学习Mybatis这么多天，那么我给大家分享一下我的学习成果。从最基础的开始配置。
一、创建一个web项目，看一下项目架构
二、说道项目就会想到需要什么jar
三、就是准备大配置链接Orcl数据库
<?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>
<!-- 别名的定制 -->
<typeAliases>
<!-- 按类型名定制别名 -->
<!-- <typeAlias type="cn.happy.entity.Student" alias="Student"/> -->
<!-- 拿当前指定包下的简单类名作为别名 -->
<package name="cn.happy.entity"/>
</typeAliases>
<environments default="development">
<environment id="development">
<!-- 使用jdbc的事务 -->
<transactionManager type="JDBC" />
<!-- 使用自带的连接池 -->
<dataSource type="POOLED">
<property name="driver" value="oracle.jdbc.driver.OracleDriver"/>
<property name="url" value="jdbc:oracle:thin:@localhost:1521:orcl"/>
<property name="username" value="T2" />
<property name="password" value="T2" />
</dataSource>
</environment>
</environments>
<mappers>
<mapper resource="cn/happy/dao/StudentDAO.xml" />
</mappers>
</configuration>
四、准备小配置
<?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="cn.happy.dao.IStudentDAO">//增删改 </mapper>
五、准备工具类
package cn.happy.util;
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;
/**
* 工具类
* @author Happy
*
*/
public class MybatisUtil {
private static String config="mybatis-config.xml";
static Reader reader;
static{
try {
reader= Resources.getResourceAsReader(config);
} catch (IOException e) {
e.printStackTrace();
}
}
private static SqlSessionFactory factory = new SqlSessionFactoryBuilder().build(reader);
//提供一个可以获取到session的方法
public static SqlSession getSession() throws IOException{
System.out.println("22222"+factory);
//弊病，就是工厂是
// 1.1 openSession到底做了什么
SqlSession session = factory.openSession();
System.out.println("3333");
return session;
}
}
六、准备实体类
package cn.happy.entity;
import java.util.Date;
/**
* 学生实体类
* @author Happy
*
*/
public class Student {
private Integer stuno;
private String stuname;
private Integer stuage;
private Date studate;
public String toString() {
return "Student [stuno=" + stuno + ", stuname=" + stuname + ", stuage="
+ stuage + ", studate=" + studate + "]";
}
public Integer getStuno() {
return stuno;
}
public void setStuno(Integer stuno) {
this.stuno = stuno;
}
public String getStuname() {
return stuname;
}
public void setStuname(String stuname) {
this.stuname = stuname;
}
public Integer getStuage() {
return stuage;
}
public void setStuage(Integer stuage) {
this.stuage = stuage;
}
public Date getStudate() {
return studate;
}
public void setStudate(Date studate) {
this.studate = studate;
}
}
七、下面是具体的代码增删改查前面是公用的
（一）下面实现查看所有
1在接口定义方法
//查询所有记录 public List<Student> findAll() throws IOException;
2在配置中=======>由于动态加载所以不需要实现类
<!-- 查询所有 -->
<select id="findAll" resultType="Student">
select * from student
</select>
3测试类中
IStudentDAO dao;
@Before
public void initData() throws IOException{
SqlSession session = MybatisUtil.getSession();
//动态踢出实现类
//首先要改StudentDAO.xml改成<mapper namespace="cn.happy.dao.IStudentDAO">
dao=session.getMapper(IStudentDAO.class);
}
/**
* selectALl学生
* @throws IOException
*/
@Test
public void findAll() throws IOException{
List<Student> list = dao.findAll();
for (Student student : list) {
System.out.println(student.getStuname());
}
}
（二）下面是添加
1在接口定义方法
//添加 public int addStu(Student stu) throws IOException;
2在配置中=======>由于动态加载所以不需要实现类
<insert id="insertStudent" parameterType="Student" >
insert into student(stuname,stuage,studate) values(#{stuname},#{stuage},#{studate})
<!-- sqlserver 和Mysql 只有自自增 自增时机和insert时机： 先insert返回自增值
Oracle先产生一个自增值，然后再执行insert
-->
<selectKey keyProperty="stuno" resultType="int">
<!-- Mysql的 -->
select @@identity
<!-- orcl的 -->
select sql_num.currval from dual
</selectKey>
</insert>
3测试类中
@Test
public void testAdd() throws IOException{
Student stu=new Student();
stu.setStuname("Y2161好人");
stu.setStuage(21);
stu.setStudate(new Date());
System.out.println("添加前======="+stu);
IStudentDAO dao=new StudentDAOImpl();
dao.addStu(stu);
System.out.println("添加后======="+stu);
}
（二）下面是删除
1在接口定义方法
//删除 public int delStu(int id) throws IOException;
2在配置中=======>由于动态加载所以不需要实现类
<!--删除学生 -->
<delete id="delStudent">
delete from student where stuno=#{xxx}<!-- #{xxx}随便写，起到一个占位的作用 -->
</delete>
3测试类中
/**
* 删除学生
* @throws IOException
*/
@Test
public void delStudent() throws IOException{
dao.delStu(2);
System.out.println("ok");
}
（二）下面是模糊查询
1在接口定义方法
//按照学生姓名查询学生集合（一个是实体一个是字符串其实都可以） public List<Student> findStudntByName(Student stu) throws IOException; public List<Student> findStudntByName(String stuname) throws IOException;
2在配置中=======>由于动态加载所以不需要实现类
<!--模糊查询 mysql的数据库 -->
<select id="findStudentByName" resultType="Student">
<!-- select * from student where stuname like concat(‘%‘,#{stuname},‘%‘) -->
select * from student where stuname like ‘%${value}%‘
</select>
3测试类中
/**
* 模糊查询
* @throws IOException
*/
@Test
public void findStudentByName() throws IOException{
/*Student stu=new Student();
stu.setStuname("人");*/
List<Student> list = dao.findStudntByName("人");
for (Student student : list) {
System.out.println(student.getStuname());
}
}
时间： 2024-08-07 01:40:38