Spring使用系列--JPA二级缓存的使用

本示例是基于maven的项目

（1）需要添加的maven依赖

 

        <dependency>
            <groupId>org.springframework.data</groupId>
            <artifactId>spring-data-jpa</artifactId>
            <version>1.11.3.RELEASE</version>
        </dependency>
        <dependency>
            <groupId>org.hibernate</groupId>
            <artifactId>hibernate-core</artifactId>
            <version>5.1.0.Final</version>
        </dependency>
        <dependency>
            <groupId>org.hibernate</groupId>
            <artifactId>hibernate-entitymanager</artifactId>
            <version>5.1.0.Final</version>
        </dependency>
        <dependency>
            <groupId>org.hibernate</groupId>
            <artifactId>hibernate-ehcache</artifactId>
            <version>5.1.0.Final</version>
        </dependency>
        <dependency>
            <groupId>net.sf.ehcache</groupId>
            <artifactId>ehcache-core</artifactId>
            <version>2.4.3</version>
        </dependency>

（2）在applicationContext.xml中启用二级缓存

 

 

   <bean id="entityManagerFactory" class="org.springframework.orm.jpa.LocalContainerEntityManagerFactoryBean">
        <property name="dataSource" ref="dataSource"/>
        <property name="jpaVendorAdapter">
            <bean class="org.springframework.orm.jpa.vendor.HibernateJpaVendorAdapter"/>
        </property>
        <property name="packagesToScan" value="com.hongtu"/>
        <property name="jpaProperties">
            <props>
                <!--命名策略-->
                <prop key="hibernate.ejb.naming_strategy">org.hibernate.cfg.ImprovedNamingStrategy</prop>

                <!--基本配置-->
                <prop key="hibernate.format_sql">true</prop>
                <prop key="hibernate.show_sql">true</prop>
                <prop key="hibernate.hbm2ddl.auto">update</prop>
                <prop key="hibernate.dialect">org.hibernate.dialect.MySQL5InnoDBDialect</prop>

                <!--使用JPA的二级缓存-->
                <prop key="hibernate.cache.use_second_level_cache">true</prop>
                <prop key="hibernate.cache.region.factory_class">org.hibernate.cache.ehcache.EhCacheRegionFactory</prop>
                <prop key="hibernate.cache.use_query_cache">true</prop>
            </props>
        </property>
        <property name="sharedCacheMode" value="ENABLE_SELECTIVE"/>
    </bean>

（3）在实体类上添加缓存功能

 

 

package com.hongtu.entity;

import org.hibernate.annotations.Cache;
import org.hibernate.annotations.CacheConcurrencyStrategy;

import javax.persistence.*;
import java.io.Serializable;

/**
 *  用户实体类
 *
 * @author LIUTAO
 * @version 2017/5/11
 * @see
 * @since
 */
@Cache(usage = CacheConcurrencyStrategy.READ_ONLY)
@Cacheable(true)
@Entity
public class User implements Serializable {
    private static final long serialVersionUID = -8081225022334946487L;
    private String name;            //用户名
    private Integer age;            //年龄
    private String password;        //用户密码
    private int id;                 //用户Id

    public User() {
    }

    public User(String name, Integer age, String password, int id) {
        this.name = name;
        this.age = age;
        this.password = password;
        this.id = id;
    }

    @Basic
    @Column(name = "name")
    public String getName() {
        return name;
    }

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

    @Basic
    @Column(name = "age")
    public Integer getAge() {
        return age;
    }

    public void setAge(Integer age) {
        this.age = age;
    }

    @Basic
    @Column(name = "password")
    public String getPassword() {
        return password;
    }

    public void setPassword(String password) {
        this.password = password;
    }

    @Id
    @Column(name = "id")
    public int getId() {
        return id;
    }

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

    @Override
    public boolean equals(Object o) {
        if (this == o) return true;
        if (o == null || getClass() != o.getClass()) return false;

        User user = (User) o;

        if (id != user.id) return false;
        if (name != null ? !name.equals(user.name) : user.name != null) return false;
        if (age != null ? !age.equals(user.age) : user.age != null) return false;
        if (password != null ? !password.equals(user.password) : user.password != null) return false;

        return true;
    }

    @Override
    public int hashCode() {
        int result = name != null ? name.hashCode() : 0;
        result = 31 * result + (age != null ? age.hashCode() : 0);
        result = 31 * result + (password != null ? password.hashCode() : 0);
        result = 31 * result + id;
        return result;
    }

    @Override
    public String toString() {
        return "User{" +
                "name='" + name + '\'' +
                ", age=" + age +
                ", password='" + password + '\'' +
                ", id=" + id +
                '}';
    }
}

（4）在dao上使用缓存

 

 

package com.hongtu.dao;

import com.hongtu.entity.User;
import org.springframework.data.jpa.repository.JpaRepository;
import org.springframework.data.jpa.repository.QueryHints;

import javax.persistence.QueryHint;
import java.util.List;

/**
 * 用户jpa持久层
 *
 * @author LIUTAO
 * @version 2017/5/11
 * @see
 * @since
 */
public interface UserDao extends JpaRepository<User,Integer> {

    /**
     * 获取用户
     * @param id
     * @return
     */
    @QueryHints({ @QueryHint(name = "org.hibernate.cacheable", value ="true") })
    User findUserById(int id);
}

（5）进行单元测试

 

 

@Test
    public void testFindUserByIdOfJpa(){
        logger.debug("this user was found by jpa is "+userDao.findUserById(1));
        logger.debug("this user was found by jpa is "+userDao.findUserById(1));
    }

 

以下是运行结果：

2017-05-12 15:45:32.381 [main] DEBUG org.mybatis.spring.SqlSessionFactoryBean - Parsed mapper file: 'file [E:\MySelf\SpringDemo_hongtu_01\target\classes\mapper\UserMapper.xml]'
Hibernate: 
    select
        user0_.id as id1_0_,
        user0_.age as age2_0_,
        user0_.name as name3_0_,
        user0_.password as password4_0_ 
    from
        User user0_ 
    where
        user0_.id=?
2017-05-12 15:45:34.036 [main] DEBUG com.hongtu.test.TestUser - this user was found by jpa is User{name='张三丰', age=45, password='zsf123', id=1}
2017-05-12 15:45:34.040 [main] DEBUG com.hongtu.test.TestUser - this user was found by jpa is User{name='张三丰', age=45, password='zsf123', id=1}
Process finished with exit code 0

从上面的运行结果可以看出，进行了两次查询，但是最终仅仅和数据库进行了一次数据交互。

项目代码参考gitHub地址：jpa二级缓存使用