提示：文章写完后，目录可以自动生成，如何生成可参考右边的帮助文档
文章目录
前言
提示：这里可以添加本文要记录的大概内容：
例如：随着人工智能的不断发展，机器学习这门技术也越来越重要，很多人都开启了学习机器学习，本文就介绍了机器学习的基础内容。
提示：以下是本篇文章正文内容，下面案例可供参考
一、Mybatis是什么
MyBatis 是一款优秀的持久层框架，它支持自定义 SQL、存储过程以及高级映射。MyBatis 免除了几乎所有的 JDBC 代码以及设置参数和获取结果集的工作。MyBatis 可以通过简单的 XML 或注解来配置和映射原始类型、接口和 Java POJO（Plain Old Java Objects，普通老式 Java 对象）为数据库中的记录
二、使用步骤
1.使用Maven导入jar包
代码如下（示例）：
</properties>-->
<dependencies>
<dependency>
<groupId>org.mybatis</groupId>
<artifactId>mybatis</artifactId>
<version>3.4.1</version>
</dependency>
<dependency>
<groupId>mysql</groupId>
<artifactId>mysql-connector-mxj</artifactId>
<version>5.0.12</version>
</dependency>
<dependency>
<groupId>junit</groupId>
<artifactId>junit</artifactId>
<version>4.12</version>
<scope>test</scope>
</dependency>
</dependencies>
<build>
<resources>
<!-- resources文件 -->
<resource>
<directory>src/main/java</directory>
<!-- 引入映射文件等 -->
<includes>
<include>**/*.xml</include>
</includes>
</resource>
</resources>
</build>
2.创建Mbatis工具类
<mapper resource="Dao/UrseMapper.xml"/>这个是自己写的接口的xml文件
代码如下（示例）：
private static SqlSessionFactory sqlSessionFactory;
static {
InputStream inputStream = null;
try {
String resource="mybatis-config.xml";
inputStream = Resources.getResourceAsStream(resource);
sqlSessionFactory = new SqlSessionFactoryBuilder().build(inputStream);
} catch (IOException e) {
e.printStackTrace();
}
}
public static SqlSession getSqlSession()
{
return sqlSessionFactory.openSession();
}
24.4.写核心配置文件
<?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>
<environments default="development">
<environment id="development">
<transactionManager type="JDBC"/>
<dataSource type="POOLED">
<property name="driver" value="com.mysql.jdbc.Driver"/>
<property name="url" value="jdbc:mysql://localhost:3306/mybatis"/>
<property name="username" value="root"/>
<property name="password" value="root"/>
</dataSource>
</environment>
</environments>
<mappers>
<mapper resource="Dao/UrseMapper.xml"/>
</mappers>
</configuration>
接口xml文件如下
<?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">
<!--namespace这个是绑定了一个接口-->
<mapper namespace="Dao.UrseMapper">
<!-- id就是对应的接口里面的方法名
resultType这个是sql语句的返回值
parameterType这个是要传入sql语句的值
-->
<select id="getList" resultType="pojo.Urse">
SELECT * FROM USER
</select>
<select id="getUserBy" resultType="pojo.Urse" parameterType="int">
select * from user where Id=#{Id}
</select>
<insert id="adduser" parameterType="pojo.Urse">
insert into user (Id,Name,Age,Sex)VALUES (#{Id},#{Name},#{Age},#{Sex})
</insert>
<update id="updateuser" parameterType="pojo.Urse">
update user set Name=#{Name},Age=#{Age},Sex=#{Sex} where Id=#{Id}
</update>
<delete id="deleteuser" parameterType="int">
delete from user where Id=#{Id}
</delete>
</mapper>
3.写实体类和接口
private int Id;
private String Name;
private int Age;
private String Sex;
public Urse() {
}
public Urse(int id, String name, int age, String sex) {
Id = id;
Name = name;
Age = age;
Sex = sex;
}
public int getId() {
return Id;
}
public void setId(int id) {
Id = id;
}
public String getName() {
return Name;
}
public void setName(String name) {
Name = name;
}
public int getAge() {
return Age;
}
public void setAge(int age) {
Age = age;
}
public String getSex() {
return Sex;
}
public void setSex(String sex) {
Sex = sex;
}
@Override
public String toString() {
return "Urse{" +
"Id=" + Id +
", Name='" + Name + '\'' +
", Age=" + Age +
", Sex='" + Sex + '\'' +
'}';
}
接口如下
public interface UrseMapper {
/*这个是查询全部用户*/
List<Urse> getList();
/*根据ID查询用户*/
Urse getUserBy(int Id);
/*添加用户*/
int adduser(Urse urse);
/*修改用户*/
int updateuser(Urse urse);
/*删除一个用户*/
int deleteuser(int Id);
}
4.创建测试类
package Dao;
import org.apache.ibatis.session.SqlSession;
import org.apache.ibatis.session.SqlSessionFactory;
import org.junit.Test;
import pojo.Urse;
import utils.MybatisUtils;
import java.util.List;
public class UrseDaoTset {
@Test
public void tset()
{
SqlSession sqlSession= MybatisUtils.getSqlSession();
UrseMapper urseMapper=sqlSession.getMapper(UrseMapper.class);
List<Urse>list=urseMapper.getList();
for (Urse urse:list
) {
System.out.println(urse);
}
sqlSession.close();
}
@Test
public void getUserBy()
{
SqlSession sqlSession=MybatisUtils.getSqlSession();
UrseMapper urseMapper=sqlSession.getMapper(UrseMapper.class);
Urse urse=urseMapper.getUserBy(3);
System.out.println(urse);
}
/*增删改需要提交事务*/
@Test
public void adduser()
{
SqlSession sqlSession=MybatisUtils.getSqlSession();
UrseMapper urseMapper=sqlSession.getMapper(UrseMapper.class);
urseMapper.adduser(new Urse(6,"龙琪",19,"女"));
sqlSession.commit();
/* sqlSession.commit();这个方法是提交事务的方法*/
sqlSession.close();
}
@Test
public void updateuser()
{
SqlSession sqlSession=MybatisUtils.getSqlSession();
UrseMapper urseMapper=sqlSession.getMapper(UrseMapper.class);
urseMapper.updateuser(new Urse(2,"黄榆坤是傻逼",999,"不男不女"));
sqlSession.commit();
sqlSession.close();
}
@Test
public void deleteuser()
{
SqlSession sqlSession=MybatisUtils.getSqlSession();
UrseMapper urseMapper=sqlSession.getMapper(UrseMapper.class);
urseMapper.deleteuser(6);
sqlSession.commit();
sqlSession.close();
}
}
需要注意的是测试类是在test包下的要和上面对src目录对应，还要注意的是增删改必须提交事务
sqlSession.commit();否则数据库不会更新。
总结
写这个的原因是作为一个笔记，作者水平有限，请各位大佬指点