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

优势:跨数据库的无缝移植

注1:Object Relational Mapping
1、加载驱动
2、建立连接
3、获取预定义处理对象 preparestatment
4、执行sql
5、处理结果集
6、关闭

  1. 如何在项目中添加hibernate支持(手动添加)
    2.1 添加hibernate相关依赖
    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
    2.2.2.2 调试相关(show_sql|format_sql)
(connection.username|connection.password|connection.url|connection.driver_class|dialect)

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

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

  1. hibernate核心API讲解
    3.1 Configuration
    读取hibernate.cfg.xml
    3.2 SessionFactory(1)
    3.3 Session(N)
    注1:
    注2:
    3.3.1 save
    3.3.2 get
    load
    3.3.3 delete(先查再删除,保证程序的健壮性)
    User u = (User) session.get(User.class,99);
    if(null!=u){
    session.delete(u);//比如id=99不存在,直接删除就会报错
    }
    3.3.4 update
    先查再改

    局部修改

    3.3.4 createQuery

3.4 Transaction(自动事务和手动事务讲解)
commit/rollback

3.5 Query(hql一章讲)
查全部/批量修改或删除
list setXxx(String name,Xxx value); setParameter(String name, Object value) setParameterList(String name, Collection values) setParameterList(String name, Object[] values) setFirstResult/setMaxResults

  1. 如何使用hibernate完成CRUD操作
    4.1 CRUD操作步骤
    4.1.1 读取配置
    4.1.2 创建SessionFactory
    4.1.3 打开Session
    4.1.4 开启事务
    4.1.5 CURD
    4.1.6 提交事务/回滚事务
    4.1.7 关闭Session
    4.2 注意事项
    4.2.1 hibernate默认使用的是手动事务,因此必须显示的开启和提交事务
    4.2.2 删除操作时,必须先查再删

  2. 工具类SessionFactoryUtil

  3. OID属性
    与数据库主键列映射的属性


hibernate/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/maven-v4_0_0.xsd">
   <modelVersion>4.0.0</modelVersion>
   <groupId>com.lrc</groupId>
   <artifactId>hibernate</artifactId>
   <packaging>war</packaging>
   <version>0.0.1-SNAPSHOT</version>
   <name>lrc_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>

User


package com.lrc.a.entity;

import java.sql.Date;
import java.sql.Timestamp;

public class User {
	private Integer id;
	private String userName;
	private String userPwd;
	private String realName;
	private String sex;
	private Date birthday;
	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 getRealName() {
		return realName;
	}

	public void setRealName(String realName) {
		this.realName = realName;
	}

	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 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;
	}

	@Override
	public String toString() {
		return "User [id=" + id + ", userName=" + userName + ", userPwd=" + userPwd + ", realName=" + realName
				+ ", sex=" + sex + ", birthday=" + birthday + ", createDatetime=" + createDatetime + ", remark="
				+ remark + "]";
	}

	public User(String userName, String userPwd, String realName, String sex, Date birthday, Timestamp createDatetime,
			String remark) {
		super();
		this.userName = userName;
		this.userPwd = userPwd;
		this.realName = realName;
		this.sex = sex;
		this.birthday = birthday;
		this.createDatetime = createDatetime;
		this.remark = remark;
	}

	public User() {
		super();
	}

}

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>
		<!-- 1. 数据库相关 -->
		<property name="connection.username">root</property>
		<property name="connection.password">123</property>
		<property name="connection.url">jdbc:mysql://127.0.0.1:3306/sys?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>

		<!-- 3. 添加实体映射文件 -->
		<mapping resource="com/lrc/a/entity/User.hbm.xml" />
	</session-factory>
</hibernate-configuration>


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-mapping>
	<!-- 
		class标签下的属性
			name:指的是数据库中的表所映射的类的全路径名
			table:要映射的数据库表
		
		id标签:是用来表示主键的映射列
			name:数据库表的列段映射到实体类中的属性名
			type:属性名的类型
			column:数据库中的列段
			
		property标签:
			name:数据库表的列段映射到实体类中的属性名
			type:属性名的类型
			column:数据库中的列段
	 -->
	<class name="com.lrc.a.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-mapping>

AddDemo


package com.lrc.a.test;

import java.sql.Date;
import java.sql.Timestamp;
import java.util.List;

import org.hibernate.Session;
import org.hibernate.SessionFactory;
import org.hibernate.Transaction;
import org.hibernate.cfg.Configuration;

import com.lrc.a.entity.User;

/**
 * 演示hibernate新增
 * 
 * @author Administrator
 *
 */
public class AddDemo {
	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("zs", "123", "张三", "人妖", new Date(System.currentTimeMillis()), new Timestamp(System.currentTimeMillis()), "玩玩而已,不必当真");
		session.save(user);
		
		transaction.commit();
		session.close();
	}
}

DelDemo


package com.lrc.a.test;

import java.sql.Date;
import java.sql.Timestamp;
import java.util.List;

import org.hibernate.Session;
import org.hibernate.SessionFactory;
import org.hibernate.Transaction;
import org.hibernate.cfg.Configuration;

import com.lrc.a.entity.User;

/**
 * 演示hibernate删除
 * 
 * @author Administrator
 *
 */
public class DelDemo {
	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.setId(15);
		session.delete(user);
		
		transaction.commit();
		session.close();
	}
}

EditDemo


package com.lrc.a.test;

import java.sql.Date;
import java.sql.Timestamp;
import java.util.List;

import org.hibernate.Session;
import org.hibernate.SessionFactory;
import org.hibernate.Transaction;
import org.hibernate.cfg.Configuration;

import com.lrc.a.entity.User;

/**
 * 演示hibernate修改
 * 
 * @author Administrator
 *
 */
public class EditDemo {
	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("ww", "12345", "王五", "人妖", new Date(System.currentTimeMillis()), new Timestamp(System.currentTimeMillis()), "换一个玩玩");
//		user.setId(15);
//		session.update(user);
		User user = session.get(User.class, 15);
		user.setRealName("吴亦凡");
		System.out.println(user);
		
		transaction.commit();
		session.close();
	}
}

QueryDemo


package com.lrc.a.test;

import java.util.List;

import org.hibernate.Session;
import org.hibernate.SessionFactory;
import org.hibernate.cfg.Configuration;

/**
 * 演示hibernate查询
 * 
 * @author Administrator
 *
 */
public class QueryDemo {
	public static void main(String[] args) {
		/*
		 * 1、对hibernate.cfg.xml这个核心的配置文件进行建模
		 * 2、建模后的对象configure去获取sessionfactory对象,sessionfactory对象中包含了数据库相关信息
		 * 3、通过sessionfactory对象去获取session会话
		 * 4、session开启事务(查询中是不需要)
		 * 5、操作数据库
		 * 6、提交事务(查询中是不需要)
		 * 7、释放资源
		 */
		Configuration configure = new Configuration().configure("/hibernate.cfg.xml");
		SessionFactory sessionFactory = configure.buildSessionFactory();
		Session session = sessionFactory.openSession();
		List list = session.createQuery("from User").list();
		
		for (Object obj : list) {
			System.out.println(obj);
		}
		
		session.close();
	}
}


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