当前位置 博文首页 > 缘分锝天空的博客：第二弹：Mybatis实现CRUD的操作（Demo练习）
今天通过练习，学会了结合Mybatis框架对数据库进行简单CEUD的操作，在此记录一下。
什么是CRUD？?
?CRUD是指在做计算处理时的增加(Create)、读取查询(Retrieve)、更新(Update)和删除(Delete)几个单词的首字母简写。主要被用在描述软件系统中DataBase或者持久层的基本操作功能。
练习操作的表：stu
?
创建maven项目后，如下（用到的文件已经红色方框画出）
?重要文件的内容如下：
pom.xml文件
<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
<modelVersion>4.0.0</modelVersion>
<groupId>com.lys</groupId>
<artifactId>mybatis-demo1</artifactId>
<version>1.0-SNAPSHOT</version>
<name>demo</name>
<!-- FIXME change it to the project's website -->
<url>http://www.example.com</url>
<properties>
<project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
<maven.compiler.source>1.8</maven.compiler.source>
<maven.compiler.target>1.8</maven.compiler.target>
</properties>
<dependencies>
<dependency>
<groupId>junit</groupId>
<artifactId>junit</artifactId>
<version>4.11</version>
<scope>test</scope>
</dependency>
<dependency>
<groupId>org.mybatis</groupId>
<artifactId>mybatis</artifactId>
<version>3.5.6</version>
</dependency>
<dependency>
<groupId>mysql</groupId>
<artifactId>mysql-connector-java</artifactId>
<!--这个MySQL版本要跟自己家电脑装的mysql版本一致，否则后面报错-->
<version>8.0.17</version>
</dependency>
</dependencies>
<build>
<resources>
<resource>
<directory>src/main/java</directory>
<includes>
<include>**/*.properties </include>
<include>**/*.xml</include>
</includes>
<filtering>false</filtering>
</resource>
</resources>
</build>
</project>src\main\resources下的mybatis.xml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>
<!--数据库连接信息-->
<environments default="development">
<environment id="development">
<transactionManager type="JDBC"/>
<dataSource type="POOLED">
<property name="driver" value="com.mysql.cj.jdbc.Driver"/>
<property name="url" value="jdbc:mysql://localhost:3306/ems?useSSL=FALSE&serverTimezone=Asia/Shanghai"/>
<property name="username" value="root"/>
<property name="password" value="root"/>
</dataSource>
</environment>
</environments>
<!--sql映射文件的位置位置信息-->
<mappers>
<!--有多个继续往下写-->
<mapper resource="com/pojo/Dao/stuDao.xml"/>
</mappers>
</configuration>src\main\java\com\utils\mybatisUtils.java
package com.utils;
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 mybatisUtils {
private static SqlSessionFactory factory;
static {
// 定义主配置文件的名称，从类路径的跟开始(target/classes)
String config = "mybatis.xml";
// 读取文件
InputStream in = null;
try {
in = Resources.getResourceAsStream(config);
} catch (IOException e) {
e.printStackTrace();
}
// 创建SqlSessionFactoryBuilder对象
SqlSessionFactoryBuilder builder = new SqlSessionFactoryBuilder();
// 创建SqlSessionFactory对象
factory = builder.build(in);
}
public static SqlSession getSqlSession(){
return factory.openSession();
}
}
src\main\java\com\pojo\Dao\stuDao.java
package com.pojo.Dao;
import com.pojo.pp1.stu;
import java.util.List;
public interface stuDao {
// 查询全部学生
public List<stu> selectstu();
// 用ID查询学生
public stu findstuByID(int id);
// 添加学生
public int addstu(stu stu);
// 删除学生信息
public int deletestuById(int id);
// 修改学生信息
public int updatestu(stu stu);
}
src\main\java\com\pojo\Dao\stuDao.xml
<?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="com.pojo.Dao.stuDao">
<select id="selectstu" resultType="com.pojo.pp1.stu">
select ID,name from stu
</select>
<!--通过ID查询学生信息-->
<select id="findstuByID" parameterType="int" resultType="com.pojo.pp1.stu">
select ID,name from stu where id=#{id}
</select>
<!--添加学生-->
<insert id="addstu" parameterType="com.pojo.pp1.stu">
insert into stu(ID,name) values (#{ID},#{name})
</insert>
<!--删除学生信息-->
<delete id="deletestuById" parameterType="int" >
delete from stu where ID=#{id};
</delete>
<!--修改学生信息-->
<update id="updatestu" parameterType="com.pojo.pp1.stu">
update stu set name=#{name} where ID=#{ID}
</update>
</mapper>src\test\java\com\pojo\Dao\stuDaoTest.java（测试文件）
package com.pojo.Dao;
import com.pojo.pp1.stu;
import com.utils.mybatisUtils;
import org.apache.ibatis.jdbc.SQL;
import org.apache.ibatis.session.SqlSession;
import org.junit.Test;
import java.util.List;
public class stuDaoTest {
@Test
// 查找全部写学生的信息
public void selectstu() {
SqlSession sqlSession = mybatisUtils.getSqlSession();
stuDao stuDao = sqlSession.getMapper(com.pojo.Dao.stuDao.class);
List<stu> stuList = stuDao.selectstu();
for (stu stu : stuList) {
System.out.println(stu);
}
sqlSession.close();
}
@Test
// 通过ID查找学生
public void findstuByID(){
SqlSession sqlSession = mybatisUtils.getSqlSession();
stuDao stuDao = sqlSession.getMapper(com.pojo.Dao.stuDao.class);
stu s = stuDao.findstuByID(2);
System.out.println(s);
}
// 插入学生信息
@Test
public void addstu() {
SqlSession sqlSession = mybatisUtils.getSqlSession();
stuDao stuDao = sqlSession.getMapper(com.pojo.Dao.stuDao.class);
int a = stuDao.addstu(new stu(7, "李白"));
if (a > 0) {
System.out.println("添加学生成功！");
}
sqlSession.commit();
sqlSession.close();
}
// 删除学生信息
@Test
public void deletestuById() {
SqlSession sqlSession = mybatisUtils.getSqlSession();
stuDao stuDao = sqlSession.getMapper(com.pojo.Dao.stuDao.class);
int a = stuDao.deletestuById(2);
if (a > 0) {
System.out.println("删除学生信息成功！");
}
sqlSession.commit();
sqlSession.close();
}
@Test
public void updatestu() {
SqlSession sqlSession = mybatisUtils.getSqlSession();
stuDao stuDao = sqlSession.getMapper(com.pojo.Dao.stuDao.class);
int a = stuDao.updatestu(new stu(1, "李新"));
if (a > 0) {
System.out.println("信息修改成功!");
}
sqlSession.commit();
sqlSession.close();
}
}
努力，加油干！！！！
