MyBatis

创建数据库（y2165）

MyBatis环境搭建

1.在pom.xml引入依赖

2.得替换build节点，为了让程序编译在main中所有子包下的配置文件

3.构建大配置，位于resources

<?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">

<!-- 通过这个配置文件,完成mybatis与数据库的连接 -->
<configuration><!--根节点-->
    <!--别名设定-->
     <typeAliases>
         <package name="cn.happy.entity"/>
     </typeAliases>


    <environments default="development">
        <environment id="development">


            <!--
           transactionManager:JDBC保证事务的
           update
           delete
           事务分类：JDBC:编程式事务
                       xxx.beginTransaction()

                       tx.commit()
                       tx.rollback()
                     配置式事务
                     JDBC|MANAGED
                     区别

           -->


            <!-- 配置事物管理采用JDBC  -->
            <transactionManager type="JDBC"/>

            <!--
               POOLED：MyBatis内置的连接池
               c3p0连接池
                       POOLED 、UNPOOLED  、JNDI
           -->


            <!-- POOLED:mybatis的数据源,JNDI:基于tomcat的数据源 -->
            <dataSource type="POOLED">
                <property name="driver" value="com.mysql.jdbc.Driver"/>
                <property name="url" value="jdbc:mysql:///y2165"/>
                <property name="username" value="cd"/>
                <property name="password" value="000"/>
            </dataSource>
        </environment>
    </environments>

    <mappers>

        <mapper resource="cn/happy/dao/IDeptDAO.xml"/>

    </mappers>
</configuration>

4.构建实体类

package cn.happy.entity;

/**
 * Created by lenovo on 2017/7/7.
 */
public class Dept {
    private Integer deptNo;
    private String deptName;

    public Integer getDeptNo() {
        return deptNo;
    }

    public void setDeptNo(Integer deptNo) {
        this.deptNo = deptNo;
    }

    public String getDeptName() {
        return deptName;
    }

    public void setDeptName(String deptName) {
        this.deptName = deptName;
    }
}

5.构建小配置 

<?xml version="1.0" encoding="UTF-8" ?>
<!--头文件-->
<!DOCTYPE mapper
        PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN"
        "http://mybatis.org/dtd/mybatis-3-mapper.dtd ">
<!--namespace：
命名空间：区分不同空间下的同名SQLID
A： findlAll
B:  findAll
-->

<mapper namespace="cn.happy.dao.IDeptDAO" >
    <!--SQL标签
     id:唯一锁定到SQL标识
     paramenterType:SQL语句的入参  可以省略
     resultType：
     增删除操作：不能 写
     查询：单个实体的类型
   -->
    <!--查询所有-->
    <select id="getAllList" resultType="Dept">
        SELECT * FROM Dept
    </select>
    <!--待条件查询-->
    <select id="getDeptById" parameterType="int" resultType="Dept">
        select * from Dept where deptNo=#{deptNo}
    </select>
</mapper>

6.在大配置中关联小配置

<mappers>

        <mapper resource="cn/happy/dao/IDeptDAO.xml"/>

    </mappers>

7.书写测试类

package cn.happy.test;

import cn.happy.dao.IDeptDAO;
import cn.happy.entity.Dept;
import org.apache.ibatis.io.Resources;
import org.apache.ibatis.jdbc.SQL;
import org.apache.ibatis.session.SqlSession;
import org.apache.ibatis.session.SqlSessionFactory;
import org.apache.ibatis.session.SqlSessionFactoryBuilder;
import org.junit.Test;

import java.io.IOException;
import java.io.InputStream;
import java.util.List;

/**
 * Created by lenovo on 2017/7/9.
 */
public class MyBatisTest01 {
    //单元测试
    @Test
    //1.查询所有使用getMapper()
    public void testall() {
        //1 获取到大配置
        String path = "mybatis-config.xml";
        try {
            InputStream is = Resources.getResourceAsStream(path);
            SqlSessionFactory factory = new SqlSessionFactoryBuilder().build(is);
            SqlSession session = factory.openSession();
            IDeptDAO de = session.getMapper(IDeptDAO.class);
            List<Dept> list = de.getAllList();
            for (Dept dept : list) {
                System.out.println(dept.getDeptName());
            }

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

    @Test
    //2.待条件查询  Mapper的使用
    public void testGetOneDept() {
        String path = "mybatis-config.xml";
        try {
            InputStream is = Resources.getResourceAsStream(path);
            SqlSessionFactory factory = new SqlSessionFactoryBuilder().build(is);
            SqlSession session = factory.openSession();
            IDeptDAO dao = session.getMapper(IDeptDAO.class);
            Dept dept = dao.getDeptById(1);
            System.out.println(dept.getDeptName());
        } catch (IOException e) {
            e.printStackTrace();
        }
    }

使用getMapper查询所有结果

使用getMapper带条件查询结果