myBatis系列之一：搭建开发环境

myBatis系列之二：以接口方式交互数据
myBatis系列之三：增删改查
myBatis系列之四：关联数据的查询
myBatis系列之五：与Spring3集成
myBatis系列之六：与SpringMVC集成
myBatis系列之七：事务管理


1. pom.xml文件中加入mybatis和数据库依赖，这里使用mysql：

  <properties>
    <mybatis.version>3.2.3</mybatis.version>
    <mysql.version>5.1.26</mysql.version>
    <slf4j.api.version>1.7.5</slf4j.api.version>
    <testng.version>6.8.7</testng.version>
  </properties>

  <dependencies>
    <dependency>
      <groupId>org.mybatis</groupId>
      <artifactId>mybatis</artifactId>
      <version>${mybatis.version}</version>
    </dependency>
    <!-- Database driver -->
    <dependency>
      <groupId>mysql</groupId>
      <artifactId>mysql-connector-java</artifactId>
      <version>${mysql.version}</version>
    </dependency>
    <!-- mybatis启动要加载log4j -->
    <dependency>
      <groupId>org.slf4j</groupId>
      <artifactId>slf4j-log4j12</artifactId>
      <version>${slf4j.api.version}</version>
    </dependency>
    <!-- Test -->
    <dependency>
      <groupId>org.testng</groupId>
      <artifactId>testng</artifactId>
      <version>${testng.version}</version>
    </dependency>
  </dependencies>

2. 在类路径下创建mybatis的配置文件Configuration.xml

<?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>
	<typeAliases><!-- 别名 -->
		<typeAlias alias="User" type="com.john.hbatis.model.User" />
	</typeAliases>
	
	<environments default="development">
	  <environment id="development">
		<transactionManager type="JDBC"/>
		<dataSource type="POOLED"><!-- 数据源 -->
			<property name="driver" value="com.mysql.jdbc.Driver" />
			<property name="url" value="jdbc:mysql://localhost:3306/hbatis" />
			<property name="username" value="root" />
			<property name="password" value="123456" />
		</dataSource>
	  </environment>
	</environments>
	
	<mappers><!-- ORM映射文件 -->
		<mapper resource="com/john/hbatis/model/User.xml" />
	</mappers>
 </configuration>

3. 执行创建数据库和表的sql：

-- Create the database named 'hbatis'.
-- It's OK to use `, not OK to use ' or " surrounding the database name to prevent it from being interpreted as a keyword if possible.
CREATE DATABASE IF NOT EXISTS `hbatis`
DEFAULT CHARACTER SET = `UTF8`;

-- Create a table named 'User'
CREATE TABLE `user` (
	`id` int(11) NOT NULL AUTO_INCREMENT,
	`name` varchar(50) DEFAULT NULL,
	`age` int(11) DEFAULT NULL,
	`address` varchar(200) DEFAULT NULL,
	PRIMARY KEY (`id`)
) ENGINE=InnoDB AUTO_INCREMENT=2 DEFAULT CHARSET=utf8;

-- Insert a test record
Insert INTO `user` VALUES ('1', 'john', '120', 'hangzhou,westlake');

4. com.john.hbatis.model.User类：

public class User {
    private int id;
    private String name;
    private String age;
    private String address;
    // Getters and setters are omitted

    // 如果有带参数的构造器，编译器不会自动生成无参构造器。当查询需要返回对象时，ORM框架用反射来调用对象的无参构造函数，导致异常：java.lang.NoSuchMethodException: com.john.hbatis.model.User.<init>()
    // 这时需要明确写出：
    public User() {
    }

    public User(int id, String address) {
        this.id = id;
        this.address = address;
    }

    public User(String name, int age, String address) {
        this.name = name;
        this.age = age;
        this.address = address;
    }
}

com/john/hbatis/model路径下的User.xml

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE mapper PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN" "http://mybatis.org/dtd/mybatis-3-mapper.dtd">
<mapper namespace="com.john.hbatis.model.UserMapper">
	<select id="getUserById" parameterType="int" resultType="User">
		select * from `user` where id = #{id}
	</select>
</mapper>

5. 测试类：

public class MyBatisBasicTest {
	private static final Logger log = LoggerFactory.getLogger(MyBatisBasicTest.class);
	private static SqlSessionFactory sqlSessionFactory;
	
	private static Reader reader;
	
	@BeforeClass
	public static void initial() {
		try {
			reader = Resources.getResourceAsReader("Configuration.xml");
			sqlSessionFactory = new SqlSessionFactoryBuilder().build(reader);
		} catch (IOException e) {
			log.error("Error thrown while reading the configuration: {}", e);
		} finally {
			if (reader != null) {
				try {
					reader.close();
				} catch (IOException e) {
					log.error("Error thrown while closing the reader: {}", e);
				}
			}
		}
	}
	
	@Test
	public void queryTest() {
		SqlSession session = sqlSessionFactory.openSession();
		User user = (User)session.selectOne("com.john.hbatis.model.UserMapper.getUserById", 1);
		log.info("{}: {}", user.getName(), user.getAddress());
	}
}

参考：
http://www.yihaomen.com/article/java/303.htm