mybaits2-Dao开发

项目结构：

1、创建project，导入相关依赖（前提）。配置db.properties与mybaits-config

#mysql驱动
db.driver=com.mysql.jdbc.Driver

#mysql数据库连接信息
#端口号后信息：数据库名字，是否设置数据库编码，字符编码，是否使用SSl
#SSL协议提供的服务主要有：
#1）认证用户和服务器，确保数据发送到正确的客户机和服务器；
#2）加密数据以防止数据中途被窃取；
#3）维护数据的完整性，确保数据在传输过程中不被改变。
db.url=jdbc:mysql://localhost:3306/mybatis_wjw?useUnicode=true&characterEncoding=UTF-8&useSSL=false

#数据库用户
db.username=root

#数据库密码
db.password=xxxx

　　

<?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>
    <!--加载db.properties  -->
    <properties resource="db.properties"></properties>

    <!--设置别名  -->
    <typeAliases>
        <!--单个别名设置  -->
        <!-- <typeAlias type="schema.User" alias="user"/> -->
        <package name="Dao"/>
    </typeAliases>
    <!-- mybatis环境变量配置信息 -->
    <environments default="development">
        <environment id="development">
            <!-- jdbc事务控制管理，这里由mybatis管理 -->
            <transactionManager type="JDBC"/>
            <!-- 数据源配置 -->
            <dataSource type="POOLED">
                <property name="driver" value="${db.driver}"/>
                <property name="url" value="${db.url}"/>
                <property name="username" value="${db.username}"/>
                <property name="password" value="${db.password}"/>
            </dataSource>
        </environment>
    </environments>
    <!--映射文件管理  -->
    <mappers>
        <!--通过mapper.xml文件配置  -->
        <mapper resource="dao/User.xml"/>
        <!--通过类名 必需是mapper代理开发  -->
        <!--<mapper class="dao.User"/> -->
        <!--批量配置，推荐使用  -->
        <!--<package name="dao"/>-->
    </mappers>
</configuration>

　　

2、创建单例模式SQLSessionFctory  和  SqlSession

package pubfun;

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 java.io.IOException;

public class GetSqlSession {

    public static SqlSession getSqlSession(){
        return InitSqlSessionFactory.ssf.openSession();
    }

    private static class InitSqlSessionFactory{

        private  volatile static SqlSessionFactory ssf = getSqlSessionFaactory();

        private static SqlSessionFactory getSqlSessionFaactory(){
            try {
                if(ssf==null){
                    ssf = new SqlSessionFactoryBuilder().build(Resources.getResourceAsStream("SqlMapConfig.xml") );
                }
            } catch (IOException e) {
                e.printStackTrace();
            }
            return ssf;
        }

    }

    public static void main(String args[]){
        for (int i = 0; i < 5; i++) {
            new Thread(()->{
                SqlSession ss = getSqlSession();
                System.out.println("ss:"+ss);
            }).start();
        }

    }

}

　　

3、实现Dao层

<?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="user">

    <select id="getByIdSchema" parameterType="int" resultType="schema.User">
        select * from t_user where tid = #{value}
    </select>

    <parameterMap id="UserParameter" type="java.util.Map">
        <parameter property="tid"  javaType="java.lang.Integer"></parameter>
        <parameter property="uname" javaType="java.lang.String" ></parameter>
        <parameter property="birthday" javaType="java.util.Date"></parameter>
        <parameter property="sex" javaType="java.lang.Character"></parameter>
        <parameter property="address" javaType="java.lang.String" ></parameter>
    </parameterMap>

    <resultMap id="UserResult" type="schema.User">
    <id column="id" property="tid"></id>
    <result column="name" property="uname"></result>
    <result column="birthday" property="birthday"></result>
    <result column="sex" property="sex"></result>
    <result column="address" property="address"></result>
</resultMap>

    <select id="getByConditionListSchema" parameterMap="UserParameter" resultType="schema.User">
        select * from t_user where 1=1 and  uname like concat('%',#{uname},'%') and address = #{address}
    </select>

    <!--<insert id="insertUser" parameterMap="schema.User" >-->
        <!--insert into t_user values(#{id},#{name},#{birthday},#{sex},#{address})-->
    <!--</insert>-->

    <!--<delete id="deleteUser" parameterMap="schema.User" >-->
        <!--delete  from t_user where id = #{id}-->
    <!--</delete>-->

    <!--<update id="updateUser" parameterMap="schema.User">-->
        <!--update from t_user where id = #{id}-->
    <!--</update>-->

</mapper>

　　

package dao;

import org.apache.ibatis.session.SqlSessionFactory;
import schema.User;

import java.util.List;
import java.util.Map;

public interface Dao{
    public SqlSessionFactory ssf = null;

    //使用主键查询
    public Object getByIdSchema(int i);

    //使用非主键查询返回list
    public List getByConditionListSchema(Map map);

}

　　

package dao;

import org.apache.ibatis.session.SqlSession;
import pubfun.GetSqlSession;
import schema.User;

import java.util.List;
import java.util.Map;

public class UserDao implements Dao {

    @Override
    public Object getByIdSchema(int i) {
        SqlSession ss = GetSqlSession.getSqlSession();
        User user = ss.selectOne("user.getByIdSchema",i);
        ss.close();
        return user;
    }

    @Override
    public List getByConditionListSchema(Map map) {
        SqlSession ss = GetSqlSession.getSqlSession();
        List<User> list= ss.selectList("user.getByConditionListSchema",map);
        ss.close();
        return list;
    }

}

　　

4、测试

import dao.Dao;
import dao.UserDao;
import schema.User;

import java.util.HashMap;
import java.util.List;
import java.util.Map;

public class Main {

    public static void main(String[] args) {
        Dao ud = new UserDao();
        System.out.println(ud.getByIdSchema(3));

        Map user = new HashMap();
        user.put("uname","二");
        user.put("address","湖南长沙");
        List list = ud.getByConditionListSchema(user);
        System.out.println(list);
    }
}

　　

数据库：