mybatis 入门

<?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">
            <!--1.这里用来环境配置 和 数据库配置  就是配置mybatis的环境    2.配置映射文件 -->
<configuration>
            <!--default 是默认的环境 -->
    <environments default="mysql">

        <!--配置一个mysql的环境  id是数据库的唯一标识 不可重复 -->
        <environment id="mysql">

            <!--transactionmanager  type= "jdbc"   表示可以使用jdbc的事物 ，提交回滚等操作-->
            <transactionManager type="JDBC"></transactionManager>

            <!--dataSource type="POOLED" 就是基于数据库连接池技术进行管理 -->
            <dataSource type="POOLED">
                 <!--property  用来配置数据库的基本连接信息-->
                <property name="driver" value="com.mysql.jdbc.Driver"/>
                <property name="url" value="jdbc:mysql://localhost:3306/qy100?CharacterEncoding=utf-8"/>
                <property name="username" value="root"/>
                <property name="password" value="root"/>
            </dataSource>
        </environment>
    </environments>

        <!--mapper 用来配置映射文件    就是我dao包中创建的mapper文件名 -->
    <mappers>
        <mapper resource="com/aaa/dao/DeptMapper.xml" />
    </mappers>

</configuration>

package com.aaa.dao;

import com.aaa.entity.Dept;

import java.util.List;

/*
*
*使用Dao接口进行操作
* 1.定义增删改
* 2.修改 映射文件
*
* */
public interface DeptDAO {
    List<Dept> queryAll();

    int insert(Dept dept);

    int update(Dept dept);

    int delete(int id);
}

package com.aaa.entity;

public class Dept {
    private int id;
    private String ename;
    private String job;
    private double sal;

    public Dept() {
    }


    public Dept(int id, String ename, String job, double sal) {
        this.id = id;
        this.ename = ename;
        this.job = job;
        this.sal = sal;
    }

    public Dept(int id, String ename) {
        this.id = id;
        this.ename = ename;
    }

    public int getId() {
        return id;
    }

    public void setId(int id) {
        this.id = id;
    }

    public String getEname() {
        return ename;
    }

    public void setEname(String ename) {
        this.ename = ename;
    }

    public String getJob() {
        return job;
    }

    public void setJob(String job) {
        this.job = job;
    }

    public double getSal() {
        return sal;
    }

    public void setSal(double sal) {
        this.sal = sal;
    }

    @Override
    public String toString() {
        return "Dept{" +
                "id=" + id +
                ", ename=‘" + ename + ‘\‘‘ +
                ", job=‘" + job + ‘\‘‘ +
                ", sal=" + sal +
                ‘}‘;
    }
}

<?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">
    <!--确保唯一的标识 通常指向dao接口的完全限定名-->
<mapper namespace="com.aaa.dao.DeptDAO">

    <!--查询命令 id="selectDept":唯一标识 resultType：返回的结果的类型 -->


    <!--通过dao接口中定义功能 进行操作SQL命令 需要修改映射文件-->

    <select id="queryAll" resultType="com.aaa.entity.Dept">
        select * from dept;
    </select>

    <insert id="insert"  parameterType="com.aaa.entity.Dept">
        insert into dept(ename,job,sal)values(#{ename},#{job},#{sal});
    </insert>

    <update id="update" parameterType="com.aaa.entity.Dept">
        update dept set ename=#{ename} where id=#{id};
    </update>
        <!--接口中定义的是int类型  这里 parametertype  返回值就是 Integer 类型-->
    <delete id="delete" parameterType="Integer">
        delete from dept where id=#{id}
    </delete>

</mapper>

package com.aaa.util;

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;
import java.io.InputStream;

public class Factory {
    private static SqlSessionFactory ssf=null;

    static{
        String resource="mybatis-config.xml";
        InputStream is=null;

        try {
            is = Resources.getResourceAsStream(resource);
            ssf = new SqlSessionFactoryBuilder().build(is);

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

    }

    public Factory() {
    }

    public static SqlSessionFactory getSsf(){
        return ssf;
    }

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

package com.aaa.test;

import com.aaa.dao.DeptDAO;
import com.aaa.entity.Dept;
import com.aaa.util.Factory;
import org.apache.ibatis.session.SqlSession;

import java.util.List;

/*
*  测试 使用接口的方式来 进行SQL命令的操作。
* */
public class TestDAO {
    public static void main(String[] args) {
        SqlSession sqlSession = Factory.getSqlSession();
        DeptDAO deptDAO = sqlSession.getMapper(DeptDAO.class);

        //1.增删改 需要事务支持  2.insert添加数据
//        deptDAO.insert(new Dept(0,"李四", "老师",0));
//        sqlSession.commit();

        //修改数据  根据id 修改名字  需要在实体类中创建对应的构造方法。
//        deptDAO.update(new Dept(1, "哈哈"));
//        sqlSession.commit();

        //删除数据
//        deptDAO.delete(4);
//        sqlSession.commit();

        //查询数据
        List<Dept> deptList = deptDAO.queryAll();

        for (Dept dept:deptList
             ) {
            System.out.println("部门信息"+dept);
        }


        sqlSession.close();
    }
}