Hibernate——（4）Hibernate映射类型

一、常用的Hibernat映射类型有如下几种：

• string
• integer
• double
• date    日期，只表示年月日
• datetime 日期，只表示年月日
• timestamp  时间戳，存放年月日时分秒
• yes_no  将在数据库中存放一个字符“Y"或“N”
• true_false  将在数据库中存放一个字符“T"或者"F".

二、案例

1、新建数据库表

DROP TABLE IF EXISTS t_emp;
CREATE TABLE t_emp (
t_id
int(11) NOT NULL AUTO_INCREMENT,
t_name
varchar(50) NOT NULL,
t_salary
double(9,2) NOT NULL,
t_hire_date date
NOT NULL,
t_last_login timestamp
NOT NULL,
t_register char(1)
NOT NULL,
PRIMARY KEY (t_id)
) ENGINE=InnoDB;

varchar对应String

date对应年月日

timestamp对应年月日时分秒

通常情况下，使用char(1),值为true/false,来表示Boolean类型。

2、新建POJO类Emp

package com.xsyu.tts.po;

import java.util.Date;

public class Emp {
	private Integer id;
	private String name;
	private double salary;
	private Date hireDate;
	// 入职时间
	private Date lastLogin;
	// 最后登录日期
	private boolean register;

	// 是否注册
	public Integer getId() {
		return id;
	}

	public void setId(Integer id) {
		this.id = id;
	}

	public String getName() {
		return name;
	}

	public void setName(String name) {
		this.name = name;
	}

	public double getSalary() {
		return salary;
	}

	public void setSalary(double salary) {
		this.salary = salary;
	}

	public Date getHireDate() {
		return hireDate;
	}

	public void setHireDate(Date hireDate) {
		this.hireDate = hireDate;
	}

	public Date getLastLogin() {
		return lastLogin;
	}

	public void setLastLogin(Date lastLogin) {
		this.lastLogin = lastLogin;
	}

	public boolean isRegister() {
		return register;
	}

	public void setRegister(boolean register) {
		this.register = register;
	}
}

3、新建Emp.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">
<hibernate-mapping package="com.tarena.tts.po">
	<class name="Emp" table="t_emp">
		<id name="id" type="integer" column="t_id">
			<!-- 用来指明主键的生成方式 -->
			<generator class="identity">
			</generator>
		</id>
		<property name="name" type="string" column="t_name" />
		<property name="salary" type="double" column="t_salary" />
		<property name="hireDate" type="date" column="t_hire_date" />
		<property name="lastLogin" type="timestamp" column="t_last_login" />
		<property name="register" type="yes_no" column="t_register" />
	</class>
</hibernate-mapping>

4、修改配置文件

<?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-configuration>
	<session-factory>
		<!-- 数据库连接信息 -->
		<property name="connection.url">
			jdbc:mysql://localhost:3306/test
		</property>
		<property name="connection.username">root</property>
		<property name="connection.password">root</property>
		<property name="connection.driver_class">
			com.mysql.jdbc.Driver
		</property>
		<!-- Hibernate配置信息 -->
		<!-- dialect方言，用亍配置生成针对哪个数据库的SQL语句 -->
		<property name="dialect">
			<!--方言类，Hibernate提供的，用亍封装某种特定数据库的方言 -->
			org.hibernate.dialect.MySQLDialect
		</property>
		<property name="hibernate.show_sql">true</property>
		<!-- 在配置文件中关联映射文件 -->
		<mapping resource="com/xsyu/tts/po/User.hbm.xml" />
		<mapping resource="com/xsyu/tts/po/Foo.hbm.xml" />
		<mapping resource="com/xsyu/tts/po/Emp.hbm.xml" />
	</session-factory>
</hibernate-configuration>

5、修改TestPersistence

	/**
	 * 用于测试Hibernate映射类型 string interger double date timestamp yes_no true_false
	 */
	@Test
	public void testType() {
		Session session = HibernateUtils.openSession();
		Transaction tx = session.beginTransaction();
		Emp emp = new Emp();
		emp.setName("BigYellow");
		emp.setSalary(15000.90);
		emp.setHireDate(new Date());
		emp.setLastLogin(new Date());
		emp.setRegister(true);
		session.save(emp);
		tx.commit();
		session.close();
	}