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

用Hibernate来完成增删改查
下面我们导入pom.xml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.zl</groupId>
  <artifactId>hibernate1</artifactId>
  <packaging>war</packaging>
  <version>0.0.1-SNAPSHOT</version>
  <name>hibernate1 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>${mysql.driver.version}</version>
        </dependency>
        <dependency>
            <groupId>org.apache.tomcat</groupId>
            <artifactId>tomcat-jsp-api</artifactId>
            <version>8.0.47</version>
        </dependency>
  </dependencies>
  <build>
    <finalName>hibernate1</finalName>
    <plugins>
            <plugin>
                <groupId>org.apache.maven.plugins</groupId>
                <artifactId>maven-compiler-plugin</artifactId>
                <version>3.7.0</version>
                <configuration>
                    <source>${maven.compiler.source}</source>
                    <target>${maven.compiler.target}</target>
                    <encoding>${project.build.sourceEncoding}</encoding>
                </configuration>
            </plugin>
        </plugins>
  </build>
</project>

　　

核心配置文件 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://localhost:3306/sys?useUnicode=true&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/zl/entity/User.hbm.xml"/>
       </session-factory>
    </hibernate-configuration>

　　

接下来我们要创建一个实体类User 

package com.zl.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();
        // TODO Auto-generated constructor stub
    }
    
}

　　

写一个实体映射文件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标签中的 name：实体类的全路径名   table:实体类对应的数据库表  
id标签:name：实体类中的属性（映射的是表的主键）
       type：属性对应的类型
       column:属性对应该=的表中的那个列段
property
       name：实体类中的属性（映射的是表的非主键）
       type：属性对应的类型
       column:属性对应该=的表中的那个列段
 List list = session.createQuery("from User").list();
 为什么我们可以得出一个list集合
 1，建模hibernate.cfg.xml对象 从中拿到了com/zl/one/entity/User.hbm.xml
 2,建模了User.hbm.xml这个文件拿到了com.zl.one.entity.User拿到了它并且拿到t_hibernate_user
 3.User user=class.forName("com.zl.one.entity.User").newInstance();
 拿到User对象 然后Fild  f=euser.getClass("userName");
  select user_name,user_pwd,... from t_hibernate_user

Fild  userNameFild=user.getClass("userName");
Fild userPwdFild=user.getClass("userpwd");
13	xxx	123456	xxx	1	2018-11-17 00:00:00	2018-11-17 09:48:48	xxx
14	精华	123456	金燕	女		2018-11-18 09:24:38	开小差

UserNameField.set(user,精华)
UserPwdField.set(user,123456)
最后user中的所有属性之都有了
4.循环上一步操作，最终所有user实咧都放入list集合中List list
 -->

 <class name="com.zl.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-mapping>

　　

然后接下来我们就该写增删改查了
　查询

package com.zl.test;

import java.util.List;

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

/**
 * hibernate 中查询案例
 * @author zl
 *
 */
public class QueryDemo {

    public static void main(String[] args) {
        //对hibernate.cfg.xml进行建模拿到sessionfactory工厂(两步)
        Configuration configure = new Configuration().configure("/hibernate.cfg.xml");
        SessionFactory sessionFactory = configure.buildSessionFactory();
        //通过工厂获取到session会话(操作数据库的)
        Session session = sessionFactory.openSession();
        //直接操作数据库
        List list = session.createQuery("from User").list();
        for (Object obj : list) {
            System.out.println(obj);
        }
        //关闭数据库
        session.close();
    }
}

　　

　增加

package com.zl.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.zl.entity.User;

/**
 * hibernate 中增加案例
 * @author zl
 *
 */
public class AddDemo {

    public static void main(String[] args) {
        //对hibernate.cfg.xml进行建模拿到sessionfactory工厂(两步)
        Configuration configure = new Configuration().configure("/hibernate.cfg.xml");
        SessionFactory sessionFactory = configure.buildSessionFactory();
        //通过工厂获取到session会话(操作数据库的)
        Session session = sessionFactory.openSession();
        //获取事务对象
        Transaction Transaction = session.beginTransaction();
        //直接操作数据库
        session.save(new User("zl", "123456","王五", "男", new Date(System.currentTimeMillis()),new Timestamp(System.currentTimeMillis()), "暂无介绍"));
        //提交事务
        Transaction.commit();
        //关闭数据库
        session.close();

    }
}

　　

 修改

package com.zl.test;

import java.io.Serializable;
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.zl.entity.User;

/**
 * hibernate 中修改案例
 * @author zl
 *
 */
public class EditDemo {

    public static void main(String[] args) {
        //对hibernate.cfg.xml进行建模拿到sessionfactory工厂(两步)
        Configuration configure = new Configuration().configure("/hibernate.cfg.xml");
        SessionFactory sessionFactory = configure.buildSessionFactory();
        //通过工厂获取到session会话(操作数据库的)
        Session session = sessionFactory.openSession();
        //获取事务对象
        Transaction Transaction = session.beginTransaction();
        //直接操作数据库
        User user = new User("zl2", "123456","王五2", "男", new Date(System.currentTimeMillis()),new Timestamp(System.currentTimeMillis()), "暂无介绍2");
        user.setId(15);
        session.update(user);
//        User user = session.get(User.class,15);
//        System.out.println(user);
//        user.setRealName("zl3");
        
        //提交事务
        Transaction.commit();
        //关闭数据库
        session.close();
    }
}

　　

删除

package com.zl.test;

import java.io.Serializable;
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.zl.entity.User;

/**
 * hibernate 中删除案例
 * @author zl
 *
 */
public class DelDemo {

    public static void main(String[] args) {
        //对hibernate.cfg.xml进行建模拿到sessionfactory工厂(两步)
        Configuration configure = new Configuration().configure("/hibernate.cfg.xml");
        SessionFactory sessionFactory = configure.buildSessionFactory();
        //通过工厂获取到session会话(操作数据库的)
        Session session = sessionFactory.openSession();
        //获取事务对象
        Transaction Transaction = session.beginTransaction();
        //直接操作数据库
        User user=new User();
        user.setId(15);
        session.delete(user);
        //提交事务
        Transaction.commit();
        //关闭数据库
        session.close();
    }
}