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目录
Hibernate.xml
1、数据库的基本信息。
2、集成 C3P0,设置数据库连接池信息。
3、Hibernate 基本信息。
4、注册实体关系映射文件。
实体关系映射文件 (实体类文件名.hbm.xml)
1、hibernate-mapping标签的属性
2、class标签的属性
2.1、dynamic-insert:动态添加 (默认为false)
2.2、dynamic-update:动态更新(默认为false)
2.3、where:查询时给 SQL 添加 where 条件
- hibernate.cfg.xml
- hbm.xml
Hibernate.xml
hibernate.xml 配置 Hibernate 的全局环境。
<?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>
<!-- 数据源配置 -->
<property name="connection.username">root</property>
<property name="connection.password">root</property>
<property
name="connection.driver_class">com.mysql.cj.jdbc.Driver</property>
<property name="connection.url">jdbc:mysql://localhost:3306/test?
useUnicode=true&characterEncoding=UTF-8</property>
<!-- C3P0 -->
<property name="hibernate.c3p0.acquire_increment">10</property>
<property name="hibernate.c3p0.idle_test_period">10000</property>
<property name="hibernate.c3p0.timeout">5000</property>
<property name="hibernate.c3p0.max_size">30</property>
<property name="hibernate.c3p0.min_size">5</property>
<property name="hibernate.c3p0.max_statements">10</property>
<!-- 数据库⽅⾔ -->
<property name="dialect">org.hibernate.dialect.MySQLDialect</property>
<!-- 打印SQL -->
<property name="show_sql">true</property>
<!-- 格式化SQL -->
<property name="format_sql">true</property>
<!-- 是否⾃动⽣成数据库 -->
<property name="hibernate.hbm2ddl.auto"></property>
<!-- 注册实体关系映射⽂件 -->
<mapping resource="com/southwind/entity/People.hbm.xml"></mapping>
<mapping resource="com/southwind/entity/Customer.hbm.xml"></mapping>
<mapping resource="com/southwind/entity/Orders.hbm.xml"></mapping>
<mapping resource="com/southwind/entity/Account.hbm.xml"></mapping>
<mapping resource="com/southwind/entity/Course.hbm.xml"></mapping>
</session-factory>
</hibernate-configuration>
1、数据库的基本信息。
<property name="connection.username">root</property>
<property name="connection.password">root</property>
<property name="connection.driver_class">com.mysql.cj.jdbc.Driver</property>
<property name="connection.url">jdbc:mysql://localhost:3306/test?
useUnicode=true&characterEncoding=UTF-8</property>
2、集成 C3P0,设置数据库连接池信息。
<property name="hibernate.c3p0.acquire_increment">10</property>
<property name="hibernate.c3p0.idle_test_period">10000</property>
<property name="hibernate.c3p0.timeout">5000</property>
<property name="hibernate.c3p0.max_size">30</property>
<property name="hibernate.c3p0.min_size">5</property>
<property name="hibernate.c3p0.max_statements">10</property>
3、Hibernate 基本信息。
<!-- 数据库⽅⾔ -->
<property name="dialect">org.hibernate.dialect.MySQLDialect</property>
<!-- 打印SQL -->
<property name="show_sql">true</property>
<!-- 格式化SQL -->
<property name="format_sql">true</property>
<!-- 是否⾃动⽣成数据库 -->
<property name="hibernate.hbm2ddl.auto">update</property>
hibernate.hbm2ddl.auto 属性的可选值:
- update:动态创建表,如果表存在,则直接使⽤,如果表不存在,则创建。
- create:⽆论表是否存在,都会重新创建。
- create-drop:初始化创建表,程序结束时删除表。
- validate:校验实体关系映射⽂件和数据表是否对应,不能对应直接报错。
4、注册实体关系映射文件。
<!-- 注册实体关系映射⽂件 -->
<mapping resource="com/southwind/entity/People.hbm.xml"></mapping>
<mapping resource="com/southwind/entity/Customer.hbm.xml"></mapping>
<mapping resource="com/southwind/entity/Orders.hbm.xml"></mapping>
<mapping resource="com/southwind/entity/Account.hbm.xml"></mapping>
<mapping resource="com/southwind/entity/Course.hbm.xml"></mapping>
实体关系映射文件 (实体类文件名.hbm.xml)
<?xml version="1.0"?>
<!DOCTYPE hibernate-mapping PUBLIC "-//Hibernate/Hibernate Mapping DTD
3.0//EN"
"http://hibernate.sourceforge.net/hibernate-mapping-3.0.dtd">
<hibernate-mapping>
<class name="com.southwind.entity.Course" table="t_course">
<id name="id" type="java.lang.Integer">
<column name="id"></column>
<generator class="identity"></generator>
</id>
<property name="name" type="java.lang.String">
<column name="name"></column>
</property>
<set name="accounts" table="account_course" lazy="false">
<key column="cid"></key>
<many-to-many class="com.southwind.entity.Account" column="aid">
</many-to-many>
</set>
</class>
</hibernate-mapping>
1、hibernate-mapping标签的属性
- package:给 class 节点对应的实体类统⼀设置包名,此处设置包名,class 的 name 属性就可以 省略包名。
- schema:数据库 schema 的名称
- catalog:数据库 catalog 的名称
- default-cascade:默认的级联关系,默认为 none
- default-access:Hibernate ⽤来访问属性的策略
- default-lazy:指定了未明确注明 lazy 属性的 Java 属性和集合类,Hibernate 会采⽤什么样的加载 ⻛格,默认为 true
- auto-import:指定我们是否可以在查询语句中使⽤⾮全限定类名,默认为 true,如果项⽬中有两 个同名的持久化类,最好在这两个类的对应映射⽂件中国配置为 false
2、class标签的属性
- name:实体类名
- table:数据表名
- schema:数据库 schema 的名称,会覆盖 hibernate-mapping 的 schema
- catalog:数据库 catalog 的名称,会覆盖 hibernate-mapping 的 catalog
- proxy:指定⼀个接⼝,在延迟加载时作为代理使⽤
- dynamic-update:动态更新(默认为false)
- dynamic-insert:动态添加 (默认为false)
2.1、dynamic-insert:动态添加 (默认为false)
package com.southwind.test;
import com.southwind.entity.Account;
import com.southwind.entity.People;
import org.hibernate.Session;
import org.hibernate.SessionFactory;
import org.hibernate.cfg.Configuration;
public class Test8 {
public static void main(String[] args) {
//创建 Configuration
Configuration configuration = new
Configuration().configure("hibernate.xml");
//获取 SessionFactory
SessionFactory sessionFactory = configuration.buildSessionFactory();
//获取 Session
Session session = sessionFactory.openSession();
People people = new People();
people.setName("张三");
session.save(people);
session.close();
}
}
dynamic-insert=false
dynamic-insert=true
<class name="com.southwind.entity.People" table="people" dynamicinsert="true">
2.2、dynamic-update:动态更新(默认为false)
public class Test8 {
public static void main(String[] args) {
//创建 Configuration
Configuration configuration = new
Configuration().configure("hibernate.xml");
//获取 SessionFactory
SessionFactory sessionFactory = configuration.buildSessionFactory();
//获取 Session
Session session = sessionFactory.openSession();
People people = session.get(People.class,6);
people.setMoney(2000.0);
session.update(people);
session.beginTransaction().commit();
session.close();
}
}
dynamic-update=false
dynamic-update=true
<class name="com.southwind.entity.People" table="people" dynamic-insert="true"
dynamic-update="true">
2.3、where:查询时给 SQL 添加 where 条件
import com.southwind.entity.Account;
import com.southwind.entity.People;
import org.hibernate.Session;
import org.hibernate.SessionFactory;
import org.hibernate.cfg.Configuration;
import org.hibernate.query.Query;
import java.util.List;
public class Test8 {
public static void main(String[] args) {
//创建 Configuration
Configuration configuration = new
Configuration().configure("hibernate.xml");
//获取 SessionFactory
SessionFactory sessionFactory = configuration.buildSessionFactory();
//获取 Session
Session session = sessionFactory.openSession();
String hql = "from People";
Query query = session.createQuery(hql);
List<People> list = query.list();
for (People people:list) {
System.out.println(people);
}
session.beginTransaction().commit();
session.close();
}
}
设置where属性之前
设置where属性之后
<class name="com.southwind.entity.People" table="people" dynamic-insert="true"
dynamic-update="true" where="id = 6">
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