以前的iBatis 项目在2010 年5 月，将代码库迁致Google Code，并更名为MyBatis。
本示例用的是ibatis-3-core-3.0.0.208.zip，首先加如mybatis和mysql数据库的jar包。
table.sql
create database mybatis; use mybatis; create table user( id int primary key auto_increment, name varchar(50) ); insert into user values(null,'张三');
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> <typeAlias alias="User" type="com.nantian.mybatis.model.User"/> </typeAliases> <environments default="development"> <environment id="development"> <transactionManager type="JDBC"/> <dataSource type="POOLED"> <property name="driver" value="com.mysql.jdbc.Driver"/> <property name="url" value="jdbc:mysql://127.0.0.1:3306/mybatis"/> <property name="username" value="root"/> <property name="password" value="root"/> </dataSource> </environment> </environments> <mappers> <mapper resource="com/nantian/mybatis/model/UserMapper.xml"/> </mappers> </configuration>
DBUtil
package com.nantian.mybatis.data; import java.io.IOException; import java.io.Reader; import org.apache.ibatis.io.Resources; import org.apache.ibatis.session.SqlSessionFactory; import org.apache.ibatis.session.SqlSessionFactoryBuilder; public class DBUtil { private static final DBUtil dbUtil = new DBUtil(); private SqlSessionFactory sqlSessionFactory = null; private DBUtil() { try { String resource = "com/nantian/mybatis/data/configuration.xml"; Reader reader = Resources.getResourceAsReader(resource); sqlSessionFactory = new SqlSessionFactoryBuilder().build(reader); reader.close(); } catch (IOException e) { e.printStackTrace(); } } public static DBUtil getInstance() { return dbUtil; } public SqlSessionFactory getSqlSessionFactory() { return sqlSessionFactory; } }
User
package com.nantian.mybatis.model; public class User { private int id; private String name; public int getId() { return id; } public void setId(int id) { this.id = id; } public String getName() { return name; } public void setName(String name) { this.name = name; } }
UserMapper
package com.nantian.mybatis.model; public interface UserMapper { public User selectUser(int id); }
UserMapper.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.nantian.mybatis.model.UserMapper"> <select id="selectUser" parameterType="int" resultType="User"> select id,name from user where id = #{id} </select> </mapper>
Test
package com.nantian.mybatis.test; import junit.framework.TestCase; import org.apache.ibatis.session.SqlSession; import com.nantian.mybatis.data.DBUtil; import com.nantian.mybatis.model.User; import com.nantian.mybatis.model.UserMapper; public class Test extends TestCase { public void selectUser() { SqlSession sqlSession = DBUtil.getInstance().getSqlSessionFactory() .openSession(); try { UserMapper userMapper = sqlSession.getMapper(UserMapper.class); User user = userMapper.selectUser(1); System.out.println(user.getName()); } finally { sqlSession.close(); } } }
Mybatis3可以使用注解了。注解是非常简单明了的，但是JAVA 注解既有局限性，在语句比较复杂的情况下又比较容易混乱。所以，如果你的语句比较复杂，最好还是使用XML 来映射语句。这主要取决于你和你的项目团队，决定哪个更适合于你，主要还是以稳健为主。也就是说，你不需要制约于哪一种方式，你可以很容易的把注解转为XML，也可以把XML 转化为注解。
