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hibernate jpa基本映射

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作者 正文
   发表时间:2012-03-20  

 

了解常用注解:

       @Entity

       @Id

       @Table

       @GeneratedValue

       @Transient

       @Column

      

采用如下注解会默认采用数据库的主键生成能力,相当于hibernate中的native

@GeneratedValue相当于@GeneratedValue(strategy=GenerationType.AUTO)

 

了解如何采用hibernateuuid生成主键 

 

package com.hjc.hibernate;
import javax.persistence.Column;
import javax.persistence.Entity;
import javax.persistence.GeneratedValue;
import javax.persistence.Id;
import javax.persistence.Table;
import javax.persistence.Transient;
@Entity
@Table(name="t_user1")
public class User1 {
	private int id;	
	private String name;	
	private int age;		
	@Id
	//采用数据库自增方式生成主键
	//@GeneratedValue(strategy=GenerationType.AUTO)
	@GeneratedValue
	public int getId() {
		return id;
	}
	public void setId(int id) {
		this.id = id;
	}	
	@Column(name="user_name", length=30, nullable=false, unique=true)
	public String getName() {
		return name;
	}
	public void setName(String name) {
		this.name = name;
	}
	//年龄不持久化
	@Transient
	public int getAge() {
		return age;
	}
	public void setAge(int age) {
		this.age = age;
	}
}
 
package com.hjc.hibernate;
import javax.persistence.Entity;
import javax.persistence.GeneratedValue;
import javax.persistence.GenerationType;
import javax.persistence.Id;
import javax.persistence.Table;
@Entity
@Table(name="t_user2")
public class User2 {
	private int id;	
	private String name;	
	public String getName() {
		return name;
	}
	public void setName(String name) {
		this.name = name;
	}	
	@Id
	@GeneratedValue(strategy=GenerationType.IDENTITY)
	public int getId() {
		return id;
	}
	public void setId(int id) {
		this.id = id;
	}
}
 

package com.hjc.hibernate;
import javax.persistence.Entity;
import javax.persistence.GeneratedValue;
import javax.persistence.GenerationType;
import javax.persistence.Id;
import javax.persistence.Table;

@Entity
@Table(name="t_user3")
public class User3 {
	private int id;	
	private String name;	
	public String getName() {
		return name;
	}
	public void setName(String name) {
		this.name = name;
	}	
	@Id
	@GeneratedValue(strategy=GenerationType.TABLE)
	public int getId() {
		return id;
	}
	public void setId(int id) {
		this.id = id;
	}
}
 
package com.hjc.hibernate;
import javax.persistence.Entity;
import javax.persistence.GeneratedValue;
import javax.persistence.Id;
import javax.persistence.Table;
import org.hibernate.annotations.GenericGenerator;
@Entity
@Table(name="t_user4")
public class User4 {
	private String id;	
	private String name;
	public String getName() {
		return name;
	}
	public void setName(String name) {
		this.name = name;
	}	
	//采用hibernate uuid生成器
	@Id
	@GenericGenerator(name="myIdGenerator",strategy="uuid")
	@GeneratedValue(generator="myIdGenerator")
	public String getId() {
		return id;
	}
	public void setId(String id) {
		this.id = id;
	}
}

 

public void testSave1() {
		Session session = null;
		try {
			session = HibernateUtils.getSession();
			session.beginTransaction();
			
			User1 user = new User1();
			user.setName("李四11");
			
			session.save(user);
			
			session.getTransaction().commit();
		}catch(Exception e) {
			e.printStackTrace();
			session.getTransaction().rollback();
		}finally {
			HibernateUtils.closeSession(session);
		}
	}
	
	public void testSave2() {
		Session session = null;
		try {
			session = HibernateUtils.getSession();
			session.beginTransaction();
			
			User2 user = new User2();
			user.setName("李四");
		
			session.save(user);
			
			session.getTransaction().commit();
		}catch(Exception e) {
			e.printStackTrace();
			session.getTransaction().rollback();
		}finally {
			HibernateUtils.closeSession(session);
		}
	}	
	
	public void testSave3() {
		Session session = null;
		try {
			session = HibernateUtils.getSession();
			session.beginTransaction();
			
			User3 user = new User3();
			user.setName("张三");
		
			session.save(user);
			
			session.getTransaction().commit();
		}catch(Exception e) {
			e.printStackTrace();
			session.getTransaction().rollback();
		}finally {
			HibernateUtils.closeSession(session);
		}
	}	
	
	public void testSave4() {
		Session session = null;
		try {
			session = HibernateUtils.getSession();
			session.beginTransaction();
			
			User4 user = new User4();
			user.setName("张三");
		
			session.save(user);
			
			session.getTransaction().commit();
		}catch(Exception e) {
			e.printStackTrace();
			session.getTransaction().rollback();
		}finally {
			HibernateUtils.closeSession(session);
		}
	}		
 
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