MyBatis入门实例-包括实体类与数据库字段对应&CLOB字段处理

声明：本文大部分参考@孤傲苍狼的文章点击打开链接，在这之中加入了一些我的个人总结

1、我的开发环境是 jdk1.7+ecplise+oracle 11g

     用到的jar包：mybatis-3.1.1.jar 

ojdbc6.jar            

2、项目整体结构 

3、首先配置conf.xml文件

<?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">
<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>

4、数据库表创建

-- Create table
create table DIM_LANE_AREA
(
lane_id       NUMBER(4) not null,
lane_name     VARCHAR2(100) not null,
direction     CHAR(2) not null,
facility_list CLOB not null,
account_list  CLOB not null,
description   VARCHAR2(100)
)
tablespace USERS
pctfree 10
initrans 1
maxtrans 255
storage
(
initial 64K
next 1M
minextents 1
maxextents unlimited
);
-- Add comments to the columns
comment on column DIM_LANE_AREA.lane_id
is '单行道编号';
comment on column DIM_LANE_AREA.lane_name
is '单行道名称';
comment on column DIM_LANE_AREA.direction
is '单行道方向';
comment on column DIM_LANE_AREA.facility_list
is '设备列表';
comment on column DIM_LANE_AREA.account_list
is '账户列表';
comment on column DIM_LANE_AREA.description
is '描述';
-- Create/Recreate indexes
create unique index DIM_LANE_AREA_1 on DIM_LANE_AREA (LANE_ID)
tablespace USERS
pctfree 10
initrans 2
maxtrans 255
storage
(
initial 64K
next 8K
minextents 1
maxextents unlimited
);
create index DIM_LANE_AREA_2 on DIM_LANE_AREA (DIRECTION)
tablespace USERS
pctfree 10
initrans 2
maxtrans 255
storage
(
initial 64K
next 8K
minextents 1
maxextents unlimited
);
-- Create/Recreate primary, unique and foreign key constraints
alter table DIM_LANE_AREA
add constraint DIM_LANE_AREA primary key (LANE_ID);

5、编写实体类LaneArea.java

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 + "]";
}
}

6、配置LaneAreaMapper.xml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">
<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 -->
<!-- 根据id查询得到一个LaneArea对象 -->
<select id="getLaneAreaResultMap" parameterType="int" resultMap="LaneAreaResultMap">
select * from dim_lane_area where lane_id = #{lane_id}
</select>
<!--这里因为实体类的属性与数据库字段不对应，所以要加上resultMap-->
<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>

7、在conf.xml中注册LaneAreaMapper.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">
<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>

8、编写测试类

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);
}
}