MyBatis 入门

 

每个MyBatis的中心是SqlSessionFactory，SqlSessionFactory可以使用XML来配置，使用XML的配置文件如下：

 

inputStream = Resources.getResourceAsStream("mybatis-config.xml");
SqlSessionFactory sqlSessionFactory = new SqlSessionFactoryBuilder().build(inputStream);

 

XML的配置文件，简单的示例如下：

 

<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE configuration
  PUBLIC "-//mybatis.org//DTD Config 3.0//EN"
  "http://mybatis.org/dtd/mybatis-3-config.dtd">
<configuration>
  <environments default="development">
    <environment id="development">
      <transactionManager type="JDBC"/>
      <dataSource type="POOLED">
        <property name="driver" value="${driver}"/>
        <property name="url" value="${url}"/>
        <property name="username" value="${username}"/>
        <property name="password" value="${password}"/>
      </dataSource>
    </environment>
  </environments>
  <mappers>
    <mapper resource="org/mybatis/example/BlogMapper.xml"/>
  </mappers>
</configuration>

 

不使用XML配置文件也可以这样写：

 

DataSource dataSource = new TestDataSource();
		TransactionFactory transactionFactory = new JdbcTransactionFactory();
		Environment environment = new Environment("development", transactionFactory, dataSource);
		Configuration configuration = new Configuration(environment);
		configuration.addMapper(BlogMapper.class);
		SqlSessionFactory sqlSessionFactory = new SqlSessionFactoryBuilder().build(configuration);

 

你可以用这样的语句来查询数据库

 

SqlSession session = sqlSessionFactory.openSession();
try {
  Blog blog = session.selectOne("org.mybatis.example.BlogMapper.selectBlog", 101);
} finally {
  session.close();
}

 

也可以使用：

 

SqlSession session = sqlSessionFactory.openSession();
try {
  BlogMapper mapper = session.getMapper(BlogMapper.class);
  Blog blog = mapper.selectBlog(101);
} finally {
  session.close();
}