入门程序

依赖

<dependency>
    <groupId>mysql</groupId>
    <artifactId>mysql-connector-java</artifactId>
    <version>5.1.48</version>
</dependency>

<dependency>
    <groupId>org.mybatis</groupId>
    <artifactId>mybatis</artifactId>
    <version>3.4.3</version>
</dependency>

示例项目

主配置文件

mybatis.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"/>
      <dataSource type="POOLED">
        <property name="driver" value="com.mysql.jdbc.Driver"/>
        <property name="url" value="jdbc:mysql://192.168.2.130:3306/mytest"/>
        <property name="username" value="root"/>
        <property name="password" value="password"/>
      </dataSource>
    </environment>
  </environments>
  <mappers>
    <mapper resource="mapper/usersMapper.xml"/>
  </mappers>
</configuration>

映射配置文件

<?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">
<!--namespace 命名空间
    通常情况，命名空间的值，就是当前操作实体类的全名称
 -->
<mapper namespace="com.damu.eneity.Users">
  <select id="usersList" resultType="com.damu.entity.Users">
    select * from users
  </select>
</mapper>

定义实体类

package com.damu.entity;

public class Users {
  private Integer id;
  private String username;
  private String userpass;
  private String nickname;

  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 getUserpass() {
    return userpass;
  }

  public void setUserpass(String userpass) {
    this.userpass = userpass;
  }

  public String getNickname() {
    return nickname;
  }

  public void setNickname(String nickname) {
    this.nickname = nickname;
  }
}

查询操作

public class TestDemo {
  @Test
  public void testDemo1() throws IOException {
    String resource = "mybatis.xml";
    InputStream is = Resources.getResourceAsStream(resource);
    SqlSessionFactory factory = new SqlSessionFactoryBuilder().build(is);
    SqlSession session = factory.openSession();
    List<Users> ulist = session.selectList("usersList");
    for (Users user: ulist) {
      System.out.println(user);
    }
    session.close();
  }
}