MyBatis入門學習-鏈接oracle實現CURD基本操做

前言

本篇記錄使用mybatis鏈接oracle數據庫實現基本的CURD操做。java

導入oracle庫

因爲oracle收費, 所以maven沒有oracle庫包,須要咱們本身導入,能夠手工導入外部包,也能夠將oracle的jar導入到maven庫種。具體導入步驟能夠查看Maven添加Oracle的依賴及驅動sql

導入mybatis庫包,我本地使用的是3.5.5版本。最後的配置以下所示數據庫

<dependency>
  <groupId>org.mybatis</groupId>
  <artifactId>mybatis</artifactId>
  <version>3.5.5</version>
</dependency>

<dependency>
  <groupId>com.oracle.jdbc</groupId>
  <artifactId>ojdbc6</artifactId>
  <version>11.2.0.1.0</version>
</dependency>

配置

準備mybatis的配置,在resources目錄下新建一個mybatis-config.xml文件,配置以下session

<?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">
<!-- 根標籤 -->
<configuration>
    <properties>
        <property name="driver" value="oracle.jdbc.driver.OracleDriver" />
        <property name="url" value="jdbc:oracle:thin:@10.60.45.239:1521:devdb" />
        <property name="username" value="fgmain10001" />
        <property name="password" value="test1" />
    </properties>

    <!-- 環境,能夠配置多個,default:指定採用哪一個環境 -->
    <environments default="test">
        <!-- id:惟一標識 -->
        <environment id="test">
            <!-- 事務管理器,JDBC類型的事務管理器 -->
            <transactionManager type="JDBC" />
            <!-- 數據源,池類型的數據源 -->
            <dataSource type="POOLED">
                <property name="driver" value="oracle.jdbc.driver.OracleDriver" />
                <property name="url" value="jdbc:oracle:thin:@10.60.45.239:1521:devdb" />
                <property name="username" value="fgmain10001" />
                <property name="password" value="test1" />
            </dataSource>
        </environment>
        <environment id="development">
            <!-- 事務管理器,JDBC類型的事務管理器 -->
            <transactionManager type="JDBC" />
            <!-- 數據源,池類型的數據源 -->
            <dataSource type="POOLED">
                <property name="driver" value="${driver}" /> <!-- 配置了properties,因此能夠直接引用 -->
                <property name="url" value="${url}" />
                <property name="username" value="${username}" />
                <property name="password" value="${password}" />
            </dataSource>
        </environment>
    </environments>
    <mappers>
        <mapper resource="singleTransMapper.xml" />
    </mappers>
</configuration>

環境配置

<environment id="test">
      <!-- 事務管理器,JDBC類型的事務管理器 -->
      <transactionManager type="JDBC" />
      <!-- 數據源,池類型的數據源 -->
      <dataSource type="POOLED">
          <property name="driver" value="oracle.jdbc.driver.OracleDriver" />
          <property name="url" value="jdbc:oracle:thin:@10.60.45.239:1521:devdb" />
          <property name="username" value="fgmain10001" />
          <property name="password" value="test1" />
      </dataSource>
  </environment>

其中environments能夠配置多個環境的oracle數據源。mybatis

id是環境變量的編號,在<environments>default中能夠設置當前的環境值。
dataSource中設置數據源。類型有3種。包括:POOLED池化,UNPOOLED非池化和JNDI從其餘配置元加載。
driver配置的類名,oracle填寫oracle.jdbc.driver.OracleDriver
url爲配置的數據源,使用239測試庫jdbc:oracle:thin:@10.60.45.239:1521:devdb
username是用戶名。
password是密碼。oracle

配置引用

在value中能夠填寫如${變量名}的配置引用,經過在properties/propertie添加對應的實際的配置值。app

<configuration>
    <properties>
        <property name="driver" value="oracle.jdbc.driver.OracleDriver" />
    </properties>
    
    <environments default="test">
        ...
        <environment id="test">
            ...
            <dataSource type="POOLED">
                <property name="driver" value="${driver}" /> <!-- 配置了properties,因此能夠直接引用 -->
                ...
            </dataSource>
        </environment>
    </environments>
</configuration>

配置映射

配置好數據源後,須要添加對應的表映射,映射包括CRUD對應的SQL語句以及與類之間的映射關係。maven

<configuration>
  ...
    <mappers>
        <mapper resource="singleTransMapper.xml" />
    </mappers>
</configuration>

在resources目錄下新建一個singleTransMapper.xml文件,MyBatis會將singleTransMapper.xml映射到對應的類函數

除了resources之外MyBatis還支持classurlpackage共四種配置測試

class能夠配置具體類名,如com.mybatistest.DAO.SingleTransMapper
url能夠配置完整的文件路徑,如file:///var/mappers/PostMapper.xml
package能夠配置package名稱,註冊全部接口。

查詢

public class SingletransDTO {

    public String EnterpriseNum;

    public String TransNo;

    public String CommandCode;

    public int State;
}

單條件查詢

增長一個查詢單筆的語句,經過輸入流水號,返回查詢到的單筆信息。

<?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="DAO.SingleTransMapper">
    <select id="selectSingle" parameterType="String" resultType="DTO.SingletransDTO">
    select * from se_singletrans where transno = #{transno}
  </select>
</mapper>

namespace須要對應到java中的類,參數和返回類型也須要一致。

在mapper節點下添加select表示select語句
parameterType爲輸入的參數
resultType爲返回的類型,返回類型須要對應java中的類

public interface SingleTransMapper {
    SingletransDTO selectSingle(String transNo);
}
String resource = "mybatis-config.xml";
//加載資源
InputStream inputStream = Resources.getResourceAsStream(resource);
//建立session
SqlSessionFactory sqlSessionFactory = new SqlSessionFactoryBuilder().build(inputStream);
try (SqlSession session = sqlSessionFactory.openSession()) {
  //獲取單筆映射對象
    SingleTransMapper mapper = session.getMapper(SingleTransMapper.class);
    //根據流水號查詢
    SingletransDTO blog = mapper.selectSingle("642EHDCS899XKF8P");

    if(blog != null) {
        System.out.println(blog.ENTERPRISENUM);
        System.out.println(blog.TRANSNO);
        System.out.println(blog.COMMANDCODE);
    }else{
        System.out.println("not found");
    }

}catch (Exception exception)
{
    System.out.println(exception.getMessage());
}

多條件查詢

經過類字段傳遞參數

添加一個查詢配置selectSingleByParam

<?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="DAO.SingleTransMapper">
   
   ...
    <select id="selectSingleByClass" resultType="DTO.SingletransDTO">
    select * from se_singletrans where transno = #{TransNo} and commandCode= #{CommandCode}
  </select>
</mapper>

對應的映射類添加方法對應的方法,MyBatis能夠經過反射將類的字段映射到SQL的參數,須要注意的是類的字段名和sql中配置的大小寫須要一致。

public interface SingleTransMapper {
  ...
  SingletransDTO selectSingleByClass(SingleCondition singleCondition);
}
public class SingleCondition {
    /**
     * 流水號
     */
    public String TransNo;

    /**
     * 指令類型
     */
    public String CommandCode;

    public SingleCondition(String transNo, String commandCode)
    {
        TransNo = transNo;
        CommandCode = commandCode;
    }
}

調用構造函數類的多條件查詢方案

...
SingleTransMapper mapper = session.getMapper(SingleTransMapper.class);
SingletransDTO blog = mapper.selectSingleByClass(new SingleCondition( "642EHDCS899XKF8P","10009"));

經過Map接口傳參

另外一種方案能夠經過傳入HashMap,MayBatis會根據key自動映射到對應的參數。
下面實現經過流水號和指令類型查詢。
添加一個查詢配置selectSingleByMultCondition

<?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="DAO.SingleTransMapper">
    ...
    <select id="selectSingleByMultCondition" resultType="DTO.SingletransDTO">
    select * from se_singletrans where transno = #{transNo} and commandCode= #{commandCode}
  </select>
</mapper>

添加對應的方法,傳入參數爲HashMap<String,Object> param

public interface SingleTransMapper {
  ...
    SingletransDTO selectSingleByMultCondition(HashMap<String,Object> param);
}

修改調用新的多條件查詢方法

...
//獲取單筆映射對象
SingleTransMapper mapper = session.getMapper(SingleTransMapper.class);
//根據流水號查詢
HashMap<String,Object> param = new HashMap<String,Object>();
param.put("transNo","642EHDCS899XKF8P");
param.put("commandCode","10009");
SingletransDTO blog = mapper.selectSingle2(param);
...

須要注意的是,因爲HashMap的key是不區分大小寫的,所以須要和配置文件sql的參數大小寫一致。

Param註解

經過類參數和Map進行多條件查詢都須要建立額外的對象,另外一種比較好的方式能夠經過在方法參數上添加Param註解的方式配置方法參數和SQL參數的映射關係。

添加一個查詢配置selectSingleByParam

<?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="DAO.SingleTransMapper">
   
   ...
    <select id="selectSingleByParam" resultType="DTO.SingletransDTO">
    select * from se_singletrans where transno = #{param1} and commandCode= #{param2}
  </select>
</mapper>

對應的映射類添加方法對應的方法,這樣MyBatis就知道參數映射規則,就會自動映射,須要注意的數參數和sql中配置的大小寫也須要一致。

public interface SingleTransMapper {
    SingletransDTO selectSingle(String transNo);
    SingletransDTO selectSingleByMultCondition(HashMap<String,Object> param);
    SingletransDTO selectSingleByParam(@Param("param1")String transNo, @Param("param2") String commandCode);
}

調用註解傳參方法

...
//獲取單筆映射對象
SingleTransMapper mapper = session.getMapper(SingleTransMapper.class);
SingletransDTO blog = mapper.selectSingleByParam("642EHDCS899XKF8P","10009");
...

插入

在mapper下添加insert表示插入的sql映射。

<?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="DAO.SingleTransMapper">
  
  ...
  <insert id="insert" parameterType="DTO.SingletransDTO">
    insert into se_singletrans(ENTERPRISENUM,TRANSNO,COMMANDCODE,STATE) values(#{EnterpriseNum},#{TransNo},#{CommandCode},#{State})
  </insert>
</mapper>

添加類對應的insert方法

public interface SingleTransMapper {

    ...
    int insert(SingletransDTO singletransDTO);
}

SqlSession默認會開啓事務,在insert完成後須要調用SqlSessioncommit()方法提交事務。

try (SqlSession session = sqlSessionFactory.openSession()) {
    SingleTransMapper mapper = session.getMapper(SingleTransMapper.class);
    SingletransDTO singletransDTO = new     SingletransDTO();
    singletransDTO.EnterpriseNum  = "QT330001";
    singletransDTO.TransNo = "MYBATIS.INSERT";
    singletransDTO.CommandCode = "10009";
    int count = mapper.insert(singletransDTO);
    session.commit();
    System.out.println("insert result:" +count);
}catch (Exception exception)
{
    System.out.println(exception.getMessage());
}

咱們也能夠調用SqlSession openSession(boolean autoCommit)傳入參數,自動提交。

更新

在mapper下添加update節點表示插入,插入時能夠對插入的字段設置條件,達成某條件是該字段才須要更新。

<?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="DAO.SingleTransMapper">
  
  ...
   <update id="update" parameterType="DTO.SingletransDTO">
    update se_singletrans
    <set>
        <if test="State != null and State!=''"></if>
        STATE=#{State}
    </set>
    where transno = #{TransNo} and commandCode= #{CommandCode}
  </update>
</mapper>

添加類對應的update方法

public interface SingleTransMapper {

    ...
    int update(SingletransDTO singletransDTO);
}

SqlSession默認會開啓事務,和insert同樣,在update完成後須要調用SqlSessioncommit()方法提交事務。

try (SqlSession session = sqlSessionFactory.openSession()) {
    SingleTransMapper mapper = session.getMapper(SingleTransMapper.class);
    SingletransDTO singletransDTO = new SingletransDTO();
    singletransDTO.EnterpriseNum = "QT330001";
    singletransDTO.TransNo = "MYBATIS.INSERT";
    singletransDTO.CommandCode = "10009";
    singletransDTO.State = 2;
    int count = mapper.update(singletransDTO);
    session.commit();
    System.out.println("update result:" +count);
}catch (Exception exception)
{
    System.out.println(exception.getMessage());
}

刪除

在mapper下添加delete節點表示刪除。

<?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="DAO.SingleTransMapper">
  
  ...
   
  <delete id="delete">
    delete from se_singletrans where transno = #{TransNo} and commandCode= #{CommandCode}
  </delete>
</mapper>

添加類對應的delete方法,能夠經過參數註解的方式指定參數。

public interface SingleTransMapper {

    ...
    int delete(@Param("TransNo")String transNo, @Param("CommandCode") String commandCode);
}

SqlSession默認會開啓事務,在delete完成後須要調用SqlSessioncommit()方法提交事務。

try (SqlSession session = sqlSessionFactory.openSession()) {
    SingleTransMapper mapper = session.getMapper(SingleTransMapper.class);
    int count = mapper.delete("MYBATIS.INSERT","10009");
    session.commit();
    System.out.println("delete result:" +count);
}catch (Exception exception)
{
    System.out.println(exception.getMessage());
}

字段映射

若字段名和數據庫的字段名不一致,能夠經過配置進行映射。添加resultMap節點,配置類字段和數據庫字段的映射關係,若沒有配置的字段,則根據默認MyBatis的映射關係處理,即字段名同樣的自動映射,MyBatis會嘗試進行類型轉換,若轉換異常,則可能拋錯。咱們也能夠經過typeHandler自定義本身的類型處理器。

<?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="DAO.SingleTransMapper">

  <resultMap id="singleResultMap" type="DTO.SingletransDTO">
    <result property="TransNo"  column="transNo" />
    <result property="CommandCode" column="commandCode"/>
    <result property="SpecialProperty" typeHandler="CustomTypeHandle" column="SpecialColumn"/>
  </resultMap>
  <select id="selectSingleToReusltMap" resultMap="singleResultMap">
    select * from se_singletrans where transno = #{param1} and commandCode= #{param2}
  </select>
</mapper>

關於TypeHandle這裏不作具體闡述,有興趣的能夠看下MyBatis自定義類型處理器 TypeHandler

參考文獻

  1. Maven添加Oracle的依賴及驅動
  2. MyBatis自定義類型處理器 TypeHandler
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