MyBatis入门学习

来源：互联网发布：数据分析的好处编辑：程序博客网时间：2024/05/29 02:19

所需要jar包：mybatis-3.x.x.jar 、如果需要和spring整合，还需要加入相关的包

1：看项目目录红颜色不要关心

2：按照步骤：

1：加入jar包

2：创建数据源（configuration.xml）创建数据库（此处省略）

<?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>      <typeAliases>          <!--给实体类起一个别名 user -->          <typeAlias type="com.forum.po.User" alias="User" />      </typeAliases>      <!--数据源配置  这块用 BD2数据库 -->      <environments default="development">          <environment id="development">              <transactionManager type="jdbc" />              <dataSource type="POOLED">                  <property name="driver" value="com.ibm.db2.jcc.DB2Driver" />                  <property name="url" value="jdbc:db2://localhost:50000/forum" />                  <property name="username" value="DB2ADMIN" />                  <property name="password" value="admin" />              </dataSource>          </environment>      </environments>      <mappers>          <!--userMapper.xml装载进来  同等于把“dao”的实现装载进来 -->          <mapper resource="myBatis/userMapper.xml" />      </mappers>  </configuration>

3：创建实体类USER

package com.forum.po;    /**  * 用户类  *   * @author db2admin  *   */  public class User extends Entity {      private String name;      private Integer age;      public String getName() {          return name;      }      public void setName(String name) {          this.name = name;      }      public Integer getAge() {          return age;      }      public void setAge(Integer age) {          this.age = age;      }      public User() {      }    }

4：创建dao接口、可以说是Mapper接口：UserMapper

package com.forum.dao;    import com.forum.po.User;    public interface UserMapper {      public User findById(String Id);  }

5:创建dao的实现，不同于hibernarte的此处的实现为一个xml文件，也就是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">      <!--这块等于dao接口的实现  namespace必须和接口的类路径一样-->  <mapper namespace="com.forum.dao.UserMapper">      <!-- findById必须和接口中的方法名一样  返回一个User  就是刚才的别名  如果不弄别名要连类路径一起写 麻烦-->      <select id="findById" parameterType="HashMap" resultType="User">          select          * from butone.student where id=#{id}      </select>  </mapper>

6:测试类，MyBatisTest

package com.forum.test;    import java.io.IOException;    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 com.forum.dao.UserMapper;  import com.forum.po.User;    /**  * myBatis数据库连接测试  *   * @author db2admin  *   */  public class MyBatisTest {      /**      * 获得MyBatis SqlSessionFactory        * SqlSessionFactory负责创建SqlSession，一旦创建成功，就可以用SqlSession实例来执行映射语句，commit，rollback，close等方法。      * @return      */      private static SqlSessionFactory getSessionFactory() {          SqlSessionFactory sessionFactory = null;          String resource = "configuration.xml";          try {              sessionFactory = new SqlSessionFactoryBuilder().build(Resources                      .getResourceAsReader(resource));          } catch (IOException e) {              // TODO Auto-generated catch block              e.printStackTrace();          }          return sessionFactory;      }        public static void main(String[] args) {          SqlSession sqlSession = getSessionFactory().openSession();          UserMapper userMapper = sqlSession.getMapper(UserMapper.class);          User user = userMapper.findById("1");          System.out.println(user.getName());        }    }

0 0