Mybatis简单入门
- 一、创建项目导入相应的jar包（数据库驱动包和mybatis jar包）
二、在src目录下，建立conf.xml配置文件
<?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">
//127.0.0.1:3306/student?characterEncoding=utf-8" />
三、根据数据表字段建立实体类，需要一一对应关系
package com.pojo;
public class User {
private int userId;private String userName;private String passWord;public int getUserId() {return userId;}public void setUserId(int userId) {this.userId = userId;}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;}@Overridepublic String toString() {return "User [userId=" + userId + ", userName=" + userName + ", passWord=" + passWord + "]";}
}
四、建立操作映射文件
<?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">
五、建立操作接口
package com.dao;
import com.pojo.User;public interface IUserDao {
public User getUserById(int userId);
}六、dao类
package com.dao;
import java.io.FileNotFoundException;
import java.io.IOException;
import java.io.InputStream;
import java.io.Reader;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 MyBatisBaseDao {
public static SqlSessionFactory sqlSessionFactory;public static SqlSessionFactoryBuilder sqlSessionFactoryBuilder;public static SqlSession session;// mybatis的配置文件public static String resource = "conf.xml";static {// 使用类加载器加载mybatis的配置文件（它也加载关联的映射文件）InputStream is = UserDao.class.getClassLoader().getResourceAsStream(resource);try {// 构建sqlSession的工厂// SqlSessionFactory sessionFactory = new// SqlSessionFactoryBuilder().build(is);// 使用MyBatis提供的Resources类加载mybatis的配置文件（它也加载关联的映射文件）Reader reader = Resources.getResourceAsReader(resource);// 构建sqlSession的工厂SqlSessionFactory sessionFactory = new SqlSessionFactoryBuilder().build(reader);// 创建能执行映射文件中sql的sqlSessionsession = sessionFactory.openSession();} catch (FileNotFoundException e) {e.printStackTrace();} catch (IOException e) {e.printStackTrace();}}
}
测试：
public class UserDao extends MyBatisBaseDao {public User findUserById(int userId) {String statement = "com.dao.IUserDao.getUserById";// 映射sql的标识字符串// 执行查询返回一个唯一user对象的sql// UserDao.init();System.out.println(session);/**使用mybatis的代理 方法一*/IUserDao DAO=session.getMapper(IUserDao.class);User user=DAO.getUserById(8);/**方法二**/
// User user = session.selectOne(statement, userId);
System.out.println(user);return user;}public static void main(String[] args) {UserDao dao = new UserDao();dao.findUserById(8);}
}
注：也可以不使用接口
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