Hibernate二次学习一----------搭建Hibernate

Hibernate

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1. 项目结构

• 本项目使用maven进行项目管理，搭建一个简单的Hibernate框架需要四步。
• 本项目未使用注解方式进行搭建

1.1 pom.xml

• 使用maven引入依赖jar包，若未使用maven，则自己下载所需jar包放到lib目录下

<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>org.imooc</groupId>
    <artifactId>Hibernate_001</artifactId>
    <version>0.0.1-SNAPSHOT</version>
    <packaging>jar</packaging>
    <properties>
        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
    </properties>
    <dependencies>
        <!-- junit -->
        <dependency>
            <groupId>junit</groupId>
            <artifactId>junit</artifactId>
            <version>4.12</version>
            <scope>test</scope>
        </dependency>
        <!-- Hibernate -->
        <dependency>
            <groupId>org.hibernate</groupId>
            <artifactId>hibernate-core</artifactId>
            <version>5.1.5.Final</version>
        </dependency>
        <!-- mysql-connector-java -->
        <dependency>
            <groupId>mysql</groupId>
            <artifactId>mysql-connector-java</artifactId>
            <version>5.1.22</version>
        </dependency>
    </dependencies>
    <build>
        <plugins>
            <plugin>
                <groupId>org.apache.maven.plugins</groupId>
                <artifactId>maven-compiler-plugin</artifactId>
                <version>3.6.1</version>
                <configuration>
                    <target>1.7</target>
                    <source>1.7</source>
                    <encoding>UTF-8</encoding>
                </configuration>
            </plugin>
        </plugins>
    </build>
</project>

1.2 hibernate.cfg.xml

• 在hibernate.cfg.xml中配置三方面的信息。
  
  • 连接数据库的信息，比如驱动、url、连接名、密码等。
  • hibernate本身的配置，比如方言、是否展示SQL，SQL格式化、建表策略等。
  • 引入映射文件

<?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>
        <!-- 数据库连接名 -->
        <property name="connection.username">root</property>
        <!-- 数据库连接密码 -->
        <property name="connection.password">20121221</property>
        <!-- 数据库驱动 -->
        <property name="connection.driver_class">com.mysql.jdbc.Driver</property>
        <!-- 数据库连接url -->
        <property name="connection.url">
            jdbc:mysql://localhost:3306/hibernate?useSSL=true&amp;useUnicode=true&amp;characterEncoding=UTF-8
        </property>
        <!-- 方言 -->
        <property name="dialect">org.hibernate.dialect.MySQL5InnoDBDialect</property>
        <!-- 展示SQL -->
        <property name="show_sql">true</property>
        <!-- 格式化SQL -->
        <property name="format_sql">false</property>
        <!-- 建表策略 -->
        <property name="hbm2ddl.auto">update</property>
        <!-- 指定映射文件 -->
        <mapping resource="hbm/student.hbm.xml"/>
    </session-factory>
</hibernate-configuration>

1.3 entity

• entity是实体类，对应数据库中的表结构，仅实现setter和getter方法即可

package com.imooc.hibernate.model;
import java.util.Date;
public class Student {
    private int sid; // 学号
    private String sname; // 姓名
    private String gender; // 性别
    private Date birthday; // 出生日期
    private String address; // 地址
    public Student() {
    }
    public Student(int sid, String sname, String gender, Date birthday, String address) {
        this.sid = sid;
        this.sname = sname;
        this.gender = gender;
        this.birthday = birthday;
        this.address = address;
    }
    public int getSid() {
        return sid;
    }
    public void setSid(int sid) {
        this.sid = sid;
    }
    public String getSname() {
        return sname;
    }
    public void setSname(String sname) {
        this.sname = sname;
    }
    public String getGender() {
        return gender;
    }
    public void setGender(String gender) {
        this.gender = gender;
    }
    public Date getBirthday() {
        return birthday;
    }
    public void setBirthday(Date birthday) {
        this.birthday = birthday;
    }
    public String getAddress() {
        return address;
    }
    public void setAddress(String address) {
        this.address = address;
    }
    @Override
    public String toString() {
        return "Student [sid=" + sid + ", sname=" + sname + ", gender=" 
                + gender + ", birthday=" + birthday + ", address=" + address + "]";
    }
}

1.4 entity.hbm.xml

• entity.hbm.xml是映射文件，将数据库表与entity进行对应

<?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 name="com.imooc.hibernate.model.Student">
        <id name="sid" type="int">
            <column name="SID"/>
            <generator class="assigned"/> <!-- 主键生成策略 -->
        </id>
        <property name="sname" type="java.lang.String">
            <column name="SNAME"/>
        </property>
        <property name="gender" type="java.lang.String">
            <column name="GENDER"></column>
        </property>
        <property name="birthday" type="java.util.Date">
            <column name="BIRTHDAY"/>
        </property>
        <property name="address" type="java.lang.String">
            <column name="ADDRESS"></column>
        </property>
    </class>
</hibernate-mapping>

2. 测试

• 使用junit进行测试

package com.imooc.hibernate.test;
import java.util.Date;
import org.hibernate.Session;
import org.hibernate.SessionFactory;
import org.hibernate.Transaction;
import org.hibernate.cfg.Configuration;
import org.junit.After;
import org.junit.Before;
import org.junit.Test;
import com.imooc.hibernate.model.Student;
public class StudentTest {
    private SessionFactory sessionFactory;
    private Session session;
    private Transaction transaction;
    @Test
    public void testSaveStudent() {
        // 生成学生对象
        Student s = new Student(3, "张三丰", "男", new Date(), "武当山");
        session.save(s);
    }
    @Before
    public void init() {
        // 创建会话工厂对象
        sessionFactory = new Configuration().configure().buildSessionFactory();
        // 创建会话对象
        session = sessionFactory.openSession();
        // 开始事务
        transaction = session.beginTransaction();
    }
    @After
    public void destory () {
        // 提交事务
        transaction.commit();
        // 关闭会话
        session.close();
        // 关闭会话工厂
        sessionFactory.close();
    }
}

3. 总结

Hibernate初步搭建很简单，主要是使用hibernate.cfg.xml进行数据库连接的配置，使用entity.hbm.xml进行数据库表结构与实体类进行映射。

参考：Hibernate初探之单表映射