomUUID().toString());
    topic.setContent("Topic At Codemiles");
    topic.setCreationDate(new Date(System.currentTimeMillis()));
    topic.setModifedDate(new Date(System.currentTimeMillis()));
    topic.setTitle("UUID topic ");
     /*
        persistence code .
         getEntityManager().persist(topic);
      
      */
    }

}
 

UUID as key

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