首先对mybatis进行一个简单的介绍，然后从最基础的准备工作开始搭建一个mybatis的开发
环境，最后通过简单的增删改查来熟悉配置文件和映射文件的编写。
目录
1.Mybaits简介
2.开发环境和准备工作
2.1开发环境
2.2pom文件
2.3数据库和表
2.4对应实体类
3.核心配置文件
3.1核心配置文件详解
3.1.1mybatis-config.xml
3.1.2environments
3.1.3environment
3.1.4properties
3.1.5typeAliases
3.1.6mappers
4.mapper接口和映射文件
4.1mapper接口
4.2映射文件
5.测试添加用户功能
6.优化功能
6.1加入log4j日志功能
6.2日志级别
7.测试删除和修改
7.1修改Mapper接口
7.2修改配置文件（UserMapper.xml）
7.3编写测试
8.测试查询功能
1.Mybaits简介
2.开发环境和准备工作
2.1开发环境
2.2pom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>org.example</groupId>
<artifactId>mybatis01</artifactId>
<version>1.0-SNAPSHOT</version>
<packaging>jar</packaging>
<dependencies>
<!-- Mybatis核心 -->
<dependency>
<groupId>org.mybatis</groupId>
<artifactId>mybatis</artifactId>
<version>3.5.7</version>
</dependency>
<!-- junit测试 -->
<dependency>
<groupId>junit</groupId>
<artifactId>junit</artifactId>
<version>4.12</version>
<scope>test</scope>
</dependency>
<!-- MySQL驱动 -->
<dependency>
<groupId>mysql</groupId>
<artifactId>mysql-connector-java</artifactId>
<version>8.0.16</version>
</dependency>
</dependencies>
</project>2.3数据库和表
2.4对应实体类
package com.ykx.mybatis.pojo;
/**
* @author: yangkx
* @Title: User
* @ProjectName: SSMStudy
* @Description:
* @date: 2023-06-07 17:07
*/
public class User {
private Integer id;
private String username;
private String password;
private Integer age;
private String gender;
private String email;
public User() {
}
public User(Integer id, String username, String password, Integer age, String gender, String email) {
this.id = id;
this.username = username;
this.password = password;
this.age = age;
this.gender = gender;
this.email = email;
}
public Integer getId() {
return id;
}
public void setId(Integer id) {
this.id = id;
}
public String getUsername() {
return username;
}
public void setUsername(String username) {
this.username = username;
}
public String getPassword() {
return password;
}
public void setPassword(String password) {
this.password = password;
}
public Integer getAge() {
return age;
}
public void setAge(Integer age) {
this.age = age;
}
public String getGender() {
return gender;
}
public void setGender(String gender) {
this.gender = gender;
}
public String getEmail() {
return email;
}
public void setEmail(String email) {
this.email = email;
}
@Override
public String toString() {
return "User{" +
"id=" + id +
", username='" + username + '\'' +
", password='" + password + '\'' +
", age=" + age +
", gender='" + gender + '\'' +
", email='" + email + '\'' +
'}';
}
}
3.核心配置文件
在src下main里的resources里新建mybatis-config.xml 文件
xml文件里输入如下配置：
<?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>
<!--设置连接数据库的环境-->
<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/ssm?serverTimezone=UTC"/>
<property name="username" value="root"/>
<property name="password" value="ykxykx"/>
</dataSource>
</environment>
</environments>
<!--引入映射文件-->
<mappers>
<mapper resource="mappers/UserMapper.xml"/>
</mappers>
</configuration>3.1核心配置文件详解
3.1.1mybatis-config.xml
3.1.2environments
3.1.3environment
3.1.4properties
3.1.5typeAliases
3.1.6mappers
4.mapper接口和映射文件
4.1mapper接口
MyBatis中的mapper接口相当于以前的dao
区别在于mapper仅仅是接口，不需要提供实现类
public interface UserMapper {
/**
* 添加用户信息
*/
int insertUser();
}4.2映射文件
Mapper.xml 文件
5.测试添加用户功能
public class MyBatisTest {
@Test
public void test() throws Exception{
//获取核心配置文件的输入流
InputStream is = Resources.getResourceAsStream("mybatis-config.xml");
//创建SqlSessionFactoryBuilder对象
SqlSessionFactoryBuilder sqlSessionFactoryBuilder = new SqlSessionFactoryBuilder();
//通过核心配置文件所对应的字节输入流创建工厂类SqlSessionFactory，生产SqlSession对象
SqlSessionFactory sqlSessionFactory = sqlSessionFactoryBuilder.build(is);
//创建SqlSession对象，此时通过SqlSession对象所操作的sql都必须手动提交或回滚事务
//SqlSession sqlSession = sqlSessionFactory.openSession();
//创建SqlSession对象，此时通过SqlSession对象所操作的sql都会自动提交
SqlSession sqlSession = sqlSessionFactory.openSession(true);
//通过代理模式创建UserMapper接口的代理实现类对象
UserMapper userMapper = sqlSession.getMapper(UserMapper.class);
//调用UserMapper接口中的方法，就可以根据UserMapper的全类名匹配元素文件，通过调用的方法名匹配映射文件中的SQL标签，并执行标签中的SQL语句
int result = userMapper.insertUser();
//sqlSession.commit();
System.out.println("结果："+result);
sqlSession.close();
}
}
6.优化功能
6.1加入log4j日志功能
<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE log4j:configuration SYSTEM "log4j.dtd">
<log4j:configuration xmlns:log4j="http://jakarta.apache.org/log4j/">
<appender name="STDOUT" class="org.apache.log4j.ConsoleAppender">
<param name="Encoding" value="UTF-8" />
<layout class="org.apache.log4j.PatternLayout">
<param name="ConversionPattern" value="%-5p %d{MM-dd HH:mm:ss,SSS}%m (%F:%L) \n" />
</layout>
</appender>
<logger name="java.sql">
<level value="debug" />
</logger>
<logger name="org.apache.ibatis">
<level value="info" />
</logger>
<root>
<level value="debug" />
<appender-ref ref="STDOUT" />
</root>
</log4j:configuration>6.2日志级别
7.测试删除和修改
提取出创造sqlsession的工具类
public class SqlSessionUtil {
public static SqlSession getSqlSession(){
SqlSession sqlSession = null;
try {
InputStream is = Resources.getResourceAsStream("mybatis-config.xml");
SqlSessionFactoryBuilder sqlSessionFactoryBuilder = new SqlSessionFactoryBuilder();
SqlSessionFactory sqlSessionFactory = sqlSessionFactoryBuilder.build(is);
sqlSession = sqlSessionFactory.openSession(true);
} catch (IOException e) {
e.printStackTrace();
}
return sqlSession;
}
}7.1修改Mapper接口
7.2修改配置文件（UserMapper.xml）
<!--int insertUser();-->
<insert id="insertUser">
insert into t_user values(null,'admin','123456',23,'男','12345@qq.com')
</insert>
<update id="updateUser">
update t_user set username='root',password='123' where id=1;
</update>
<delete id="deleteUser">
delete from t_user where id=3
</delete>7.3编写测试
@Test
public void test2(){
SqlSession sqlSession = SqlSessionUtil.getSqlSession();
UserMapper userMapper = sqlSession.getMapper(UserMapper.class);
int result = userMapper.updateUser();
System.out.println("结果：" + result);
sqlSession.close();
}@Test
public void test3(){
SqlSession sqlSession = SqlSessionUtil.getSqlSession();
UserMapper mapper = sqlSession.getMapper(UserMapper.class);
mapper.deleteUser();
sqlSession.close();
}8.测试查询功能
@Test
public void test4(){
SqlSession sqlSession = SqlSessionUtil.getSqlSession();
UserMapper mapper = sqlSession.getMapper(UserMapper.class);
User userById = mapper.getUserById();
System.out.println(userById);
sqlSession.close();
}
