mybatis实例(mybatis使用详解)

Caching Executor的作用就是实现二级缓存，使用的是装饰者模式。

装饰者模式：在不改变原有类继承结构的情况下，新建一个对象来扩展原有功能。

maven依赖

     org.mybatis 
     mybatis 
     3.5.7 


    mysql
    mysql-connector-java
    8.0.20

public interface UserMapper {

    @Select("select name from user where id = #{id}")
    String selectById(@Param("id") int id);

    @Update("update user set name=#{arg1} where id=#{arg0}")
    void updateById(int id,String name);
}

public class ExecutorTest {

    private Configuration configuration;

    private Connection connection;

    private JdbcTransaction jdbcTransaction;

    private  MappedStatement ms;

    @Before
    public void init() throws Exception {
        InputStream in = Resources.getResourceAsStream("mybatis-config.xml");
        SqlSessionFactoryBuilder builder = new SqlSessionFactoryBuilder();
        SqlSessionFactory factory = builder.build(in);
        configuration = factory.getConfiguration();
        connection = DriverManager.getConnection(JDBC.URL,JDBC.USERNAME,JDBC.PASSWORD);
        jdbcTransaction = new JdbcTransaction(connection);
        ms = configuration.getMappedStatement("dao.UserMapper.selectById");
    }

    
    @Test
    public void simpleTest() throws Exception {
        SimpleExecutor executor = new SimpleExecutor(configuration,jdbcTransaction);

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