mybatis基础(一)

一.查询

1.配置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>                 <!--根节点-->
    <!--引入外部文件-->
    <properties resource="jdbc.properties"></properties>
    <!--使用该包下的类的简单名称做别名-->
    <typeAliases>
    <package name="cn.happy.entity"></package>
    </typeAliases>
    <environments default="development"><!--环境-->
        <environment id="development">
            <transactionManager type="JDBC"/><!--一共两种jdbc和jdbc【manage】-->
            <dataSource type="POOLED"><!--unpolled     jndi-->
                <property name="driver" value="${jdbc.driver}"/>
                <property name="url" value="${jdbc.url}"/>
                <property name="username" value="${jdbc.username}"/>
                <property name="password" value="${jdbc.password}"/>
            </dataSource>
        </environment>
    </environments>
    <mappers>
       <!-- <mapper resource="cn/happy/dao/IUserInfoDao.xml"/>-->
        <package name="cn.happy.dao"></package>
    </mappers>
</configuration>

2.书写实体类

public class UserInfo implements Serializable {
    private  Integer userid;
    private  String username;
    private  String userpwd;
    private int usersex;

    public Integer getUserid() {
        return userid;
    }

    public void setUserid(Integer userid) {
        this.userid = userid;
    }

    public String getUsername() {
        return username;
    }

    public void setUsername(String username) {
        this.username = username;
    }

    public String getUserpwd() {
        return userpwd;
    }

    public void setUserpwd(String userpwd) {
        this.userpwd = userpwd;
    }

    public int getUsersex() {
        return usersex;
    }

    public void setUsersex(int usersex) {
        this.usersex = usersex;
    }
}

3.书写DAO层接口

package cn.happy.dao;

import cn.happy.entity.UserInfo;

import java.util.List;

/**
 * Created by 17921 on 2017/9/10.
 */
public interface IUserInfoDao {
    //查询所有
    public List<UserInfo> getList();
  }

4.书写小配置

<?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.happy.dao.IUserInfoDao"><!--关联的dao层文件-->

    <sql id="com">
        userid,username,userpwd,usersex
    </sql>
    <select id="getList"  resultMap="myUserMap" >
        select <include refid="com"></include> from userinfo

    </select>
</mapper>

5.书写测试类

    //查询所有的测试
    @Test
    public void aa(){
        String path="mybatis-config.xml";
        try {
            InputStream is= Resources.getResourceAsStream(path);
            SqlSessionFactory session=new SqlSessionFactoryBuilder().build(is);
            SqlSession sqlSession = session.openSession();
           // List<UserInfo> list = sqlSession.selectList("cn.happy.dao.IUserInfoDao.getList");
            IUserInfoDao infoDao = sqlSession.getMapper(IUserInfoDao.class);
            List<UserInfo> list = infoDao.getList();
            for (UserInfo item:list) {
                System.out.println(item.getUsername()+"	"+item.getUsersex()+"	"+item.getUserpwd());

            }
            sqlSession.close();
        } catch (IOException e) {
            e.printStackTrace();
        }
    }

注:修改,添加,删除类似