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Hibernate實現(xiàn)CRUD操作

最近學(xué)習(xí)hibernate有幾天了，基本學(xué)會簡單的增刪改查，現(xiàn)在就把實現(xiàn)分享如下：

一：首先需要建立數(shù)據(jù)庫，而我采用的mysql數(shù)據(jù)庫,為了更詳細(xì)hibernate的映射，我把數(shù)據(jù)庫表名和字段名與實體類的類名與屬性名取得不一致。

create table t_teacher(

id int auto_increment,

t_username varchar(50),

t_age int,

primary key(id)

);

二：建立數(shù)據(jù)源連接：hibernate.cfg.xml

<?xml version='1.0' encoding='utf-8'?>

<!DOCTYPE hibernate-configuration PUBLIC

"-//Hibernate/Hibernate Configuration DTD 3.0//EN"

"http://www.hibernate.org/dtd/hibernate-configuration-3.0.dtd">

<hibernate-configuration>

<session-factory>

<property name="connection.driver_class">com.mysql.jdbc.Driver</property>

<property name="connection.url">jdbc:mysql://localhost:3306/hxj</property>

<property name="dialect">org.hibernate.dialect.MySQLDialect</property>

<property name="current_session_context_class">thread</property>

<property name="cache.provider_class">org.hibernate.cache.NoCacheProvider</property>

<property name="hbm2ddl.auto">update</property>

</session-factory>

</hibernate-configuration>

三：建立實體類：Teacher，由于我采用注解方式進行配置，所以需要再實體類上面加上注解。

package com.wsw.hibernate.model;

import java.io.Serializable;

import javax.persistence.Column;

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_teacher")

public class Teacher implements Serializable {

private int id;

private String username;

private int age;

@Id

@GenericGenerator(name = "generator", strategy = "increment")

@GeneratedValue(generator = "generator")

@Column(name = "id")

public int getId() {

return id;

}

public void setId(int id) {

this.id = id;

}

@Column(name="t_username")

public String getUsername() {

return username;

}

public void setUsername(String username) {

this.username = username;

}

@Column(name="t_age")

public int getAge() {

return age;

}

public void setAge(int age) {

this.age = age;

}

四：創(chuàng)建獲取SessionFactory的單例類：

package com.wsw.hibernate.util;

import org.hibernate.SessionFactory;

import org.hibernate.cfg.AnnotationConfiguration;

import org.hibernate.cfg.Configuration;

public class HibernateUtil {

private static final SessionFactory sessionFactory;

static {

try {

// Create the SessionFactory from hibernate.cfg.xml

//sessionFactory = new Configuration().configure().buildSessionFactory();

sessionFactory = new AnnotationConfiguration().configure()

.buildSessionFactory();

} catch (Throwable ex) {

// Make sure you log the exception, as it might be swallowed

System.err.println("Initial SessionFactory creation failed." + ex);

throw new ExceptionInInitializerError(ex);

}

public static SessionFactory getSessionFactory() {

return sessionFactory;

}

五：實現(xiàn)hibernate的CURD操作：

package com.wsw.hibernate.action;

import java.util.List;

import org.hibernate.Query;

import org.hibernate.Session;

import org.hibernate.Transaction;

import com.wsw.hibernate.model.Person;

import com.wsw.hibernate.model.Teacher;

import com.wsw.hibernate.util.HibernateUtil;

public class TeacherManager {

public static void main(String[] args) {

//selectTeacher_By_Load(1);

insertTeacher();

//deleteTeacher();

selectAll();

//updateTeacher();

//insertTeacher();

//createAndStoreTeacher();

//select_All_By_Get(2);

//select_AllPerson_By_Get();

//annotation();

//HibernateUtil.getSessionFactory().close();

}

/**

* 插入記錄

*/

private static void insertTeacher() {

Session session = HibernateUtil.getSessionFactory().getCurrentSession();

session.beginTransaction();

Teacher teacher = new Teacher();

teacher.setUsername("aaa");

teacher.setAge(25);

session.save(teacher);

session.getTransaction().commit();

System.out.println("insert teacher successfully");

}

/**

* 刪除記錄操作

*/

private static void deleteTeacher() {

int count;

Session session = HibernateUtil.getSessionFactory().getCurrentSession();

session.beginTransaction();

Query query = session.createQuery("delete Teacher where id=?");

query.setParameter(0, 1);

count = query.executeUpdate(); // 刪除記錄采用Update方式

session.getTransaction().commit();

System.out.println("刪除" + count + "條teacher記錄");

}

/**

* 根據(jù)id采用load方式查詢

* @param id

*/

private static void selectTeacher_By_Load(int id) {

Session session = HibernateUtil.getSessionFactory().openSession();

// load獲取值不能采用這種方式獲取session對象，因為load采用延遲加載/懶加載。而getCurrentSession()獲取session時會自動關(guān)閉session對象，

// 所以會導(dǎo)致對象沒有保存到內(nèi)存中，然后你使用該對象了，導(dǎo)致該：org.hibernate.LazyInitializationException異常。

//Session session = HibernateUtil.getSessionFactory().getCurrentSession();

session.beginTransaction();

Teacher teacher = (Teacher)session.load(Teacher.class, id); // 只能是主鍵id獲取對象值，不能以其他的表字段名獲取對象值，否則，只能用HQL語句查詢。

System.out.println("load方式commit之前====>Id:" + teacher.getId() + " UserName:" + teacher.getUsername() + " Age:" + teacher.getAge());

session.getTransaction().commit();

System.out.println("load方式commit之后====》Id:" + teacher.getId() + " UserName:" + teacher.getUsername() + " Age:" + teacher.getAge());

session.close(); // load獲取值session方式需要手動關(guān)閉session對象，而通過getCurrentSession()則會自動關(guān)閉session對象

}

/**

* 根據(jù)id采用get方式查詢

* @param id

*/

private static void selectTeacher_By_Get(int id) {

Session session = HibernateUtil.getSessionFactory().getCurrentSession();

session.beginTransaction();

Teacher teacher = (Teacher)session.get(Teacher.class, id);

System.out.println("get方式commit之前====>Id:" + teacher.getId() + " UserName:" + teacher.getUsername() + " Age:" + teacher.getAge());

session.getTransaction().commit();

System.out.println("get方式commit之后====>Id:" + teacher.getId() + " UserName:" + teacher.getUsername() + " Age:" + teacher.getAge());

}

/**

* 按條件查詢記錄

*/

private static void selectAll_By_Request() {

Session session = HibernateUtil.getSessionFactory().getCurrentSession();

session.beginTransaction();

Query query = session.createQuery("from Teacher where id=? and age=:tage"); //在條件語句中，可以用？和:兩種方式。兩者方式各有不同。

query.setParameter(0, 2); // 從0開始，而不是從1開始。采用？方式。

//query.setInteger(0, 2); // 上面的query.setParameter(0, 2)也可以用query.setInteger(0, 2)代替，效果一樣

query.setParameter("tage", 27); // 采用：方式。前面參數(shù)名與之前的：后面的參數(shù)名必須一致。

//query.setInteger("tage", 27); // 上面的query.setParameter("tage", 27)也可以用query.setInteger("tage", 27)代替，效果一樣

List<Teacher> listteacher = (List<Teacher>)query.list();

printList(listteacher);

}

/**

* 查詢?nèi)坑涗?br />

*/

private static void selectAll() {

Session session = HibernateUtil.getSessionFactory().getCurrentSession();

session.beginTransaction();

Query query = session.createQuery("from Teacher");

List<Teacher> listteacher = (List<Teacher>)query.list();

printList(listteacher);

}

/**

* 更新操作

*/

private static void updateTeacher() {

int count;

Session session = HibernateUtil.getSessionFactory().getCurrentSession();

session.beginTransaction();

Query query= session.createQuery("update Teacher set t_username='何小景' where id=?");

query.setInteger(0, 2);

count = query.executeUpdate();

session.getTransaction().commit();

System.out.println("更新" + count +"條記錄");

}

/**

* 打印List<Person>對象集合

* @param listteacher

*/

private static void printList(List<Teacher> listteacher){

for(Teacher teacher : listteacher) {

System.out.println("Id:" + teacher.getId() + " UserName:" + teacher.getUsername() + " Age:" + teacher.getAge());

}

posted on 2012-06-30 10:29 奮斗成就男人閱讀(2950) 評論(0) 編輯收藏

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Hibernate實現(xiàn)CRUD操作