mybatis入门基础操作数据库

//封装一个获取Session的类方法

package cn.bdqn.utils;

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 SessionUtils {
private static SqlSessionFactory factory;
static {
InputStream is;
try {
is = Resources.getResourceAsStream("mybatis-config.xml");
factory = new SqlSessionFactoryBuilder().build(is);

} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}

}

public static SqlSession getSession(){
return factory.openSession(false);

}
public static void close(SqlSession session){
if (session!=null) {
session.close();
}

}

}

//配置dao层的xml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">

<mapper namespace="cn.bdqn.dao.UserDao">
<select id="count" resultType="int">
select count(1) from student
</select>
<select id="selectAll" resultType="cn.bdqn.entity.Student">
select * from student
</select>
<delete id="deleteById" parameterType="int">

delete from student where
uid=#{uid}
</delete>
<update id="updateById" parameterType="cn.bdqn.entity.Student">
update student set uname=#{uname},upwd=#{upwd} where uid=#{uid}
</update>
<select id="selectByName" parameterType="String" resultType="cn.bdqn.entity.Student">
select *from student where uname like concat ('%',#{name},'%')
</select>
<insert id="addStu" parameterType="cn.bdqn.entity.Student" >

insert into student values(#{uid},#{uname},#{upwd})
</insert>

</mapper>

//创建一个dao层

package cn.bdqn.dao;

import java.util.List;

import cn.bdqn.entity.Student;

/**

 * @author Administrator

 *

 */

/**

 * @author Administrator

 *${date}

 *

 * @date:2018-1-11 下午4:20:57

 *

 *UserDao.javacn.bdqn.dao下午4:20:57UserDaoAdministrator

 */

/**

 * @author Administrator

 *${date}

 *

 * @date:2018-1-11 下午4:21:25

 *

 *UserDao.javacn.bdqn.dao下午4:21:25UserDaoAdministrator

 */

public interface UserDao {
/**
* @return 
*/
List<Student> selectAll();
/**
* @param name
* @return
*/
List<Student> selectByName(String name);
int deleteById(int uid);
int updateById(Student student);
int addStu(Student student);

}

package cn.bdqn.test;

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 cn.bdqn.dao.UserDao;

import cn.bdqn.entity.Student;

import cn.bdqn.utils.SessionUtils;

/**

 * @author Administrator ${date}

 * 

 * @date:2018-1-11 下午4:19:41

 * 

 *                 Test.javacn.bdqn.test下午4:19:41TestAdministrator

 */

public class Test {

public static void main(String[] args) {
/*
* InputStream is =null; try {
* is=Resources.getResourceAsStream("mybatis-config.xml");
* SqlSessionFactory factory = new SqlSessionFactoryBuilder().build(is);
* SqlSession session =factory.openSession(); int count =
* session.selectOne("cn.bdqn.dao.UserMapper.count");
* System.out.println(count); } catch (IOException e) { // TODO
* Auto-generated catch block e.printStackTrace(); } finally{ try {
* is.close(); } catch (IOException e) { // TODO Auto-generated catch
* block e.printStackTrace(); }
* 
* }
*/
/*
* SqlSession session = null; try { session = SessionUtils.getSession();
* int count =session.getMapper(UserDao.class).deleteById(1);
* session.commit(); if (count>0) { System.out.println("删除成功"); }else {
* System.out.println("失败"); } } catch (Exception e) { // TODO
* Auto-generated catch block e.printStackTrace(); session.rollback(); }
*/
/* List<Student> students=session.getMapper(UserDao.class).selectAll(); */
/*
* for (Student student : students) {
* System.out.println(student.toString()); }
*/
/* System.out.println(count); */

/*
* SqlSession session = null; try { Student student= new Student();
* student.setUid(2); student.setUname("qqqqq");
* student.setUpwd("ccccc");
* 
* session = SessionUtils.getSession(); int count
* =session.getMapper(UserDao.class).updateById(student);
* session.commit(); if (count>0) { System.out.println("删除成功"); }else {
* System.out.println("失败"); } } catch (Exception e) { // TODO
* Auto-generated catch block e.printStackTrace(); session.rollback(); }
* SessionUtils.close(session);
*/
/*
* SqlSession session = null; try {
* 
* 
* session = SessionUtils.getSession(); List<Student>
* students=session.getMapper(UserDao.class).selectByName("q"); for
* (Student student : students) {
* System.out.println(student.toString()); }
* 
* } catch (Exception e) { // TODO Auto-generated catch block
* e.printStackTrace(); session.rollback(); }
* SessionUtils.close(session);
*/
SqlSession session = null;
try {

Student student = new Student();
student.setUid(4);
student.setUname("gh676h6");
student.setUpwd("ccch46h4cc");
session = SessionUtils.getSession();
int count = session.getMapper(UserDao.class).addStu(student);
System.out.println(count);

} catch (Exception e) {
// TODO Auto-generated catch block
e.printStackTrace();
session.rollback();
}
SessionUtils.close(session);

}

}