Hibernate入门10

一、测试项目目录

二、代码

public class Department { private Integer id; private String name; private Set<Employee> employees = new HashSet<>(); //get/set... }

Department.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"> <!-- Generated 2017-4-4 15:42:11 by Hibernate Tools 3.4.0.CR1 --> <hibernate-mapping> <class name="com.hibernate.entities.Department" table="DEPARTMENT"> <id name="id" type="java.lang.Integer"> <column name="ID" /> <generator class="native" /> </id> <property name="name" type="java.lang.String"> <column name="NAME" /> </property> <set name="employees" table="EMPLOYEES" inverse="true" lazy="true"> <key> <column name="DEPT_ID" /> </key> <one-to-many class="com.hibernate.entities.Employee" /> </set> </class> </hibernate-mapping> public class Employee { private Integer id; private String name; private float salary; private String email; private Department dept; public Employee() { } public Employee( String email, float salary,Department dept) { super(); this.salary = salary; this.email = email; this.dept = dept; } //get/set... }

Employee.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"> <!-- Generated 2017-4-4 15:42:11 by Hibernate Tools 3.4.0.CR1 --> <hibernate-mapping> <class name="com.hibernate.entities.Employee" table="EMPLOYEES"> <!-- <cache usage="read-write"/> --> <id name="id" type="java.lang.Integer"> <column name="ID" /> <generator class="native" /> </id> <property name="name" type="java.lang.String"> <column name="NAME" /> </property> <property name="salary" type="float"> <column name="SALARY" /> </property> <property name="email" type="java.lang.String"> <column name="EMAIL" /> </property> <many-to-one name="dept" class="com.hibernate.entities.Department" fetch="join"> <column name="DEPT_ID" /> </many-to-one> </class> <query name="salaryEmps"><![CDATA[FROM Employee e WHERE e.salary > :minSalart AND e.salary < :maxSalary]]></query> </hibernate-mapping>

ehcache.xml,这个文件是二级缓存的配置文件

<ehcache> <defaultCache maxElementsInMemory="10000" eternal="false" timeToIdleSeconds="120" timeToLiveSeconds="120" overflowToDisk="true" /> <cache name="sampleCache1" maxElementsInMemory="10000" eternal="false" timeToIdleSeconds="300" timeToLiveSeconds="600" overflowToDisk="true" /> <cache name="sampleCache2" maxElementsInMemory="1000" eternal="true" timeToIdleSeconds="0" timeToLiveSeconds="0" overflowToDisk="false" /> </ehcache>

hibernate.cfg.xml

<?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> <!-- 配置链接数据库的基本信息 --> <property name="connection.username">root</property> <property name="connection.password">root</property> <property name="connection.driver_class">com.mysql.jdbc.Driver</property> <property name="connection.url">jdbc:mysql://localhost:3306/hibernate01</property> <!-- hibernate的基本信息 --> <!-- hibernate使用的数据库方言 --> <property name="dialect">org.hibernate.dialect.MySQL5InnoDBDialect</property> <!-- 执行操作时是否在控制台打印sql语句 --> <property name="show_sql">true</property> <!-- 是否对sql进行格式化 --> <property name="format_sql">true</property> <!-- 指定自动生成数据表的策略 --> <property name="hbm2ddl.auto">update</property> <!-- 设置hibernate的隔离级别 --> <property name="connection.isolation">2</property> <!-- 删除对象后，设置其OID为null --> <property name="use_identifier_rollback">true</property> <!-- 配置C3P0数据源 --> <property name="c3p0.max_size">100</property> <property name="c3p0.min_size">5</property> <property name="c3p0.acquire_increment">2</property> <property name="c3p0.idle_test_period">2000</property> <property name="c3p0.timeout">2000</property> <property name="c3p0.max_statements">10</property> <!-- 设置JDBC的statement读取数据库的时候每次从数据库中读取记录条数，这个值100合适，太大会损耗内存，小了速度慢 --> <property name="jdbc.fetch_size">100</property> <!-- 设置数据库进行批量删除，更新，插入的时候批次的大小，30比较合适 --> <property name="jdbc.batch_size">30</property> <!-- 使用二级缓存 --> <property name="cache.use_second_level_cache">true</property> <!-- 二级缓存的配置 --> <property name="hibernate.cache.region.factory_class">org.hibernate.cache.ehcache.EhCacheRegionFactory</property> <!-- 指定关联的hbm.xml文件 --> <mapping resource="com/hibernate/entities/Department.hbm.xml"/> <mapping resource="com/hibernate/entities/Employee.hbm.xml"/> <!-- 配置使用二级缓存的类 需放在mapping下面,也可以在类对应的.hbm.xml文件中配置--> <class-cache usage="read-write" class="com.hibernate.entities.Employee"/> </session-factory> </hibernate-configuration>

三、测试代码

package com.hibernate.test; import static org.junit.Assert.*; import java.nio.channels.SeekableByteChannel; import java.util.ArrayList; import java.util.Arrays; import java.util.List; import java.util.Set; import org.hibernate.Criteria; import org.hibernate.Query; import org.hibernate.Session; import org.hibernate.SessionFactory; import org.hibernate.Transaction; import org.hibernate.cfg.Configuration; import org.hibernate.criterion.Conjunction; import org.hibernate.criterion.Criterion; import org.hibernate.criterion.Disjunction; import org.hibernate.criterion.MatchMode; import org.hibernate.criterion.Restrictions; import org.hibernate.service.ServiceRegistry; import org.hibernate.service.ServiceRegistryBuilder; import org.junit.After; import org.junit.Before; import org.junit.Test; import com.hibernate.entities.Department; import com.hibernate.entities.Employee; import javassist.expr.NewArray; public class HibernateTest { private SessionFactory sessionFactory; private Session session; private Transaction transaction; @Test public void testSave() { List<Department> departments = new ArrayList<>(); for (int i = 0; i < 26; i++) { Department department = new Department(); department.setName("DEPT_" + ("A" + i)); departments.add(department); Employee employee1 = new Employee(); employee1.setName("EMP1_" + ("a" + i)); employee1.setEmail("EMAIL1_" + ("a" + i)); employee1.setSalary(1000 + i); employee1.setDept(departments.get(i)); Employee employee2 = new Employee(); employee2.setName("EMP2_" + ("b" + i)); employee2.setEmail("EMAIL2_" + ("b" + i)); employee2.setSalary(2000 + i); employee2.setDept(departments.get(i)); department.getEmployees().add(employee1); department.getEmployees().add(employee2); employee1.setDept(department); employee2.setDept(department); session.save(department); session.save(employee1); session.save(employee2); } } /*** * 二级缓存 */ @Test public void testSecondLevelCache(){ Employee employee1 = (Employee) session.get(Employee.class, 54); System.out.println(employee1); transaction.commit(); session.close(); session = sessionFactory.openSession(); transaction = session.beginTransaction(); Employee employee2 = (Employee) session.get(Employee.class, 54); System.out.println(employee2); Employee employee3 = (Employee) session.get(Employee.class, 54); System.out.println(employee3); } @Before public void init() { System.out.println("HibernateTest.init()"); // 1.创建一个sessionFactory对象 Configuration configuration = new Configuration().configure(); ServiceRegistry serviceRegistry = new ServiceRegistryBuilder().applySettings(configuration.getProperties()) .buildServiceRegistry(); sessionFactory = configuration.buildSessionFactory(serviceRegistry); // 2.创建一个session对象 session = sessionFactory.openSession(); // 3.开启事务 transaction = session.beginTransaction(); } @After public void destroy() { // 5.提交事务 transaction.commit(); // 6.关闭session session.close(); // 7.关闭SessionFactory sessionFactory.close(); } }