mybatis框架搭建
hello,大家好，今天教大家搭建一个基本的mybatis框架，并实现对数据库的增删改查。
1.在配置好maven的前提下，在项目的pom.xml中导入依赖：
<?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>LiuChenChuan.com</groupId>
<artifactId>mybatisRepeat</artifactId>
<version>1.0-SNAPSHOT</version>
<!--导入依赖-->
<dependencies>
<dependency>
<groupId>mysql</groupId>
<artifactId>mysql-connector-java</artifactId>
<version>5.1.26</version>
</dependency>
<!--mybatis依赖-->
<dependency>
<groupId>org.mybatis</groupId>
<artifactId>mybatis</artifactId>
<version>3.5.2</version>
</dependency>
<!--junit测试依赖-->
<dependency>
<groupId>junit</groupId>
<artifactId>junit</artifactId>
<version>4.12</version>
<scope>test</scope>
</dependency>
</dependencies>
<!--声明在资源包下建立两个配置文件-->
<build>
<resources>
<resource>
<directory>src/main/resources</directory>
<includes>
<include>**/*.properties</include>
<include>**/*.xml</include>
</includes>
<filtering>false</filtering>
</resource>
<resource>
<directory>src/main/java</directory>
<includes>
<include>**/*.properties</include>
<include>**/*.xml</include>
</includes>
<filtering>false</filtering>
</resource>
</resources>
</build>
</project>
2.接下来在创建好相应的文件夹;
这是我的项目架构;
大家建好相应的文件目录
3.在resources下建立db.properites文件（用于配置连接数据库的信息）
#编写驱动
driver=com.mysql.jdbc.Driver
#编写url
url=jdbc:mysql://localhost:3306/mybatis?useSSL=false&useUnicode=true&characterEncoding=UTF-8
#连接的数据名
username=root
#数据库的密码
pwd=000000
4.接下来是mybatis核心配置文件mybatis-config.xml
<?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>
<!--导入外部配置文件-->
<properties resource="db.properties"/>
<!--设置别名-->
<typeAliases>
<package name="com.xmcu.pojo"/>
</typeAliases>
<!--默认一套环境-->
<environments default="development">
<environment id="development">
<transactionManager type="JDBC"/>
<dataSource type="POOLED">
<property name="driver" value="${driver}"/>
<property name="url" value="${url}"/>
<property name="username" value="${username}"/>
<property name="password" value="${pwd}"/>
</dataSource>
</environment>
</environments>
<mappers>
<!--在这里记住，每建立一个mapper.xml都要这里建立一个mapper-->
<mapper resource="com/xmcu/dao/UserMapper.xml"/>
</mappers>
</configuration>
5.然后在utils文件夹下建立一个工具类 MybatisUtils
package com.xmcu.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;
//利用工具类将那些资源加载进来
public class MybatisUtils {
private static SqlSessionFactory sqlSessionFactory;
static{
try {
//使用mybatis第一步：获取sqlsessionFactory对象
String resource ="mybatis-config.xml";
InputStream inputStream = Resources.getResourceAsStream(resource);
sqlSessionFactory = new SqlSessionFactoryBuilder().build(inputStream);
} catch (IOException e) {
e.printStackTrace();
}
}
//既然有了SqlSessionFactory，顾名思义我们就可以从中获得SqlSession的实例了
//SqlSession完全包含了面向数据库执行SQL命令所需的所有方法
public static SqlSession getSqlSession(){
return sqlSessionFactory.openSession();
}
}
6.然后是在pojo层创建一个实体类（对应数据库里面的数据表而建）
package com.xmcu.pojo;
public class User {
//实体类
private int uid;
private String uname;
private int uage;
public User() {
}
public User(int uid, String uname, int uage) {
this.uid = uid;
this.uname = uname;
this.uage = uage;
}
public int getUid() {
return uid;
}
public void setUid(int uid) {
this.uid = uid;
}
public String getUname() {
return uname;
}
public void setUname(String uname) {
this.uname = uname;
}
public int getUage() {
return uage;
}
public void setUage(int uage) {
this.uage = uage;
}
@Override
public String toString() {
return "User{" +
"uid=" + uid +
", uname='" + uname + '\'' +
", uage=" + uage +
'}';
}
}
7.在dao下面编写UserMapper的该接口的实现类UserMapper.xml
package com.xmcu.dao;
import com.xmcu.pojo.User;
import java.util.List;
public interface UserMapper {
//查询所有用户
List<User> getUserList();
//根据id查询一个用户
User getUserById(int id);
//insert 一个用户
int addUser(User user);
//修改一个用户
int updateUser(User user);
//删除一个用户
int deleteUser(int id);
}
UserMapper.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.xmcu.dao.UserMapper">
<!--查询所有用户-->
<select id="getUserList" resultType="com.xmcu.pojo.User">
select * from mybatis.users
</select>
<!--根据id查询用户-->
<select id="getUserById" parameterType="int" resultType="com.xmcu.pojo.User">
select * from mybatis.users where uid =#{uid}
</select>
<!--添加一个用户-->
<insert id="addUser" parameterType="com.xmcu.pojo.User">
insert into mybatis.users(uid,uname,uage)values (#{uid},#{uname},#{uage});
</insert>
<!--更新用户信息-->
<update id="updateUser" parameterType="com.xmcu.pojo.User">
update mybatis.users set uid =#{uid},uname=#{uname},uage=#{uage} where uid =#{uid};
</update>
<!--删除一个用户信息-->
<delete id="deleteUser" parameterType="int">
delete from mybatis.users where uid=#{uid};
</delete>
</mapper>
最后在Test目录下编写一个测试类：
package com.xmcu.dao;
import com.xmcu.pojo.User;
import com.xmcu.utils.MybatisUtils;
import org.apache.ibatis.session.SqlSession;
import org.junit.Test;
import java.util.List;
public class UserDaoTest {
//查询全部用户
@Test
public void getUser(){
SqlSession sqlSession = MybatisUtils.getSqlSession();
try {
UserMapper userMapper =sqlSession.getMapper(UserMapper.class);
List<User> userList = userMapper.getUserList();
for(User user : userList){
System.out.println(user);
}
} catch (Exception e) {
e.printStackTrace();
} finally {
//关闭sqlsession
sqlSession.close();
}
}
//通过id查询用户
@Test
public void getUserById(){
SqlSession sqlSession = MybatisUtils.getSqlSession();
UserMapper mapper= sqlSession.getMapper(UserMapper.class);
User user=mapper.getUserById(1);
System.out.println(user);
sqlSession.close();
}
//插入一个用户
@Test
public void insertUser(){
SqlSession sqlSession =MybatisUtils.getSqlSession();
UserMapper userMapper =sqlSession.getMapper(UserMapper.class);
int res = userMapper.addUser(new User(4,"张飞",36));
if(res>0){
System.out.println("插入成功！");
}
//提交事务
sqlSession.commit();
sqlSession.close();
}
//更新表单
@Test
public void updateUser(){
SqlSession sqlSession = MybatisUtils.getSqlSession();
UserMapper userMapper =sqlSession.getMapper(UserMapper.class);
userMapper.updateUser(new User(9,"jamess",33));
sqlSession.commit();
sqlSession.close();
}
//插入一个用户
@Test
public void deleteUser(){
SqlSession sqlSession =MybatisUtils.getSqlSession();
UserMapper userMapper = sqlSession.getMapper(UserMapper.class);
userMapper.deleteUser(9);
sqlSession.commit();
sqlSession.close();
}
}
这样就大功告成了！
部分运行结果：
通过id查询用户：
[外链图片转存失败,源站可能有防盗链机制,建议将图片保存下来直接上传(img-RVzaD1zC-1652540857697)(C:\Users\CHUAN GE PALY\Desktop\Mybatis\pictures\idSelect.jpg)]
}
//插入一个用户
@Test
public void deleteUser(){
SqlSession sqlSession =MybatisUtils.getSqlSession();
UserMapper userMapper = sqlSession.getMapper(UserMapper.class);
userMapper.deleteUser(9);
sqlSession.commit();
sqlSession.close();
}
}
这样就大功告成了！
部分运行结果：
通过id查询用户：
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