hibernate入门

1. 什么是hibernate

ORM框架/持久层框架 jdbc的一个框架
object reference mapping
通过管理对象来改变数据库中的数据
通过管理对象来操作数据库
mybatis
优势：跨数据库的无缝移植

2. 如何在项目中添加hibernate支持(手动添加)

2.1 添加hibernate相关依赖

<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/maven-v4_0_0.xsd">
  <modelVersion>4.0.0</modelVersion>
  <groupId>com.zh</groupId>
  <artifactId>hibernate</artifactId>
  <packaging>war</packaging>
  <version>0.0.1-SNAPSHOT</version>
  <name>hibernate Maven Webapp</name>
  <url>http://maven.apache.org</url>
  
  <properties>
		<project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
		<maven.compiler.source>1.8</maven.compiler.source>
		<maven.compiler.target>1.8</maven.compiler.target>
		<junit.version>4.12</junit.version>
		<servlet.version>4.0.0</servlet.version>
		<hibernate.version>5.3.0.Final</hibernate.version>
		<mysql.driver.version>5.1.46</mysql.driver.version>
	</properties>
  
  <dependencies>
    <dependency>
		<groupId>junit</groupId>
		<artifactId>junit</artifactId>
		<version>${junit.version}</version>
		<scope>test</scope>
	</dependency>
	
	<dependency>
		<groupId>javax.servlet</groupId>
		<artifactId>javax.servlet-api</artifactId>
		<version>${servlet.version}</version>
		<scope>provided</scope>
	</dependency>
	
	<dependency>
		<groupId>org.hibernate</groupId>
		<artifactId>hibernate-core</artifactId>
		<version>${hibernate.version}</version>
	</dependency>
	
	<dependency>
		<groupId>mysql</groupId>
		<artifactId>mysql-connector-java</artifactId>
		<version>${mysql.driver.version}</version>
	</dependency>	
		
	
  </dependencies>
  <build>
    <finalName>hibernate</finalName>
    <plugins>
		<plugin>
			<groupId>org.apache.maven.plugins</groupId>
			<artifactId>maven-compiler-plugin</artifactId>
			<version>3.7.0</version>
			<configuration>
				<source>${maven.compiler.source}</source>
				<target>${maven.compiler.target}</target>
				<encoding>${project.build.sourceEncoding}</encoding>
			</configuration>
		</plugin>
	</plugins>
  </build>
</project>

2.2 在resource目录下添加hibernate.cfg.xml(核心配置文件)

2.2.1 添加DTD支持

2.2.2 添加Hibernate的配置

2.2.2.1 数据库相关(connection.username|connection.password|connection.url|connection.driver_class|dialect)
2.2.2.2 调试相关(show_sql|format_sql)

<?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>
		<!-- 1. 数据库相关 -->
		<property name="connection.username">mybatis_ssm</property>
		<property name="connection.password">xiaoli</property>
		<property name="connection.url">jdbc:mysql://localhost:3306/mybatis_ssm?useUnicode=true&amp;characterEncoding=UTF-8
		</property>
		<property name="connection.driver_class">com.mysql.jdbc.Driver</property>
		<property name="dialect">org.hibernate.dialect.MySQLDialect</property>

		<!-- 配置本地事务（No CurrentSessionContext configured!） -->
		<property name="hibernate.current_session_context_class">thread</property>

		<!-- 2. 调试相关 -->
		<property name="show_sql">true</property>
		<property name="format_sql">true</property>

	</session-factory> 
</hibernate-configuration>

2.3 在开发阶段再创建实体类和实体映射文件(*.hbm.xml)

  实体必须实现Serializable接口

public class User implements Serializable{
	/**
	 * 
	 */
	private static final long serialVersionUID = 1L;
	private Integer id;
	private String userName;
	private String userPwd;
	private String sex;
	private Date birthday;
	private String realName;
	private Timestamp createDatetime;
	private String remark;
	public Integer getId() {
		return id;
	}
	public void setId(Integer id) {
		this.id = id;
	}
	public String getUserName() {
		return userName;
	}
	public void setUserName(String userName) {
		this.userName = userName;
	}
	public String getUserPwd() {
		return userPwd;
	}
	public void setUserPwd(String userPwd) {
		this.userPwd = userPwd;
	}
	public String getSex() {
		return sex;
	}
	public void setSex(String sex) {
		this.sex = sex;
	}
	public Date getBirthday() {
		return birthday;
	}
	public void setBirthday(Date birthday) {
		this.birthday = birthday;
	}
	public String getRealName() {
		return realName;
	}
	public void setRealName(String realName) {
		this.realName = realName;
	}
	public Timestamp getCreateDatetime() {
		return createDatetime;
	}
	public void setCreateDatetime(Timestamp createDatetime) {
		this.createDatetime = createDatetime;
	}
	public String getRemark() {
		return remark;
	}
	public void setRemark(String remark) {
		this.remark = remark;
	}
	public User() {
		super();
	}
	public User(Integer id, String userName, String userPwd, String sex, Date birthday, String realName,
			Timestamp createDatetime, String remark) {
		super();
		this.id = id;
		this.userName = userName;
		this.userPwd = userPwd;
		this.sex = sex;
		this.birthday = birthday;
		this.realName = realName;
		this.createDatetime = createDatetime;
		this.remark = remark;
	}
	@Override
	public String toString() {
		return "User [id=" + id + ", userName=" + userName + ", userPwd=" + userPwd + ", sex=" + sex + ", birthday="
				+ birthday + ", realName=" + realName + ", createDatetime=" + createDatetime + ", remark=" + remark
				+ "]";
	}
	
}

User.hbm.xml

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE hibernate-mapping PUBLIC 
    "-//Hibernate/Hibernate Mapping DTD 3.0//EN"
    "http://www.hibernate.org/dtd/hibernate-mapping-3.0.dtd">
<hibernate-configuration>
<!-- 
	class标签:
		name:对应的是需要映射的实体类的全路径名
		table:实体类对应的数据库中的表
		
	id标签: 配置的是表中的主键
		name:对应的是实体类属性名
		type:指的是实体类数据类型
		column:数据库对应的列段
		
	property标签:配置除主键以外的列段对应的类属性映射关系
		name:对应的是实体类属性名
		type:指的是实体类数据类型
		column:数据库对应的列段
		insert="false" update="false"表示该列段或者说该属性只做查询,不做更新	
		
 -->
	<class name="com.one.entity.User" table="t_hibernate_user">
		<id name="id" type="java.lang.Integer" column="id">
			<generator class="increment" />
		</id>
		<property name="userName" type="java.lang.String" column="user_name">
		</property>
		<property name="userPwd" type="java.lang.String" column="user_pwd">
		</property>
		<property name="realName" type="java.lang.String" column="real_name">
		</property>
		<property name="sex" type="java.lang.String" column="sex">
		</property>
		<property name="birthday" type="java.sql.Date" column="birthday">
		</property>
		<property insert="false" update="false" name="createDatetime"
			type="java.sql.Timestamp" column="create_datetime">
		</property>
		<property name="remark" type="java.lang.String" column="remark">
		</property>
	</class>

</hibernate-configuration>

小结：hibernate.cfg.xml(1)/*.hbm.xml(N)
实体映射文件一定要加到核心配置文件

Demo

查询QueryDemo

package com.one.demo;

import org.hibernate.cfg.Configuration;
/**
 * hibernate查询
 * @author Dragon
 *
 */
public class QueryDemo {
	public static void main(String[] args) {
		Configuration configure = new Configuration().configure("/hibernate.cfg.xml");
		SessionFactory sessionFactory = configure.buildSessionFactory();
//		会话,这里的会话指的是操作数据库的连接		
		Session session = sessionFactory.openSession();
		List list = session.createQuery("from User").list();
		for (Object obj : list) {
			System.out.println(obj);
		}
		session.close();
	}
}

InsertDemo

public class InsertDemo {
	
	public static void main(String[] args) {
		Configuration configure = new Configuration().configure("/hibernate.cfg.xml");
		SessionFactory sessionFactory = configure.buildSessionFactory();
		Session session = sessionFactory.openSession();
		Transaction transaction = session.beginTransaction();
		session.save(new User("狗子", "222", 1));
		transaction.commit();
		session.close();
	}
}

UpdateDemo

public static void main(String[] args) {
			Configuration configure = new Configuration().configure("/hibernate.cfg.xml");
			SessionFactory sessionFactory = configure.buildSessionFactory();
			
			Session session = sessionFactory.openSession();
			Transaction transaction = session.beginTransaction();
			
			User user = session.get(User.class,4);
			user.setUser_name("红太狼");
			System.out.println(user);
			
			transaction.commit();
			session.close();
		}

DeleteDemo

public static void main(String[] args) {
		Configuration configure = new Configuration().configure("/hibernate.cfg.xml");
		SessionFactory sessionFactory = configure.buildSessionFactory();
		
		Session session = sessionFactory.openSession();
		Transaction transaction = session.beginTransaction();
		
		User user=new User();
		user.setUser_id(4);
		session.delete(user);
		transaction.commit();
		session.close();
	}

hibernate管理对象的三种状态