MyBatis二级缓存开启之后并没有效果，求助。

2017-08-04 03:02:44 779 阅读 AI 写同款 · GEO 优化AI 选题数据监测一键分发 ›

Springboot 集成 mybatis 开启二级缓存（redis）首先来了解下mybatis 缓存，mybatis缓存分为一级缓存和二级缓存。一级缓存是默认开启的，无需其他配置操作，二级缓存则需要手动设置开启。一级缓存原理： Mybatis的一级缓存是指同一个SqlSession中的操作。一级缓存的作用域是一个SqlSession。在同一个SqlSession中，执行相同的查询SQL，第一次会去查询数据库，并写到缓存中；第二次直接从缓存中取。当执行SQL时... 阅读详情

config.xml已开启
<setting name="cacheEnabled" value="true"/>

mapper.xml 已开启
<cache ></cache>

select语句
<select id="getById" resultType="User" useCache="true">
select * from m_user where id=#{id}
</select>

测试语句
public void testTwo() {
int begin,end;
SqlSession session1=SessionHelper.getSession();
UserMapper uMapper1=session1.getMapper(UserMapper.class);
begin=(int) System.currentTimeMillis();
User user1=uMapper1.getById(1);
end=(int) System.currentTimeMillis();
int x1=end-begin;
System.out.println("------------>"+user1.toString());
session1.close();

SqlSession session2=SessionHelper.getSession();
UserMapper uMapper2=session2.getMapper(UserMapper.class);
begin=(int) System.currentTimeMillis();
User user2=uMapper2.getById(1);
int x2=begin-end;
System.out.println("------------>"+user2.toString());
System.out.println(x1+"间隔事件对比"+x2);
session2.close();
}

log输出

DEBUG - Openning JDBC Connection
DEBUG - Created connection 31209237.
DEBUG - ooo Using Connection [com.mysql.cj.jdbc.ConnectionImpl@1dc3715]
DEBUG - ==> Preparing: select * from m_user where id=?
DEBUG - ==> Parameters: 1(Integer)
------------>id:1 username:update password:test
DEBUG - Resetting autocommit to true on JDBC Connection [com.mysql.cj.jdbc.ConnectionImpl@1dc3715]
DEBUG - Closing JDBC Connection [com.mysql.cj.jdbc.ConnectionImpl@1dc3715]
DEBUG - Returned connection 31209237 to pool.
DEBUG - Find JAR URL: file:/E:/EclipseEEWorkspace/MyBatisPractice1/bin/com/clei/domain
DEBUG - Not a JAR: file:/E:/EclipseEEWorkspace/MyBatisPractice1/bin/com/clei/domain
DEBUG - Reader entry: Course.class
DEBUG - Reader entry: Husband.class
DEBUG - Reader entry: Student.class
DEBUG - Reader entry: User.class
DEBUG - Reader entry: Wife.class
DEBUG - Listing file:/E:/EclipseEEWorkspace/MyBatisPractice1/bin/com/clei/domain
DEBUG - Find JAR URL: file:/E:/EclipseEEWorkspace/MyBatisPractice1/bin/com/clei/domain/Course.class
DEBUG - Cache Hit Ratio [com.clei.mapper.UserMapper]: 0.0
这还有一大段没复制过来。
DEBUG - Openning JDBC Connection
DEBUG - Created connection 19037581.
DEBUG - ooo Using Connection [com.mysql.cj.jdbc.ConnectionImpl@1227d8d]
DEBUG - ==> Preparing: select * from m_user where id=?
DEBUG - ==> Parameters: 1(Integer)
------------>id:1 username:update password:test
390间隔事件对比78
DEBUG - Resetting autocommit to true on JDBC Connection [com.mysql.cj.jdbc.ConnectionImpl@1227d8d]
DEBUG - Closing JDBC Connection [com.mysql.cj.jdbc.ConnectionImpl@1227d8d]
DEBUG - Returned connection 19037581 to pool.

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