mybatis缓存之二级缓存

<setting name="lazyLoadingEnabled" value="true"/>

<mapper namespace="com.gong.mybatis.dao.EmployeeMapper">
    <cache eviction="FIFO" flushInterval="60000" readOnly="false" size="1024">
        <!-- 
            eviction：缓存的回收策略，默认LRU
            flushInterval：缓存刷新间隔，默认不清空，可以设置一个毫秒值
            readOnly：只读为true，所有从缓存中获取操作都是只读操作，不会修改数据，直接将数据在缓存中的引用交给用户；
                     非只读，获取的数据可能会被修改，会利用序列化&反序列化的技术克隆一份新的数据，安全，但速度慢。
            size：缓存存放多少元素
            type：指定自定义缓存的全类名，实现Cache接口即可
         -->
    </cache>

    ......
</mapper>

public class Employee implements Serializable

package com.gong.mybatis.test;

import java.io.IOException;
import java.io.InputStream;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.HashMap;
import java.util.List;
import java.util.Map;

import org.apache.ibatis.io.Resources;
import org.apache.ibatis.session.SqlSession;
import org.apache.ibatis.session.SqlSessionFactory;
import org.apache.ibatis.session.SqlSessionFactoryBuilder;
import org.junit.Test;

import com.gong.mybatis.bean.Department;
import com.gong.mybatis.bean.Employee;
import com.gong.mybatis.dao.EmployeeMapper;
import com.gong.mybatis.mapper.EmployeeMapperDynamicSql;

public class TestMybatis4 {
    
    public SqlSessionFactory getSqlSessionFactory() throws IOException {
        String resource = "mybatis-config.xml";
        InputStream is = Resources.getResourceAsStream(resource);
        return new SqlSessionFactoryBuilder().build(is);
    }

    @Test
    public void test() throws IOException {
        SqlSessionFactory sqlSessionFactory = getSqlSessionFactory();
        SqlSession openSession = sqlSessionFactory.openSession();
        SqlSession openSession2 = sqlSessionFactory.openSession();
        
        try {
            EmployeeMapper mapper = openSession.getMapper(EmployeeMapper.class);
            EmployeeMapper mapper2 = openSession2.getMapper(EmployeeMapper.class);
            Employee em = mapper.getEmpById(1);
            System.out.println(em);
            openSession.close();
            Employee em2 = mapper2.getEmpById(1);
            System.out.println(em2);
            openSession.close();
        } finally {
            // TODO: handle finally clause
            
        }
            
    }
    
}

DEBUG 01-22 10:59:28,726 Cache Hit Ratio [com.gong.mybatis.dao.EmployeeMapper]: 0.0  (LoggingCache.java:62) 
DEBUG 01-22 10:59:29,055 ==>  Preparing: select id,last_name lastName,email,gender from tbl_employee where id = ?   (BaseJdbcLogger.java:145) 
DEBUG 01-22 10:59:29,102 ==> Parameters: 1(Integer)  (BaseJdbcLogger.java:145) 
DEBUG 01-22 10:59:29,148 <==      Total: 1  (BaseJdbcLogger.java:145) 
Employee [id=1, lastName=dema, gender=1, email=dema@qq.com, dept=null]
DEBUG 01-22 10:59:29,242 Cache Hit Ratio [com.gong.mybatis.dao.EmployeeMapper]: 0.5  (LoggingCache.java:62) 
Employee [id=1, lastName=dema, gender=1, email=dema@qq.com, dept=null]