Mybatis level 1 cache: In the same sqlsession, the query statement is the same and the query parameters are the same, and the cached data is fetched in the second query
import org.apache.ibatis.session.SqlSession;
import org.apache.ibatis.session.SqlSessionFactory;
import org.apache.ibatis.session.defaults.DefaultSqlSessionFactory;
import org.mybatis.spring.SqlSessionFactoryBean;
import org.springframework.context.support.ClassPathXmlApplicationContext;
import cn.mgr.user.po.UserPO;
//mybatis first level cache
public class SessionTest {
public static void main(String[] args)throws Exception{
ClassPathXmlApplicationContext app = new ClassPathXmlApplicationContext("applicationContext.xml");
DefaultSqlSessionFactory factory = (DefaultSqlSessionFactory)app.getBean("sqlSessionFactory");
mybatisFirstCache(factory); //Level 1 Cache: must be in the same session
//mybatisFirstCache2(factory);
//mybatisFirstCache3(factory);
}
/**
* mybatis first-level cache: sql in the same session will be cached:
* the query statement is the same and the query parameters are the same, The second time to get the cached result in the same session
* @param factory
*/
static void mybatisFirstCache(DefaultSqlSessionFactory factory){
SqlSession session = factory.openSession();
String statement = "cn.mgr.user.mapper.UserMapper.findByID ";
UserPO user = new UserPO();
user.setUserId(100);
UserPO u = session.selectOne(statement, user);
System.out.println("First query: "+u.getUserName());
user = new UserPO();
user.setUserId(100);
u = session.selectOne(statement, user);
System.out.println("Second query: "+u.getUserName());
session.close();
}
/**
* mybatis first level cache: sql in the same session will be cached:
* the query statement is the same and the query parameters are different, the database will still be queried for the second time
* @param factory
*/
static void mybatisFirstCache2(DefaultSqlSessionFactory factory){
SqlSession session = factory.openSession();
String statement = "cn.mgr.user.mapper.UserMapper.findByID";
UserPO user = new UserPO();
user.setUserId(100);
UserPO u = session.selectOne(statement, user);
System.out.println("First query: "+u.getUserName());
user = new UserPO();
user.setUserId (101);
u = session.selectOne(statement, user);
System.out.println("Second query: "+u.getUserName());
session.close();
}
/**
* mybatis level 1 Cache: Different sessions
* with the same query statement and different query parameters, will still query the database for the second time
* @param factory
*/
static void mybatisFirstCache3(DefaultSqlSessionFactory factory){
SqlSession session = factory.openSession();
String statement = "cn. mgr.user.mapper.UserMapper.findByID";
UserPO user = new UserPO();
user.setUserId(100);
UserPO u = session.selectOne(statement, user);
System.out.println("第一次查询："+u.getUserName());
session.close();
session = factory.openSession();
user = new UserPO();
user.setUserId(100);
u = session.selectOne(statement, user);
System.out.println("第二次查询："+u.getUserName());
session.close();
}
}