研究了常用的Java基本数据类型在mysql和oracle数据库的映射类型。这里使用的是包装类型做研究，一般在hibernate声明的时候最好不要用基本类型，因为数据库中的null空数据有可能映射为基本类型的时候会报错，但是映射到包装类型的时候值为null，不会报错。
1.常见数据类型在Mysql数据库的映射
实体:
package cn.qlq.domain;import java.sql.Time; import java.util.Date;public class TestType {private Long id;private Integer age;private Character sex;private Boolean isPerson;private Date birth;private Time birthTime;private String name;public Long getId() {return id;}public void setId(Long id) {this.id = id;}public Integer getAge() {return age;}public void setAge(Integer age) {this.age = age;}public Character getSex() {return sex;}public void setSex(Character sex) {this.sex = sex;}public Boolean getIsPerson() {return isPerson;}public void setIsPerson(Boolean isPerson) {this.isPerson = isPerson;}public Date getBirth() {return birth;}public void setBirth(Date birth) {this.birth = birth;}public Time getBirthTime() {return birthTime;}public void setBirthTime(Time birthTime) {this.birthTime = birthTime;}public String getName() {return name;}public void setName(String name) {this.name = name;}@Overridepublic String toString() {return "TestType [id=" + id + ", age=" + age + ", sex=" + sex + ", isPerson=" + isPerson + ", birth=" + birth+ ", birthTime=" + birthTime + ", name=" + name + "]";}}
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"><!-- 配置表与实体对象的关系 --><!-- package属性:填写一个包名.在元素内部凡是需要书写完整类名的属性,可以直接写简答类名了. --> <hibernate-mapping package="cn.qlq.domain" ><!-- class元素: 配置实体与表的对应关系的name: 完整类名table:数据库表名--><class name="TestType" table="testtype" ><!-- id元素:配置主键映射的属性name: 填写主键对应属性名column(可选): 填写表中的主键列名.默认值:列名会默认使用属性名type(可选):填写列(属性)的类型.hibernate会自动检测实体的属性类型.每个类型有三种填法: java类型|hibernate类型|数据库类型not-null(可选):配置该属性(列)是否不能为空. 默认值:falselength(可选):配置数据库中列的长度. 默认值:使用数据库类型的最大长度--><id name="id" ><!-- generator:主键生成策略 --><!--identity : 主键自增.由数据库来维护主键值.录入时不需要指定主键. --><generator class="native"></generator></id><!-- property元素:除id之外的普通属性映射name: 填写属性名column(可选): 填写列名type(可选):填写列(属性)的类型.hibernate会自动检测实体的属性类型.每个类型有三种填法: java类型|hibernate类型|数据库类型not-null(可选):配置该属性(列)是否不能为空. 默认值:falselength(可选):配置数据库中列的长度. 默认值:使用数据库类型的最大长度--><property name="age"/><property name="sex"/><property name="isPerson"/><property name="birth"/><property name="birthTime"/><property name="name"/></class> </hibernate-mapping>
Mysql映射的类型:
mysql> desc testtype; +-----------+--------------+------+-----+---------+----------------+ | Field | Type | Null | Key | Default | Extra | +-----------+--------------+------+-----+---------+----------------+ | id | bigint(20) | NO | PRI | NULL | auto_increment | | age | int(11) | YES | | NULL | | | sex | char(1) | YES | | NULL | | | isPerson | bit(1) | YES | | NULL | | | birth | datetime | YES | | NULL | | | birthTime | time | YES | | NULL | | | name | varchar(255) | YES | | NULL | | +-----------+--------------+------+-----+---------+----------------+ 7 rows in set (0.01 sec)
结果:
Long------------------------------bigint
Integer----------------------- int
Character--------------------- char
Bolean---------------------------bit
java.util.Date;--------------datetime
java.sql.Time;------------------time
String----------------------------varchar(255)
- 插入数据:
public static void main(String[] args) {//3.3以及之前的版本构建会话工厂对象 // SessionFactory sessionFactory = new Configuration().configure().buildSessionFactory();//5.0之后获取SessionFactory//创建服务注册对象ServiceRegistry serviceRegistry = new StandardServiceRegistryBuilder().configure().build();//创建会话工厂对象SessionFactory sessionFactory = new MetadataSources(serviceRegistry).buildMetadata().buildSessionFactory();//获取session对象Session session = sessionFactory.openSession();//开启事务Transaction tx = session.beginTransaction();//保存对象TestType t1 = new TestType();TestType t2 = new TestType();t1.setAge(22);t2.setAge(23);t1.setName("zhangsan");t2.setName("zhangsanhaha");t1.setSex('1');t2.setSex('2');t1.setBirth(new Date());t2.setBirth(new Date());t1.setIsPerson(true);t2.setIsPerson(false);session.save(t1);session.save(t2);tx.commit();//关闭流 session.close();sessionFactory.close();}
结果:
mysql> select * from testtype; +----+------+------+----------+---------------------+-----------+--------------+ | id | age | sex | isPerson | birth | birthTime | name | +----+------+------+----------+---------------------+-----------+--------------+ | 1 | 22 | 1 | | 2018-08-10 22:39:19 | NULL | zhangsan | | 2 | 23 | 2 | | 2018-08-10 22:39:19 | NULL | zhangsanhaha | +----+------+------+----------+---------------------+-----------+--------------+ 2 rows in set (0.00 sec)
- 查询
(1)基本查询:
@Test// HQL查询所有数据public void fun1() {// 1 获得sessionSession session = HibernateUtil.openSession();// 2.书写HQL语句 // String hql = "from cn.qlq.domain.Customer";// from 类名全路径String hql = "from TestType";// 如果整个项目中只有这一个类名可以直接写名字// 3.根据hql创建查询对象Query query = session.createQuery(hql);// 4.根据查询对象获取查询结果List<TestType> list = query.list();System.out.println(list);}
结果:
[TestType [id=1, age=22, sex=1, isPerson=true, birth=2018-08-10 22:39:19.0, birthTime=null, name=zhangsan], TestType [id=2, age=23, sex=2, isPerson=false, birth=2018-08-10 22:39:19.0, birthTime=null, name=zhangsanhaha]]
(2)条件查询:----针对上面的类型进行条件查询
@Test// HQL查询所有数据public void fun1() {// 1 获得sessionSession session = HibernateUtil.openSession();// 2.书写HQL语句 // String hql = "from cn.qlq.domain.Customer";// from 类名全路径String hql = "from TestType where age = 22 and sex = 1 and isPerson = true and name = 'zhangsan' and birth like '2018-08-10%'";// 如果整个项目中只有这一个类名可以直接写名字// 3.根据hql创建查询对象Query query = session.createQuery(hql);// 4.根据查询对象获取查询结果List<TestType> list = query.list();System.out.println(list);}
结果:
selecttesttype0_.id as id1_0_,testtype0_.age as age2_0_,testtype0_.sex as sex3_0_,testtype0_.isPerson as isPerson4_0_,testtype0_.birth as birth5_0_,testtype0_.birthTime as birthTim6_0_,testtype0_.name as name7_0_ fromtesttype testtype0_ wheretesttype0_.age=22 and testtype0_.sex=1 and testtype0_.isPerson=1 and testtype0_.name='zhangsan' and (testtype0_.birth like '2018-08-10%') [TestType [id=1, age=22, sex=1, isPerson=true, birth=2018-08-10 22:39:19.0, birthTime=null, name=zhangsan]]
补充:Mysql的boolean类型也可以用true_false表示，数据类型会变为char(1)，存的是T和F:
<property name="isPerson" type="true_false"/>
2.常见数据类型在Oracle数据库的映射
Oracle映射上面直接映射会报错，解决办法: 将boolean映射为hibernate的true_false (原理都是在数据库存T或者F，F为false，T为true)
第一种: boolean映射为yes_no
<?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"><!-- 配置表与实体对象的关系 --><!-- package属性:填写一个包名.在元素内部凡是需要书写完整类名的属性,可以直接写简答类名了. --> <hibernate-mapping package="cn.qlq.domain" ><!-- class元素: 配置实体与表的对应关系的name: 完整类名table:数据库表名--><class name="TestType" table="testtype" ><!-- id元素:配置主键映射的属性name: 填写主键对应属性名column(可选): 填写表中的主键列名.默认值:列名会默认使用属性名type(可选):填写列(属性)的类型.hibernate会自动检测实体的属性类型.每个类型有三种填法: java类型|hibernate类型|数据库类型not-null(可选):配置该属性(列)是否不能为空. 默认值:falselength(可选):配置数据库中列的长度. 默认值:使用数据库类型的最大长度--><id name="id" ><!-- generator:主键生成策略 --><!--identity : 主键自增.由数据库来维护主键值.录入时不需要指定主键. --><generator class="native"></generator></id><!-- property元素:除id之外的普通属性映射name: 填写属性名column(可选): 填写列名type(可选):填写列(属性)的类型.hibernate会自动检测实体的属性类型.每个类型有三种填法: java类型|hibernate类型|数据库类型not-null(可选):配置该属性(列)是否不能为空. 默认值:falselength(可选):配置数据库中列的长度. 默认值:使用数据库类型的最大长度--><property name="age"/><property name="sex"/> <property name="isPerson" type="true_false"/><property name="birth"/><property name="birthTime"/><property name="name"/></class> </hibernate-mapping>
结果:
总结:
Long------------------------------number
Integer----------------------- number
Character--------------------- char
Bolean---------------------------char
java.util.Date;--------------date
java.sql.Time;------------------date
String----------------------------varchar(255)
添加数据:
package cn.qlq.util;import java.util.Date;import org.hibernate.Session; import org.hibernate.SessionFactory; import org.hibernate.Transaction; import org.hibernate.boot.MetadataSources; import org.hibernate.boot.registry.StandardServiceRegistryBuilder; import org.hibernate.service.ServiceRegistry;import cn.qlq.domain.TestType;public class TestSave {public static void main(String[] args) {//3.3以及之前的版本构建会话工厂对象 // SessionFactory sessionFactory = new Configuration().configure().buildSessionFactory();//5.0之后获取SessionFactory//创建服务注册对象ServiceRegistry serviceRegistry = new StandardServiceRegistryBuilder().configure().build();//创建会话工厂对象SessionFactory sessionFactory = new MetadataSources(serviceRegistry).buildMetadata().buildSessionFactory();//获取session对象Session session = sessionFactory.openSession();//开启事务Transaction tx = session.beginTransaction();//保存对象TestType t1 = new TestType();TestType t2 = new TestType();t1.setAge(22);t2.setAge(23);t1.setName("zhangsan");t2.setName("zhangsanhaha");t1.setSex('1');t2.setSex('2');t1.setBirth(new Date());t2.setBirth(new Date());t1.setIsPerson(true);t2.setIsPerson(false);session.save(t1);session.save(t2);tx.commit();//关闭流 session.close();sessionFactory.close();} }
结果:
- 查询所有:
@Test// HQL查询所有数据public void fun1() {// 1 获得sessionSession session = HibernateUtil.openSession();// 2.书写HQL语句String hql = "from cn.qlq.domain.TestType";// from 类名全路径// 3.根据hql创建查询对象Query query = session.createQuery(hql);// 4.根据查询对象获取查询结果List<TestType> list = query.list();System.out.println(list);}
结果:
Hibernate: selecttesttype0_.id as id1_0_,testtype0_.age as age2_0_,testtype0_.sex as sex3_0_,testtype0_.isPerson as isPerson4_0_,testtype0_.birth as birth5_0_,testtype0_.birthTime as birthTim6_0_,testtype0_.name as name7_0_ fromtesttype testtype0_ [TestType [id=15, age=22, sex=1, isPerson=true, birth=2018-08-10 23:19:33.0, birthTime=null, name=zhangsan], TestType [id=16, age=23, sex=2, isPerson=false, birth=2018-08-10 23:19:33.0, birthTime=null, name=zhangsanhaha]]
- 按上面的条件查询:
@Test// HQL查询所有数据public void fun1() {// 1 获得sessionSession session = HibernateUtil.openSession();// 2.书写HQL语句String hql = "from TestType where age = 22 and sex = 1 and isPerson = true and name = 'zhangsan'";// 如果整个项目中只有这一个类名可以直接写名字// 3.根据hql创建查询对象Query query = session.createQuery(hql);// 4.根据查询对象获取查询结果List<TestType> list = query.list();System.out.println(list);}
结果: (日期不能直接like了)
Hibernate: selecttesttype0_.id as id1_0_,testtype0_.age as age2_0_,testtype0_.sex as sex3_0_,testtype0_.isPerson as isPerson4_0_,testtype0_.birth as birth5_0_,testtype0_.birthTime as birthTim6_0_,testtype0_.name as name7_0_ fromtesttype testtype0_ wheretesttype0_.age=22 and testtype0_.sex=1 and testtype0_.isPerson='T' and testtype0_.name='zhangsan' [TestType [id=15, age=22, sex=1, isPerson=true, birth=2018-08-10 23:19:33.0, birthTime=null, name=zhangsan]]
总结:
对于mysql和oracle的boolean的通用类型就是true_false，hibernate会将字段类型设置为char(1)，然后true的时候存T，false的时候存F。
