MyBatis入门实例-包括实体类与数据库字段对应&CLOB字段处理

2022-10-26 12:11:19

1、我的开发环境是 jdk1.7+ecplise+oracle 11g

<?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="oracle.jdbc.driver.OracleDriver" />
<property name="url" value="jdbc:oracle:thin:@xxx.xxx.xxx.xxx:1521:orcl" />
<property name="username" value="xxx" />
<property name="password" value="xxx" />
</dataSource>
</environment>
</environments>
</configuration>

package me.gacl.po;
/**
* 单行道配置信息PO
* @author wqq
* @time 2016-09-21
*/
public class LaneArea
{
/**
* 单行道编号
*/
private Integer laneId;
/**
* 单行道名称
*/
private String laneName;
/**
* 单行道方向
*/
private String direction;
/**
* 设备列表<span style="font-family: Arial, Helvetica, sans-serif;">（该字段为CLOB类型，以逗号分隔）</span>
*/
private String facilityList;
/**
* 账户列表（该字段为CLOB类型，以逗号分隔）
*/
private String accountList;
/**
* 描述
*/
private String description;
public Integer getLaneId() {
return laneId;
}
public void setLaneId(Integer laneId) {
this.laneId = laneId;
}
public String getLaneName() {
return laneName;
}
public void setLaneName(String laneName) {
this.laneName = laneName;
}
public String getDirection() {
return direction;
}
public void setDirection(String direction) {
this.direction = direction;
}
public String getFacilityList() {
return facilityList;
}
public void setFacilityList(String facilityList) {
this.facilityList = facilityList;
}
public String getAccountList() {
return accountList;
}
public void setAccountList(String accountList) {
this.accountList = accountList;
}
public String getDescription() {
return description;
}
public void setDescription(String description) {
this.description = description;
}
@Override
public String toString()
{
return "LaneArea [lane_id=" + laneId + ", lane_name=" + laneName + ", facility_list=" + facilityList + "]";
}
}

注意：1、我之前没有在这个实体类里加入toString()，返回了一个对象，虽然也对，但是没有直观效果，这个toString()可以直观的看到你返回的结果。

<?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="me.gacl.mapping.laneAreaMapper">
<!-- 在select标签中编写查询的SQL语句，设置select标签的id属性为getUser，id属性值必须是唯一的，
不能够重复使用parameterType属性指明查询时使用的参数类型，resultType属性指明查询返回的结果集类型
resultType="me.gacl.po.LaneArea"就表示将查询结果封装成一个LaneArea类的对象返回 LaneArea类
就是dim_lane_area表所对应的实体类 -->
<select id="getLaneAreaResultMap" parameterType="int" resultMap="LaneAreaResultMap">
select * from dim_lane_area where lane_id = #{lane_id}
</select>
<resultMap type="me.gacl.po.LaneArea" id="LaneAreaResultMap">
<id property="laneId" column="lane_id"/>
<result property="laneName" column="lane_name"/>
<result property="facilityList" column="facility_list" javaType="String" jdbcType="VARBINARY"/>
</resultMap>
</mapper>

<?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="oracle.jdbc.driver.OracleDriver" />
<property name="url" value="jdbc:oracle:thin:@192.168.1.40:1521:ETL" />
<property name="username" value="lane" />
<property name="password" value="123" />
</dataSource>
</environment>
</environments>
<mappers>
<!-- 注册LaneAreaMapper.xml文件，
LaneAreaMapper.xml位于me.gacl.mapping这个包下，所以resource写成me/gacl/mapping/LaneAreaMapper.xml-->
<mapper resource="me/gacl/mapping/laneAreaMapper.xml"/>
</mappers>
</configuration>

package me.gacl.test;
import java.io.IOException;
import java.io.InputStream;
import me.gacl.po.LaneArea;
import org.apache.ibatis.session.SqlSession;
import org.apache.ibatis.session.SqlSessionFactory;
import org.apache.ibatis.session.SqlSessionFactoryBuilder;
public class Test1 {
public static void main(String[] args) throws IOException {
//mybatis的配置文件
String resource = "conf.xml";
//使用类加载器加载mybatis的配置文件（它也加载关联的映射文件）
InputStream is = Test1.class.getClassLoader().getResourceAsStream(resource);
//构建sqlSession的工厂
SqlSessionFactory sessionFactory = new SqlSessionFactoryBuilder().build(is);
//使用MyBatis提供的Resources类加载mybatis的配置文件（它也加载关联的映射文件）
//Reader reader = Resources.getResourceAsReader(resource);
//构建sqlSession的工厂
//SqlSessionFactory sessionFactory = new SqlSessionFactoryBuilder().build(reader);
//创建能执行映射文件中sql的sqlSession
SqlSession session = sessionFactory.openSession();
/**
* 映射sql的标识字符串，
* me.gacl.mapping.userMapper是userMapper.xml文件中mapper标签的namespace属性的值，
* getUser是select标签的id属性值，通过select标签的id属性值就可以找到要执行的SQL
*/
String statement = "me.gacl.mapping.laneAreaMapper.getLaneAreaResultMap";//映射sql的标识字符串
LaneArea laneArea = session.selectOne(statement, 8);
System.out.println(laneArea);
}
}

启动Tomact，运行Test1，返回结果如下：

至此大工告成。

9、最后推荐一个自动生成实体类，Mapper.xml，DAO的工具：Mybatis-Generator