myBati初学

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