mybatis 基本
今天刚听说iBATIS改名为MyBatis,实际上就是iBATIS 3.0.1。以前都是用hibernate或者JPA,同时听说iBATIS 3与iBATIS 2 相比,变化挺大的,于是今天花了点时间学习了一下,做了个小例子。
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准备工作:建立相应的数据库,表,添加一条记录用于测试。
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第一步当然是建立项目,导入jar包,导入mybatis-3.0.1.jar,和mysql的jdbc驱动。
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第二步 新建一个类User,包含主键,用户名,密码等属性
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- package cn.dcr.mybatis.entity;public class User {private Long id;private String userName;private String password;private int age;public Long getId() {return id;}public void setId(Long id) {this.id = id;}public String getUserName() {return userName;}public void setUserName(String userName) {this.userName = userName;}public String getPassword() {return password;}public void setPassword(String password) {this.password = password;}public int getAge() {return age;}public void setAge(int age) {this.age = age;}}
?第三步,写sql映射的xml文件
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- <?xml version="1.0" encoding="UTF-8" ?> <!DOCTYPE mapper PUBLIC "-//ibatis.apache.org//DTD Mapper 3.0//EN" "http://ibatis.apache.org/dtd/ibatis-3-mapper.dtd"> <mapper namespace="cn.dcr.mybatis.entity.UserMapper"> <select id="selectOne" parameterType="long" resultType="cn.dcr.mybatis.entity.User"> select * from user where id = #{id} </select> </mapper>
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?第四步,写MyBatis配置文件,configuration.xml
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- <?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="com.mysql.jdbc.Driver"/> <property name="url" value="jdbc:mysql://localhost:3306/test"/> <property name="username" value="root"/> <property name="password" value="root"/> </dataSource> </environment> </environments> <mappers> <mapper resource="cn/dcr/mybatis/entity/User.xml"/> </mappers></configuration>
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第五步,编写Util类,用于初始化SqlSessionFactory
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- package cn.dcr.mybatis.util;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 Util {private static SqlSessionFactory sqlSessionFactory = null;static {String resource = "configuration.xml"; Reader reader = null;try {reader = Resources.getResourceAsReader(resource);} catch (IOException e) {e.printStackTrace();}sqlSessionFactory = new SqlSessionFactoryBuilder().build(reader);}public static SqlSessionFactory getSqlSessionFactory(){return sqlSessionFactory;}}
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第六步,编写Dao类,用于封装增删改查等操作(为简单起见,这个类只有一个根据id查询出对应的User对象的方法)
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- package cn.dcr.mybatis.dao;import org.apache.ibatis.session.SqlSession;import cn.dcr.mybatis.entity.User;import cn.dcr.mybatis.util.Util;public class UserDao {public User query(Long id){SqlSession session = Util.getSqlSessionFactory().openSession();User user = null;try{ user = (User)session.selectOne("cn.dcr.mybatis.entity.UserMapper.selectOne", id);}catch(Exception e){e.printStackTrace();}finally{session.close();}return user;}}
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第七步,编写测试类
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- package cn.dcr.mybatis.test;import cn.dcr.mybatis.dao.UserDao;import cn.dcr.mybatis.entity.User;public class UserTest {public static void main(String[] args){UserDao userDao = new UserDao();User user = userDao.query(1L);System.out.println(user.getId());System.out.println(user.getUserName());System.out.println(user.getPassword());System.out.println(user.getAge());}}
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运行一下,能够成功查询出对应的记录。
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先到这,等有功夫在研究一下详细用法。
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比较详细了,不上传源码了。
1 楼 log4j_properties 2011-12-21 多贴了一个pojo,少贴一个mapper吧?