Hibernate入门10_二级缓存02_集合级别

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>    <!-- 磁盘的存储路径，当ehcache需要把数据写到硬盘上，把数据写在这个目录 -->    <diskStore path="E:\\ehcache"/>    <!-- 默认的缓存策略 -->    <defaultCache        maxElementsInMemory="10000"        eternal="false"        timeToIdleSeconds="120"        timeToLiveSeconds="120"        overflowToDisk="true"        />    <!-- 自定义具体的命名缓存策略，每个命名缓存代表着一个缓存区域         name-设置缓存的名字，取值为全类名或者集合的名字        maxInMemory-设计基于内存的缓存中可存放的对象的最大数目        eternal-设置对象是否为永久的，true：永不过期，此时将忽略timeToIdleSeconds和timeToLiveSeconds属性 ，默认为false        timeToIdleSeconds-设置对象最长的空闲时间，单位为秒        timeToLiveSeconds-设置对象的最长的生存时间，如果为0，表示对象可以无限期的留在缓存中        overflowToDisk-缓存中的对象达到上限后，是否把溢出的对象写到硬盘缓存中,session关闭的时候缓存会被清除    -->    <cache name="com.hibernate.entities.Employee"        maxElementsInMemory="10000"        eternal="false"        timeToIdleSeconds="300"        timeToLiveSeconds="600"        overflowToDisk="true"        />    <cache name="com.hibernate.entities.Department.employees"        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>        <!-- 配置使用查询缓存 -->        <property name="cache.use_query_cache">true</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.Department"/>         <class-cache usage="read-write" class="com.hibernate.entities.Employee"/>        <collection-cache usage="read-write" collection="com.hibernate.entities.Department.employees"/>    </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.Iterator;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-集合级别     */    @Test    public void testCollectionSecondLevelCache(){        Department department1 = (Department) session.get(Department.class, 27);        System.out.println(department1);        System.out.println(department1.getEmployees().size());        transaction.commit();        session.close();        session = sessionFactory.openSession();        transaction = session.beginTransaction();        Department department2 = (Department) session.get(Department.class, 27);        System.out.println(department2);        System.out.println(department2.getEmployees().size());    }     /***     * 查询缓存     */    @Test    public void testQueryCache(){        Query query = session.createQuery("FROM Employee");        query.setCacheable(true);//设置使用查询缓存，需要配置文件实现声明才有效        List<Employee> employees = query.list();        System.out.println(employees.size());        employees = query.list();        System.out.println(employees.size());    }    /***     * 更新时间戳缓存     */    @Test    public void testUpdateTimeStampCache(){        Query query = session.createQuery("FROM Employee");        query.setCacheable(true);//设置使用查询缓存，需要配置文件实现声明才有效        List<Employee> employees = query.list();        System.out.println(employees.size());        Employee employee = (Employee) session.get(Employee.class, 59);        employee.setSalary(30000f);        employees = query.list();        System.out.println(employees.size());    }    /***     * 使用了查询二级缓存后，使用Iterate查询能稍微提高性能，不建议使用     */    @Test    public void testQueryIterater(){        Department department1 = (Department) session.get(Department.class, 27);        System.out.println(department1);        System.out.println(department1.getEmployees().size());        Query query = session.createQuery("FROM Employee e WHERE e.dept.id = 27");//      List<Employee> employees = query.list();//      System.out.println(employees.size());        Iterator<Employee> emps = query.iterate();        while (emps.hasNext()) {            System.out.println(emps.next().getName());        }    }    @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();    }}