【Mybatis】（一）MyBatis入门 & 第一个MyBatis实例

package cn.kgc.entity;
import java.util.Date;
public class User {
  private Integer id; //id 
  private String userCode; //用户编码
  private String userName; //用户名称
  private String userPassword; //用户密码
  private Integer gender;  //性别
  private Date birthday;  //出生日期
  private String phone;   //电话
  private String address; //地址
  private Integer userRole;    //用户角色
  private Integer createdBy;   //创建者
  private Date creationDate; //创建时间
  private Integer modifyBy;     //更新者
  private Date modifyDate;   //更新时间
  private Integer age;//年龄
  private String userRoleName;    //用户角色名称
  public String getUserRoleName() {
  return userRoleName;
  }
  public void setUserRoleName(String userRoleName) {
  this.userRoleName = userRoleName;
  }
  public Integer getAge() {
  /*long time = System.currentTimeMillis()-birthday.getTime();
  Integer age = Long.valueOf(time/365/24/60/60/1000).IntegerValue();*/
  Date date = new Date();
  Integer age = date.getYear()-birthday.getYear();
  return age;
  }
  public Integer getId() {
  return id;
  }
  public void setId(Integer id) {
  this.id = id;
  }
  public String getUserCode() {
  return userCode;
  }
  public void setUserCode(String userCode) {
  this.userCode = userCode;
  }
  public String getUserName() {
  return userName;
  }
  public void setUserName(String userName) {
  this.userName = userName;
  }
  public String getUserPassword() {
  return userPassword;
  }
  public void setUserPassword(String userPassword) {
  this.userPassword = userPassword;
  }
  public Integer getGender() {
  return gender;
  }
  public void setGender(Integer gender) {
  this.gender = gender;
  }
  public Date getBirthday() {
  return birthday;
  }
  public void setBirthday(Date birthday) {
  this.birthday = birthday;
  }
  public String getPhone() {
  return phone;
  }
  public void setPhone(String phone) {
  this.phone = phone;
  }
  public String getAddress() {
  return address;
  }
  public void setAddress(String address) {
  this.address = address;
  }
  public Integer getUserRole() {
  return userRole;
  }
  public void setUserRole(Integer userRole) {
  this.userRole = userRole;
  }
  public Integer getCreatedBy() {
  return createdBy;
  }
  public void setCreatedBy(Integer createdBy) {
  this.createdBy = createdBy;
  }
  public Date getCreationDate() {
  return creationDate;
  }
  public void setCreationDate(Date creationDate) {
  this.creationDate = creationDate;
  }
  public Integer getModifyBy() {
  return modifyBy;
  }
  public void setModifyBy(Integer modifyBy) {
  this.modifyBy = modifyBy;
  }
  public Date getModifyDate() {
  return modifyDate;
  }
  public void setModifyDate(Date modifyDate) {
  this.modifyDate = modifyDate;
  }
}

<?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>
    <properties resource="database.properties">
    </properties>
    <!--<settings>-->
    <!--<setting name="logImpl" value="LOG4J"/>-->
    <!--</settings>-->
    <environments default="development">
        <environment id="development">
            <transactionManager type="JDBC"></transactionManager>
            <!-- 数据库连接的配置信息 驱动，URL，用户名，密码-->
            <dataSource type="POOLED">
                <property name="driver" value="${driver}"/>
                <property name="url" value="${url}"/>
                <property name="username" value="${user}"/>
                <property name="password" value="${password}"/>
            </dataSource>
        </environment>
    </environments>
    <!-- 将mapper映射文件加入到系统核心配置文件中 -->
    <mappers>
        <mapper resource="cn/kgc/dao/user/UserMapper.xml"/>
    </mappers>
</configuration>

<?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="cn.kgc.dao.user.UserMapper">
    <select id="cnt" resultType="int">
        select count(1) from smbms_user
    </select>
    <select id="user" resultType="cn.kgc.entity.User">
        select * from smbms_user
    </select>
</mapper>

package cn.kgc.dao.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.*;
import java.io.IOException;
import java.io.InputStream;
public class UserMapperTest {
    @Test
    public void test(){
        //测试方法
        SqlSessionFactory factory=null;
        SqlSession session=null;
        int count=0;
    /**
     * 1、根据xml配置文件（全局配置文件）创建一个SqlSessionFactory对象 有数据源的运行环境信息
     * 2、sql映射文件；配置了每一个sql，以及sql的封装规则等。 
     * 3、将sql映射文件注册在全局配置文件中
     * 4、写代码：
     *      1）、根据全局配置文件得到SqlSessionFactory；
     *      2）、使用sqlSession工厂，获取到sqlSession对象使用他来执行增删改查
     *          一个sqlSession就是代表和数据库的一次会话，用完关闭
     *      3）、使用sql的唯一标志来告诉MyBatis执行哪个sql。sql都是保存在sql映射文件中的。
     * 
     * @throws IOException
     */
        try {
            //1.读取mybatis配置，转成io流
            InputStream is= Resources.getResourceAsStream("mybatis-config.xml");
            //2.利用io流对factory对象赋值
            factory= new SqlSessionFactoryBuilder().build(is);
            //3.由工厂创建SqlSession对象
            session=factory.openSession();
            //由session对象进行语句查询
            count=session.selectOne("cn.kgc.dao.user.UserMapper.cnt");
            System.out.println(count);
        } catch (IOException e) {
            e.printStackTrace();
        }
    }
}

读取XML文件构造方式：
String resource = "mybatis-config.xml";  　
InputStream is = Resources.getResourceAsStream(resource);  　
SqlSessionFactory sqlSessionFactory = new SqlSessionFactoryBuilder().build(is);

SqlSession session = sqlSessionFactory.openSession(boolean autoCommit);