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Mybatis 学习
1. Mybatis的重要的配置文件 mybatis-config.xml 和 实体类的配置文件
mybatis-config.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> <properties resource="jdbc.properties"/> <typeAliases> <package name="andy.com.model"/> </typeAliases> <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> <!-- 将mapper文件加入到配置文件中 --> <mappers> <mapper class="andy.com.mapper.UserMapper"/> </mappers> </configuration>
2. 实体类配置文件 User.xml , 对sql的映射,该实体类的配置文件一般和实体类放在一起,
<?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="andy.com.model.User"> <!-- <mapper namespace="andy.com.mapper.UserMapper"> --> 这个是另外一只方式,需要建一个UserMapper的接口 <insert id="add" parameterType="User"> insert into users (username,password,nickname,type) value(#{username},#{password},#{nickname},#{type}) </insert> <update id="update" parameterType="User"> update users set password=#{password},nickname=#{nickname},type=#{type} where id=#{id} </update> <delete id="delete" parameterType="int"> delete from users where id=#{id} </delete> <select id="load" parameterType="int" resultType="User"> select * from users where id=#{id} </select> <select id="list" resultType="User"> select * from users </select> </mapper>
3. Mybatsi util 公共类, 完成对session的获取
package andy.com.util; import java.io.IOException; import java.io.InputStream; import org.apache.ibatis.io.Resources; import org.apache.ibatis.session.SqlSession; import org.apache.ibatis.session.SqlSessionFactory; import org.apache.ibatis.session.SqlSessionFactoryBuilder; public class MyBatisUtil { private static SqlSessionFactory factory; static { try { InputStream is = Resources.getResourceAsStream("mybatis-config.xml"); factory = new SqlSessionFactoryBuilder().build(is); } catch (IOException e) { e.printStackTrace(); } } public static SqlSession createSession() { return factory.openSession(); } public static void closeSession(SqlSession session) { if(session!=null) session.close(); } }
4. 测试Mybatis
package andy.com.test; import andy.com.model.User; import andy.com.util.MyBatisUtil; import java.io.IOException; import java.io.InputStream; import java.util.List; import org.apache.ibatis.io.Resources; import org.apache.ibatis.session.SqlSession; import org.apache.ibatis.session.SqlSessionFactory; import org.apache.ibatis.session.SqlSessionFactoryBuilder; import org.junit.Test; public class TestMyBatis { @Test public void testDelete() { try { InputStream is = Resources.getResourceAsStream("mybatis-config.xml"); SqlSessionFactory f = new SqlSessionFactoryBuilder().build(is); SqlSession session = f.openSession(); session.delete(User.class.getName()+".delete",1); session.commit(); session.close(); } catch (IOException e) { e.printStackTrace(); } } @Test public void testAdd() { SqlSession session = null; try { session = MyBatisUtil.createSession(); User u = new User(); u.setNickname("andy"); u.setPassword("password"); u.setType(1); u.setUsername("dawang"); session.insert(User.class.getName()+".add", u); session.commit(); } catch (Exception e) { e.printStackTrace(); session.rollback(); } finally { MyBatisUtil.closeSession(session); } } @Test public void testLoad() { SqlSession session = null; try{ session = MyBatisUtil.createSession(); User u = (User)session.selectOne(User.class.getName()+".load", 1); System.out.println(u.getNickname()); } finally { MyBatisUtil.closeSession(session); } } @Test public void testList() { SqlSession session = null; try{ session = MyBatisUtil.createSession(); List<User> us = session.selectList(User.class.getName()+".list", null); System.out.println(us.size()); } finally { MyBatisUtil.closeSession(session); } } }
Mybatis 学习
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