1.添加依赖，在pom.xml中添加
<!--mybatis核心包-->
<dependency>
<groupId>org.mybatis</groupId>
<artifactId>mybatis</artifactId>
<version>3.3.0</version>
</dependency>
<!--MySQL的JDBC驱动包-->
<dependency>
<groupId>mysql</groupId>
<artifactId>mysql-connector-java</artifactId>
<version>5.1.29</version>
</dependency>
2. 添加Entity
public class UsersEntity {
private Integer userid;
private String username;
public Integer getUserid() {
return userid;
}
public void setUserid(Integer userid) {
this.userid = userid;
}
public String getUsername() {
return username;
}
public void setUsername(String username) {
this.username = username == null ? null : username.trim();
}
}
3. 添加dao层的interface UsersEntityMapper.java
public interface UsersEntityMapper {
UsersEntity getUsersByPhoneNo(String phoneNo);
}
4. 添加mapper的xml UsersEntityMapper.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.alphaomega.sunshine.dao.UsersEntityMapper">
<select id="getUsersByPhoneNo" parameterType="String" resultType="com.alphaomega.sunshine.entity.UsersEntity">
select * from users where phoneno = #{phoneNo}
</select>
</mapper>
5. 添加mybatis的配置文件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>
<environments default="development">
<environment id="development">
<transactionManager type="JDBC" />
<!-- 配置数据库连接信息 -->
<dataSource type="POOLED">
<!-- 1.加载数据库驱动 -->
<property name="driver" value="com.mysql.jdbc.Driver" />
<!-- 2.数据库连接地址 (&->&)-->
<property name="url" value="jdbc:mysql://127.0.0.1:3306/schema_name?useUnicode=true&characterEncoding=utf-8&useSSL=true" />
<!-- 数据库用户... -->
<property name="username" value="root" />
<!-- 数据库密码... -->
<property name="password" value="xxxxxxx" />
</dataSource>
</environment>
</environments>
<mappers>
<!-- 注册文件-->
<mapper resource="com/alphaomega/sunshine/mappers/UsersEntityMapper.xml"/>
<mapper resource="com/alphaomega/sunshine/mappers/XxxxxxEntityMapper.xml"/>
</mappers>
</configuration>
6. mybatis配置文件mybatis_config.xml和UsersEntityMapper.xml的位置
UsersEntityMapper.xml如果放在src/main/java里的话，则需要向pom添加路径，否则package时会报错：找不到xml文件，
原因是maven默认xml文件在src/main/resources里（不过后来发现，即使放在了默认里也不行）。
<build>
<resources>
<resource>
<directory>src/main/java</directory>
<includes>
<include>**/*.xml</include>
</includes>
</resource>
</resources>
</build>
向maven项目添加src/main/resources目录，并将mybatis_config.xml放在里面。（虽然可以通过另创建文件夹，然后use as source，但还是按照maven默认比较舒服）
添加的方式可以通过Project-Properties-Java Build Path-Source-Add Folder-选中文件夹后Create new folder...
同样，测试目录src/test/resources也通过这样执行。
问题来了，测试时没有任何问题，但是jar包不能，maven会把test目录的xml文件复制到target/test-class下，但是不会将main下的xml复制到target/class里,
除了那些mapper，因为已经指定了路径。因此还需要在pom的resources标签里指定，为了maven复制过去。
<build>
<resources>
<resource>
<directory>src/main/java</directory>
<includes>
<include>**/*.xml</include>
</includes>
</resource>
<resource>
<directory>src/main/resources</directory>
<includes>
<include>**/*.xml</include>
</includes>
</resource>
</resources>
</build>
7. 最后使用
String resouces = "mybatis_config.xml";
InputStream in = Resources.getResourceAsStream(resouces);
//读取配置文件的配置信息，利用SqlSessionFactoryBuilder创建sqlSessionFactory
SqlSessionFactory sqlSessionFactory = new SqlSessionFactoryBuilder().build(in);
//利用sqlSessionFactory打开与数据库的会话
SqlSession sqlSession = sqlSessionFactory.openSession();
try {
UsersEntityMapper ueMapper = sqlSession.getMapper(UsersEntityMapper.class);//通过sqlSession得到mapper
String no = "13299999999";
UsersEntity user = ueMapper.getUsersByPhoneNo(no);//调用mapper的方法
//只读操作不需要sqlSession.commit()
System.out.println("查询到用户...");
System.out.println(user.getUsername());
} finally {
sqlSession.close();
}
原文地址：https://www.cnblogs.com/anenyang/p/10455574.html