1、在数据库中创建User表
2、创建Maven项目
3、导入依赖
<dependencies>
<dependency>
<groupId>org.mybatis</groupId>
<artifactId>mybatis</artifactId>
<version>3.5.7</version>
</dependency>
<dependency>
<groupId>mysql</groupId>
<artifactId>mysql-connector-java</artifactId>
<version>5.1.47</version>
</dependency>
<dependency>
<groupId>com.alibaba</groupId>
<artifactId>druid</artifactId>
<version>1.2.6</version>
</dependency>
<dependency>
<groupId>org.projectlombok</groupId>
<artifactId>lombok</artifactId>
<version>1.18.6</version>
</dependency>
</dependencies>
<build>
<resources>
<resource>
<directory>src/main/java</directory>
<includes>
<include>**/*.xml</include>
</includes>
</resource>
</resources>
</build>
4、创建user的实体类
@Data
@AllArgsConstructor
@NoArgsConstructor
public class User {
private Integer id;
private String name;
private String pwd;
}
5、创建生成sqlsession的工具类
public class MybatisUtils {
private static SqlSessionFactory sqlSessionFactory;
static {
InputStream is = null;
try {
is = Resources.getResourceAsStream("SqlMapConfig.xml");
sqlSessionFactory = new SqlSessionFactoryBuilder().build(is);
} catch (IOException e) {
e.printStackTrace();
} finally {
if (is != null) {
try {
is.close();
} catch (IOException e) {
e.printStackTrace();
}
}
}
}
/**
* 获得SqlSession
*/
public static SqlSession openSqlSession() throws IOException {
return sqlSessionFactory.openSession();
}
/**
* 提交释放资源
*/
public static void commitAndClose(SqlSession sqlSession) {
if (sqlSession != null) {
sqlSession.commit();
sqlSession.close();
}
}
/**
* 回滚释放资源
*/
public static void rollbackAndClose(SqlSession sqlSession) {
if (sqlSession != null) {
sqlSession.rollback();
sqlSession.close();
}
}
}
6、创建UserMapper接口
public interface UserMapper {
List<User> findAll();
}
7、创建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.study.dao.UserMapper">
<select id="findAll" resultType="com.study.pojo.User">
select * from user
</select>
</mapper>
8、进行测试
public static void main(String[] args) {
SqlSession session = MybatisUtils.getSession();
UserMapper mapper = session.getMapper(UserMapper.class);
List<User> all = mapper.findAll();
for (User user : all) {
System.out.println(user);
}
}
原文地址:https://blog.csdn.net/qq_41921378/article/details/122269308
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