MyBatis ---- 搭建MyBatis
1. 开发环境
IDE：idea 2022.1
构建工具：maven 3.8.1
MySql 版本：MySql 8
MyBatis 版本：MyBatis 3.5.11
2. 创建maven工程
a>打包方式：jar
<groupId>org.example</groupId>
<artifactId>MyBatis_demo1</artifactId>
<version>1.0-SNAPSHOT</version>
<packaging>jar</packaging>
b>引入依赖
<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>5.1.3</version>
</dependency>
</dependencies>
3. 创建MyBatis的核心配置文件
<?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>
<!--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.jdbc.Driver"/>
<property name="url"
value="jdbc:mysql://localhost:3306/mybatis?useUnicode=true&characterEncoding=utf8&serverTimezone=UTC&useSSL=false&rewriteBatchedStatements=true"/>
<property name="username" value="root"/>
<property name="password" value="root"/>
</dataSource>
</environment>
</environments>
<!--引入映射文件-->
<mappers>
<mapper resource="mappers/UserMapper.xml"/>
</mappers>
</configuration>
4. 创建mapper接口
- 在数据库中创建
t_user表
- 在 项目中创建对应数据库
t_user表的实体类
package com.fickler.mybatis.pojo;
/**
* @author dell
* @version 1.0
*/
public class User {
private Integer id;
private String username;
private String password;
private Integer age;
private String sex;
private String email;
public User() {
}
public User(Integer id, String username, String password, Integer age, String sex, String email) {
this.id = id;
this.username = username;
this.password = password;
this.age = age;
this.sex = sex;
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 getSex() {
return sex;
}
public void setSex(String sex) {
this.sex = sex;
}
public String getEmail() {
return email;
}
public void setEmail(String email) {
this.email = email;
}
@Override
public String toString() {
return "User{" +
"id=" + id +
", username='" + username + '\'' +
", password=（排除文章风险提示）'" + password + '\'' +
", age=" + age +
", sex='" + sex + '\'' +
", email='" + email + '\'' +
'}';
}
}
- 创建 mapper 接口
package com.fickler.mybatis.mapper;
/**
* @author dell
* @version 1.0
*/
public interface UserMapper {
/**
* MyBatis面向接口编程的两个一致：
* 1.映射文件的namespace要和mapper接口的全类名保持一致
* 2.映射文件中的SQL语句的id要和mapper接口中的方法名保持一致
* 表--实体类--mapper接口--映射文件
*/
/**
* 添加用户信息
*/
int insertUser();
}
5. 创建MyBatis的映射文件
相关概念：ORM（Object Relationship Mapping）对象关系映射。
对象：Java 的实体类对象
关系：关系型数据库
映射：二者之间的对应关系
| Java概念 | 数据库概念 |
|---|---|
| 类 | 表 |
| 属性 | 字段/列 |
| 对象 | 记录/行 |
<?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.fickler.mybatis.mapper.UserMapper">
<!--int insertUser();-->
<insert id="insertUser">
insert into t_user values(null,'张三','123',23,'女','123456@qq.com')
</insert>
</mapper>
6. 通过junit测试功能
package com.fickler.mybatis.test;
import com.fickler.mybatis.mapper.UserMapper;
import com.fickler.mybatis.pojo.User;
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 org.junit.Test;
import java.io.IOException;
import java.io.InputStream;
/**
* @author dell
* @version 1.0
*/
public class MyBatisTest {
/**
* SqlSession默认不自动提交事务，若需要自动提交事务
* 可以使用sqlSessionFactory.openSession(true);
* @throws IOException
*/
@Test
public void testMyBatis() throws IOException {
//加载核心配置文件
InputStream resourceAsStream = Resources.getResourceAsStream("mybatis-config.xml");
//获取SqlSessionFactoryBuilder
SqlSessionFactoryBuilder sqlSessionFactoryBuilder = new SqlSessionFactoryBuilder();
//获取sqlSessionFactory
SqlSessionFactory sqlSessionFactory = sqlSessionFactoryBuilder.build(resourceAsStream);
//获取SqlSession
SqlSession sqlSession = sqlSessionFactory.openSession(true); //自动提交
//获取mapper接口对象
UserMapper userMapper = sqlSession.getMapper(UserMapper.class);
//测试功能
int result = userMapper.insertUser();
//提交事务
// sqlSession.commit();
System.out.println("result: " + result);
}
}
7. 加入log4j日志功能
a>加入依赖
<!-- log4j日志 -->
<dependency>
<groupId>log4j</groupId>
<artifactId>log4j</artifactId>
<version>1.2.17</version>
</dependency>
b>加入log4j的配置文件
<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE log4j:configuration SYSTEM "log4j.dtd">
<log4j:configuration>
<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>
