mybatis（一）环境的搭建

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE configuration PUBLIC "-//mybatis.org//DTD Config 3.0//EN" "http://www.mybatis.org/dtd/mybatis-3-config.dtd">
<!--    configuration根标签             -->
<configuration>
    <!--    二、（1）定义实体bean名和数据库列名相对应  type：实体的路径   alias：实体的别名         -->
    <typeAliases>
        <typeAlias type="com.ckx.entity.User" alias="User" />
    </typeAliases>
    
    <!--    一、    配置环境信息          -->
    <environments default="development">
        <environment id="development">
            <!--    指定事务管理机制          -->
            <transactionManager type="JDBC"></transactionManager>
            <!--    配置数据源   POOLED: 连接池         -->
            <dataSource type="POOLED">
                <property name="driver" value="com.mysql.jdbc.Driver" />
                <property name="url" value="jdbc:mysql://localhost:3306/ssm001?useUnicode=true&amp;characterEncoding=utf8" />
                <property name="username" value="root" />
                <property name="password" value="123456" />
            </dataSource>
        </environment> 
    </environments>
    <!--     二、 （2）引入关系映射文件!!!这里有严格顺序！不能放在数据源配置前    -->
    <mappers>
        <mapper resource="com/ckx/entityMapper/User.xml" />
    </mappers>
    

</configuration>

package com.ckx.entity;

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;
    }

}

<?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="com.ckx.entityMapper.User">
    
    <select id="selectRoolByuserId" parameterType="int" resultType="User">
        select * from ckx_user where UserId=#{UserId}
    </select>
    
    
</mapper>

package com.ckx.test;

import java.io.IOException;
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;

import com.ckx.entity.User;

public class UserlTest {
    //获取org.apache.ibatis.session.SqlSessionFactory很重要
    static SqlSessionFactory sessionFactory;
    static Reader reader;
    public User user;
    
    static{
        try {
            //获取org.apache.ibatis.io.Resources从config.xml的读入流
            reader= Resources.getResourceAsReader("config.xml");
            sessionFactory = new SqlSessionFactoryBuilder().build(reader);
        } catch (IOException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
    }

    //从数据库读取一条信息
    private void selectRoolByuserId() {
        SqlSession session = sessionFactory.openSession();
        user= session.selectOne("com.ckx.entityMapper.User.selectRoolByuserId",1 );
        System.out.println(user.getUserName());
    }
    
    
    public static void main(String[] args) {
        UserlTest ut = new UserlTest();
        ut.selectRoolByuserId();

    }

}