關於hibernate的一些小記

時間  2019-11-12
標籤 關於 hibernate 些小 欄目 Hibernate 简体版
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最近接觸的老項目，老是愛用hibernate，維護起來以爲很麻煩，這裏隨便總結一下hibernate的特色。java

首先：sql

1.hibernate能夠直接對java實例操做，達到數據庫的增刪改查做用，可是這個實例，只對應一個表。數據庫

2.hibernate能夠經過編寫hql語句，達成自定義SQL查詢，可是返回結果，多是一個map，而沒法直接對應成JAVA實例，要本身組裝查詢結果。mybatis

3.hibernate能夠經過建立配置文件，配置文件裏，定義一個複雜的JAVA實例Class，對應數據庫中一個複雜的視圖table，並指定在這個複雜視圖中，多個表之間的one-to-one, one-to-many, many-to-many關係，和指定哪一個字段做爲關聯條件。而在複雜的java實例中，根據一對一仍是一對多的關係，建立其餘表的實例做爲成員變量，接收其餘表的查詢結果。既查詢一次這個複雜的java實例，就等於關聯查詢了好多張表。app

該文件的命名，通常以XXXX.hbm.xml結尾。ide

<?xml version="1.0" encoding="utf-8"?>
<!DOCTYPE hibernate-mapping PUBLIC "-//Hibernate/Hibernate Mapping DTD 3.0//EN"
"http://hibernate.sourceforge.net/hibernate-mapping-3.0.dtd">

<hibernate-mapping auto-import="false">
    <class name="com.nstc.cpm.biz.acm.Account" table="V_CPM_BKUNIT_ACCOUNT" lazy="true">
        <id name="id" type="java.lang.Integer">
            <column name="ACCOUNT_ID" />
            <generator class="sequence">
            	<param name="sequence">S_CPM_BOOK_UNIT</param>
            </generator>
        </id>
        <discriminator column="ACC_CLASS" />
        <version name="version" type="java.lang.Integer">
        	<column name="VERSION_COLUMN" />
        </version>
        <many-to-one name="customer" class="com.nstc.cpm.biz.acm.Customer" fetch="join" outer-join="true">
            	<column name="CUST_ID" />
       	</many-to-one>
        <many-to-one name="subject" class="com.nstc.cpm.biz.acm.Subject" fetch="join">
            <column name="SUBJECT_ID" length="8" not-null="true" />
        </many-to-one>
		<many-to-one name="currency" class="com.nstc.cpm.biz.model.BCurrency"
			fetch="select" update="false" insert="false">
			<column name="CUR_CODE" 
				not-null="true" />
		</many-to-one>
        <property name="number" type="java.lang.String" unique="true">
            <column name="ACCOUNT_NO" length="32" not-null="true" />
        </property>
        <one-to-one name="accIntr"  class="com.nstc.cpm.biz.acm.DefaultAccIntr" property-ref="accountId"/>
		<many-to-one name="type" class="com.nstc.cpm.biz.acm.AccountType" fetch="select" not-null="true">
            <column name="TYPE_ID" length="8" />
        </many-to-one>
        <many-to-one name="bizType" class="com.nstc.cpm.biz.model.BizType" fetch="select">
            <column name="BTY_ID" length="6" />
        </many-to-one>
        <many-to-one name="smartBizType" class="com.nstc.cpm.biz.model.SmartBizType" fetch="select">
            <column name="SMART_BTY_ID" />
        </many-to-one>
        <property name="name" type="java.lang.String">
            <column name="ACCOUNT_NAME" length="128" />
        </property>
        <property name="openDate" type="java.util.Date">
            <column name="OPEN_DATE" length="7" />
        </property>
        <property name="endDate" type="java.util.Date">
            <column name="END_DATE" length="7" />
        </property>
        <property name="interBranchFlag" type="java.lang.Integer">
            <column name="INTER_BRANCH_FLAG"  />
        </property>

        <property name="currencyNo" type="java.lang.String">
            <column name="CUR_CODE" length="32" not-null="true" />
        </property>
        <!-- MODIFY BY ZHUQW FOR ZMJT-388 START 20170815 -->
        <many-to-one name="branch" class="com.nstc.cpm.biz.model.Branch" fetch="join">
            <column name="BRANCH_NO" length="8" not-null="true" />
        </many-to-one>
        <!-- MODIFY BY ZHUQW FOR ZMJT-388 END 20170815 -->
        <property name="balanceDir" type="java.lang.Integer">
            <column name="BALANCE_DIR"  />
        </property>
        <property name="state" type="java.lang.Integer">
            <column name="ACCOUNT_STATE"  />
        </property>
        <property name="clearDate" type="java.util.Date">
            <column name="CLEAR_DATE"/>
        </property>
        <property name="floorAmount" type="java.lang.Double">
            <column name="FLOOR_AMOUNT" />
        </property>

        <property name="sourceId" type="java.lang.String">
            <column name="SOURCE_MARK" length="32" />
        </property>
        <property name="thirdCustomerId" type="java.lang.Integer">
            <column name="THIRD_CUSTOM_ID"  />
        </property>
        <property name="initBalance" type="java.lang.Double">
            <column name="INIT_BALANCE"/>
        </property>
		<property name="sleepState" type="java.lang.Integer">
			<column name="SLEEP_STATE"/>
		</property>
		<property name="accTxDate" type="java.util.Date">
			<column name="ACCOUNT_TX_DATE"/>
		</property>
		<property name="sleepSDate" type="java.util.Date">
			<column name="SLEEP_SDATE"/>
		</property>
		
		<property name="sleepEDate" type="java.util.Date">
			<column name="SLEEP_EDATE"/>
		</property>
        <set name="intrSbUnits" inverse="true">
            <key>
                <column name="CPM_ACCOUNT_ID" not-null="true" />
            </key>
            <one-to-many class="com.nstc.cpm.biz.acm.StandingBookUnit" />
        </set>

		<subclass name="com.nstc.cpm.biz.acm.CustomerAccount" discriminator-value="CustomerAccount">
       		<subclass name="com.nstc.cpm.biz.acm.EntitySettlementAccount" discriminator-value="EntitySettlementAccount">
       			<subclass name="com.nstc.cpm.biz.acm.DemandDepositAccount" discriminator-value="DemandDepositAccount">
       				<sql-delete>
		     			delete from CPM_BOOK_UNIT a where a.ACCOUNT_ID=? AND A.VERSION_COLUMN = ?
					</sql-delete>
				</subclass>
				<sql-delete>
		     		delete from CPM_BOOK_UNIT a where a.ACCOUNT_ID=? AND A.VERSION_COLUMN = ?
				</sql-delete>
			</subclass>

			<subclass name="com.nstc.cpm.biz.acm.VirtualSettlementAccount" discriminator-value="VirtualSettlementAccount">
				<subclass name="com.nstc.cpm.biz.acm.CustLinkageAccount" discriminator-value="CustLinkageAccount">
					<sql-delete>
		     			delete from CPM_BOOK_UNIT a where a.ACCOUNT_ID=? AND A.VERSION_COLUMN = ?
					</sql-delete>
				</subclass>
				<sql-delete>
		     		delete from CPM_BOOK_UNIT a where a.ACCOUNT_ID=? AND A.VERSION_COLUMN = ?
				</sql-delete>
			</subclass>

			<subclass name="com.nstc.cpm.biz.acm.DepositAccount" discriminator-value="DepositAccount">
				<subclass name="com.nstc.cpm.biz.acm.FixedDepositAccount" discriminator-value="FixedDepositAccount">
					<sql-delete>
		     			delete from CPM_BOOK_UNIT a where a.ACCOUNT_ID=? AND A.VERSION_COLUMN = ?
					</sql-delete>
				</subclass>
				<subclass name="com.nstc.cpm.biz.acm.CallDepositAccount" discriminator-value="CallDepositAccount">
					<sql-delete>
		     			delete from CPM_BOOK_UNIT a where a.ACCOUNT_ID=? AND A.VERSION_COLUMN = ?
					</sql-delete>
				</subclass>
				<subclass name="com.nstc.cpm.biz.acm.MarginDepositAccount" discriminator-value="MarginDepositAccount">
					<subclass name="com.nstc.cpm.biz.acm.MarginDemandDepositAccount" discriminator-value="MarginDemandDepositAccount">
						<sql-delete>
			     			delete from CPM_BOOK_UNIT a where a.ACCOUNT_ID=? AND A.VERSION_COLUMN = ?
						</sql-delete>
					</subclass>
					<subclass name="com.nstc.cpm.biz.acm.MarginFixedDepositAccount" discriminator-value="MarginFixedDepositAccount">
						<sql-delete>
			     			delete from CPM_BOOK_UNIT a where a.ACCOUNT_ID=? AND A.VERSION_COLUMN = ?
						</sql-delete>
					</subclass>
					<sql-delete>
		     			delete from CPM_BOOK_UNIT a where a.ACCOUNT_ID=? AND A.VERSION_COLUMN = ?
					</sql-delete>
				</subclass>
				<sql-delete>
		     		delete from CPM_BOOK_UNIT a where a.ACCOUNT_ID=? AND A.VERSION_COLUMN = ?
				</sql-delete>
			</subclass>

			<subclass name="com.nstc.cpm.biz.acm.LoanAccount" discriminator-value="LoanAccount">
				<subclass name="com.nstc.cpm.biz.acm.CommonLoanAccount" discriminator-value="CommonLoanAccount">
					<sql-delete>
		     			delete from CPM_BOOK_UNIT a where a.ACCOUNT_ID=? AND A.VERSION_COLUMN = ?
					</sql-delete>
				</subclass>
				<subclass name="com.nstc.cpm.biz.acm.SyndicatedLoanAccount" discriminator-value="SyndicatedLoanAccount">
					<sql-delete>
		     			delete from CPM_BOOK_UNIT a where a.ACCOUNT_ID=? AND A.VERSION_COLUMN = ?
					</sql-delete>
				</subclass>
				<subclass name="com.nstc.cpm.biz.acm.BankAccount" discriminator-value="BankAccount">
					<sql-delete>
		     			delete from CPM_BOOK_UNIT a where a.ACCOUNT_ID=? AND A.VERSION_COLUMN = ?
					</sql-delete>
				</subclass>
				<sql-delete>
		     		delete from CPM_BOOK_UNIT a where a.ACCOUNT_ID=? AND A.VERSION_COLUMN = ?
				</sql-delete>
			</subclass>
			<sql-delete>
		     	delete from CPM_BOOK_UNIT a where a.ACCOUNT_ID=? AND A.VERSION_COLUMN = ?
			</sql-delete>
		</subclass>

		<subclass name="com.nstc.cpm.biz.acm.InsideAccountingAccount" discriminator-value="InsideAccountingAccount">
			<sql-delete>
		     	delete from CPM_BOOK_UNIT a where a.ACCOUNT_ID=? AND A.VERSION_COLUMN = ?
			</sql-delete>
		</subclass>

		<subclass name="com.nstc.cpm.biz.acm.OffSheetAccountingAccount" discriminator-value="OffSheetAccountingAccount">
			<sql-delete>
		     	delete from CPM_BOOK_UNIT a where a.ACCOUNT_ID=? AND A.VERSION_COLUMN = ?
			</sql-delete>
		</subclass>

		<sql-delete>
		     delete from CPM_BOOK_UNIT a where a.ACCOUNT_ID=? AND A.VERSION_COLUMN = ?
		</sql-delete>
    </class>
</hibernate-mapping>

4.hibernate基於JPA，經過註解的方式，來完成數據庫的增刪改查。使用這個方式，類的成員屬性，都須要加上註解，標識這個成員屬性，對應表的哪一個字段，是不是主鍵，是不是關聯條件。一樣的，實體類新增了成員變量，而改變量不對應表的字段時，也要加上註解，標識該字段與表無關。fetch

在多表關聯查詢的時候，父類查詢結果，持有子類查詢結果時，還要在父類中還須要持有子查詢類的實體類對象，並添加註解，標識改子查詢是one-to-one仍是one-to-many類型，若是是one-to-many，就須要持有子表實體類的集合做爲成員變量。.net

 

以上，是我在項目中，遇到的hibernate幾種用法。hibernate

下面，咱們來講一下mybatis，實際上mybatis主要有兩種用法：code

1.基於註解的，在dao文件中，定義SQL方法，而在每一個自定義的SQL方法上，編寫mybatis的註解，來對數據庫進行操做。可是缺點是多表關聯查詢，須要編寫的SQL比較複雜，使用註解的方式，會更復雜。因此咱們通常不用。

2.基於配置文件，基於配置文件的mybatis用法比較常見，有點是，適合編寫複雜，超長的sql語句，並且配套的動態sql子句，用起來很好用。

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