第一個Hibernate示例，使用Maven來管理jar包
阿新 • • 發佈：2018-12-09
注意：不同版本好像會有點不一樣，特別是在後續跟spring整合時要注意版本問題。這裡用的是Hibernate 3 版本的。。。
1.SQL指令碼
//SQL指令碼
CREATE TABLE USER (
USER_ID INT PRIMARY KEY AUTO_INCREMENT
NAME VARCHAR(20),
PASSWORD VARCHAR(12),
TYPE VARCHAR(6)
)2. pom.xml
<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd"> <modelVersion>4.0.0</modelVersion> <groupId>com.lin</groupId> <artifactId>HibernateFirstDemo</artifactId> <version>0.0.1-SNAPSHOT</version> <packaging>war</packaging> <dependencies> <!-- Hibernate --> <dependency> <groupId>org.hibernate</groupId> <artifactId>hibernate-core</artifactId> <version>3.6.10.Final</version> </dependency> <dependency> <groupId>org.hibernate</groupId> <artifactId>hibernate-entitymanager</artifactId> <version>3.6.10.Final</version> </dependency> <!-- MySQL驅動包 --> <dependency> <groupId>mysql</groupId> <artifactId>mysql-connector-java</artifactId> <version>5.1.41</version> </dependency> <!-- slf4j --> <dependency> <groupId>org.slf4j</groupId> <artifactId>slf4j-nop</artifactId> <version>1.7.25</version> <scope>test</scope> </dependency> <!-- jstl、servlet-api、junit --> <dependency> <groupId>javax.servlet</groupId> <artifactId>jstl</artifactId> <version>1.2</version> </dependency> <dependency> <groupId>javax.servlet</groupId> <artifactId>javax.servlet-api</artifactId> <version>4.0.1</version> <scope>provided</scope> </dependency> <dependency> <groupId>junit</groupId> <artifactId>junit-dep</artifactId> <version>4.10</version> <scope>test</scope> </dependency> </dependencies> </project>
3.實體類User.java
package com.lin.pojo; import java.io.Serializable; public class User implements Serializable{ private static final long serialVersionUID = 1L; private int id; private String name; private String password; private String type; @Override public String toString() { return "User [id=" + id + ", name=" + name + ", password=" + password + ", type=" + type + "]"; } public int getId() { return id; } public void setId(int id) { this.id = id; } public String getName() { return name; } public void setName(String name) { this.name = name; } public String getPassword() { return password; } public void setPassword(String password) { this.password = password; } public String getType() { return type; } public void setType(String type) { this.type = type; } public User(int id, String name, String password, String type) { super(); this.id = id; this.name = name; this.password = password; this.type = type; } public User() { super(); } }
4.表跟實體類的對映User.hbm.xml
<?xml version="1.0" encoding="UTF-8"?> <!DOCTYPE hibernate-mapping PUBLIC "-//Hibernate/Hibernate Mapping DTD 3.0//EN" "http://hibernate.sourceforge.net/hibernate-mapping-3.0.dtd"> <!-- 1.通過對映檔案可以告訴Hibernate，User類被持久化為資料庫中的User表。 2.根據對映檔案，Hibernate可以生成足夠的資訊以產生所有的SQL語句，即User類的例項進行增刪改查所需的SQL語句。 --> <hibernate-mapping> <!-- name指定持久化類的類名，table指定資料表的表名 --> <class name="com.lin.pojo.User" table="USER"> <!-- 將User類中的id對映為資料表USER中的主鍵USER_ID --> <id name="id" type="java.lang.Integer" column="user_id"> <!-- 指定主鍵的生成方式 --> <generator class="increment"/> </id> <!-- 對映User類的其他普通屬性 --> <property name="name" type="java.lang.String" column="name" length="20"></property> <property name="password" type="java.lang.String" column="password" length="12"></property> <property name="type" type="java.lang.String" column="type" length="6"></property> </class> </hibernate-mapping>
5.Hibernate配置檔案hibernate.cfg.xml
<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE hibernate-configuration PUBLIC
"-//Hibernate/Hibernate Configuration DTD 3.0//EN"
"http://hibernate.sourceforge.net/hibernate-configuration-3.0.dtd">
<!--
Hibernate配置檔案主要用來配置資料庫連線以及Hibernate執行時所需的各個屬性的值
-->
<hibernate-configuration>
<session-factory>
<!-- 資料庫連線設定 -->
<!-- 配置資料庫JDBC驅動 -->
<property name="hibernate.connection.driver_class">com.mysql.jdbc.Driver</property>
<!-- 配置資料庫連線URL -->
<property name="hibernate.connection.url">jdbc:mysql://localhost:3306/hibernate</property>
<!-- 配置資料庫使用者名稱 -->
<property name="hibernate.connection.username">root</property>
<!-- 配置資料庫密碼 -->
<property name="hibernate.connection.password">546784</property>
<!-- 配置JDBC內建連線池 -->
<property name="connection.pool_size">1</property>
<!-- 配置資料庫方言 -->
<property name="dialect">org.hibernate.dialect.MySQLDialect</property>
<!-- 輸出執行時生成的SQL語句 -->
<property name="show_sql">true</property>
<!-- 列出所有的對映檔案 -->
<mapping resource="hibernate/mappings/User.hbm.xml" />
</session-factory>
</hibernate-configuration>6.Hibernate的輔助工具類HibernateUtil.java
package com.lin.utils;
import org.hibernate.HibernateException;
import org.hibernate.Session;
import org.hibernate.SessionFactory;
import org.hibernate.cfg.Configuration;
public class HibernateUtil {
private static SessionFactory sessionFactory;
private static Configuration configuration;
//建立執行緒區域性變數threadLocal，用來儲存Hibernate的Session
private static final ThreadLocal<Session> threadLocal = new ThreadLocal<Session>();
//使用靜態程式碼塊初始化Hibernate
static{
try{
//如果不指定hibernate的配置檔案位置，那麼它會預設到classpath路徑下查詢名為hibernate.cfg.xml的檔案
Configuration cfg = new Configuration().configure("/hibernate/hibernate.cfg.xml");
//建立SessionFactory
sessionFactory = cfg.buildSessionFactory();
}catch(Throwable ex){
throw new ExceptionInInitializerError(ex);
}
}
//獲得SessionFactory
public static SessionFactory getSessionFactory(){
return sessionFactory;
}
//獲得ThreadLocal物件管理的Session例項
public static Session getSession() throws HibernateException {
Session session = (Session)threadLocal.get();
if(session == null || session.isOpen()){
if(sessionFactory == null){
rebuildSessionFactory();
}
//通過SessionFactory物件建立Session物件
session = (sessionFactory != null)?sessionFactory.openSession():null;
//將新開啟的Session例項儲存到執行緒區域性變數threadLocal中
threadLocal.set(session);
}
return session;
}
//關閉Session例項
public static void closeSession() throws HibernateException {
//從執行緒區域性變數threadLocal中獲取之前存入的Session例項
Session session = (Session)threadLocal.get();
threadLocal.set(null);
if(session != null){
session.close();
}
}
//重建SessionFactory
public static void rebuildSessionFactory() {
try{
configuration.configure("/hibernate/hibernate.cfg.xml");
sessionFactory = configuration.buildSessionFactory();
}catch(Exception e){
System.out.println("Error Creating SessionFactory ");
e.printStackTrace();
}
}
//關閉快取和連線池
public static void shutdown(){
getSessionFactory().close();
}
}
7.Dao介面UserDao.java
package com.lin.dao;
import com.lin.pojo.User;
public interface UserDao {
void save(User user);
User findById(int id);
void delete(User user);
void update(User user);
}
8.Dao介面實現類UserDaoImpl.java
package com.lin.dao.impl;
import org.hibernate.Session;
import org.hibernate.Transaction;
import com.lin.dao.UserDao;
import com.lin.pojo.User;
import com.lin.utils.HibernateUtil;
public class UserDaoImpl implements UserDao {
// 新增使用者
public void save(User user) {
// 生成Session例項
Session session = HibernateUtil.getSession();
// 建立Transaction例項
Transaction tx = session.beginTransaction();
try {
session.save(user);
tx.commit();// 提交事務
} catch (Exception e) {
e.printStackTrace();
tx.rollback();// 回滾事務
} finally {
HibernateUtil.closeSession();
}
}
// 按id查詢使用者
public User findById(int id) {
User user = null;
// 生成Session例項
Session session = HibernateUtil.getSession();
// 建立Transaction例項
Transaction tx = session.beginTransaction();
try {
// 使用Session的get方法獲取指定id的使用者到記憶體中
user = (User) session.get(User.class, id);
tx.commit();// 提交事務
} catch (Exception e) {
e.printStackTrace();
tx.rollback();// 回滾事務
} finally {
HibernateUtil.closeSession();
}
return user;
}
public void delete(User user) {
// 生成Session例項
Session session = HibernateUtil.getSession();
// 建立Transaction例項
Transaction tx = session.beginTransaction();
try {
// 使用Session的delete方法將持久化物件刪除
session.delete(user);
tx.commit();// 提交事務
} catch (Exception e) {
e.printStackTrace();
tx.rollback();// 回滾事務
} finally {
HibernateUtil.closeSession();
}
}
public void update(User user) {
// 生成Session例項
Session session = HibernateUtil.getSession();
// 建立Transaction例項
Transaction tx = session.beginTransaction();
try {
// 使用Session的update方法更新持久化物件
session.update(user);
tx.commit();// 提交事務
} catch (Exception e) {
e.printStackTrace();
tx.rollback();// 回滾事務
} finally {
HibernateUtil.closeSession();
}
}
}
9.測試類UserTest.java（增刪改查操作）
package com.lin.test;
import org.junit.Test;
import com.lin.dao.UserDao;
import com.lin.dao.impl.UserDaoImpl;
import com.lin.pojo.User;
public class UserTest {
//新增
@Test
public void testSave(){
UserDao userDao = new UserDaoImpl();
try{
User u = new User();
u.setId(10);
u.setName("linlin123");
u.setPassword("123");
u.setType("user");
userDao.save(u);
}catch(Exception e){
e.printStackTrace();
}
}
//刪除
@Test
public void testDelete(){
UserDao userDao = new UserDaoImpl();
//根據id查詢使用者
User u = userDao.findById(3);
System.out.println(u);
//刪除
userDao.delete(u);
System.out.println("成功刪除了id為"+u.getId()+"的使用者！");
}
//修改
@Test
public void testUpdate(){
UserDao userDao = new UserDaoImpl();
//根據id查詢使用者
User u = userDao.findById(2);
System.out.println(u);
u.setName("楊");
u.setType("admin");
System.out.println(u);
//修改
userDao.update(u);
System.out.println("成功修改了id為"+u.getId()+"的使用者資訊！");
}
}