Reader reader = Resources.getResourceAsReader("config/configuration.xml");
        //創(chuàng)建數(shù)據(jù)工廠
        SqlSessionFactoryBuilder builder = new SqlSessionFactoryBuilder();
        SqlSessionFactory sqlSessionFactory = builder.build(reader);
        SqlSession sqlSession = sqlSessionFactory.openSession(true);
 
         // 。。。。。。 
        // 這中間所走的所有查詢(xún)操作都會(huì)進(jìn)行緩存，一旦關(guān)閉sqlSession會(huì)話(huà)，緩存則會(huì)刷新
 
        //釋放會(huì)話(huà)
        sqlSession.clearCache();
        // 關(guān)閉會(huì)話(huà)
        sqlSession.close();

<settings>
        <!--標(biāo)準(zhǔn)的日志工廠實(shí)現(xiàn)類(lèi)，打印sql日志-->
        <setting name="logImpl" value="STDOUT_LOGGING"/>
    </settings>

public static void main(String[] args) throws IOException {
 
        // 加載mybatis配置文件
        Reader reader = Resources.getResourceAsReader("config/configuration.xml");
        //創(chuàng)建數(shù)據(jù)工廠
        SqlSessionFactoryBuilder builder = new SqlSessionFactoryBuilder();
        SqlSessionFactory sqlSessionFactory = builder.build(reader);
        SqlSession sqlSession = sqlSessionFactory.openSession(true);
 
 
        // 獲取mapper接口對(duì)象
        UserMapper mapper = sqlSession.getMapper(UserMapper.class);
 
        // 查詢(xún)第一次
        User user = mapper.selectByPrimaryKey("3rfrf34r34");
        // 第二次查詢(xún)
        User user1 = mapper.selectByPrimaryKey("3rfrf34r34");
        System.out.println("兩個(gè)user對(duì)象是否相等："+(user == user1));
        //釋放會(huì)話(huà)
        sqlSession.clearCache();
        sqlSession.close();
    }

public static void main(String[] args) throws IOException {
 
        // 加載mybatis配置文件
        Reader reader = Resources.getResourceAsReader("config/configuration.xml");
        //創(chuàng)建數(shù)據(jù)工廠
        SqlSessionFactoryBuilder builder = new SqlSessionFactoryBuilder();
        SqlSessionFactory sqlSessionFactory = builder.build(reader);
        SqlSession sqlSession = sqlSessionFactory.openSession(true);
 
 
        // 獲取mapper接口對(duì)象
        UserMapper mapper = sqlSession.getMapper(UserMapper.class);
        // 查詢(xún)第一次
        User user = mapper.selectByPrimaryKey("3rfrf34r34");
        
        // 修改
        mapper.updateByPrimaryKey(user);
        // 第二次查詢(xún)
        User user1 = mapper.selectByPrimaryKey("3rfrf34r34");
        System.out.println("兩個(gè)user對(duì)象是否相等："+(user == user1));
        //釋放會(huì)話(huà)
        sqlSession.clearCache();
        sqlSession.close();
    }

 <!-- 開(kāi)啟單個(gè)mapper的二級(jí)緩存，也叫全局緩存-->
  <cache />

 <settings>
        <!--  開(kāi)啟所有mapper的二級(jí)緩存 -->
        <!--<setting name="cacheEnabled" value="true" />-->
    </settings>

 public static void main(String[] args) throws IOException {
 
        // 加載mybatis配置文件
        Reader reader = Resources.getResourceAsReader("config/configuration.xml");
        //創(chuàng)建數(shù)據(jù)工廠
        SqlSessionFactoryBuilder builder = new SqlSessionFactoryBuilder();
 
        SqlSessionFactory sqlSessionFactory = builder.build(reader);
 
        // 第一個(gè)會(huì)話(huà)
        SqlSession sqlSession = sqlSessionFactory.openSession(true);
 
 
        // 獲取會(huì)話(huà)一的mapper接口對(duì)象
        UserMapper mapper = sqlSession.getMapper(UserMapper.class);
 
        // 第一次查詢(xún)
        User user = mapper.selectByPrimaryKey("3rfrf34r34");
        
        //釋放第一個(gè)會(huì)話(huà)
        sqlSession.clearCache();
        sqlSession.close();
        // 第二個(gè)會(huì)話(huà)
        SqlSession sqlSession2 = sqlSessionFactory.openSession(true);
        // 獲取會(huì)話(huà)二的mapper接口對(duì)象
        UserMapper mapper2 = sqlSession2.getMapper(UserMapper.class);
        // 第二次查詢(xún)
        User user1 = mapper2.selectByPrimaryKey("3rfrf34r34");
        // 釋放第二個(gè)會(huì)話(huà)
        sqlSession2.clearCache();
        sqlSession2.close();
    }