关于hibernate的一些小记

时间  2019-11-12
标签 关于 hibernate 些小 栏目 Hibernate 繁體版
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最近接触的老项目，老是爱用hibernate，维护起来以为很麻烦，这里随便总结一下hibernate的特色。java

首先：sql

1.hibernate能够直接对java实例操做，达到数据库的增删改查做用，可是这个实例，只对应一个表。数据库

2.hibernate能够经过编写hql语句，达成自定义SQL查询，可是返回结果，多是一个map，而没法直接对应成JAVA实例，要本身组装查询结果。mybatis

3.hibernate能够经过建立配置文件，配置文件里，定义一个复杂的JAVA实例Class，对应数据库中一个复杂的视图table，并指定在这个复杂视图中，多个表之间的one-to-one, one-to-many, many-to-many关系，和指定哪一个字段做为关联条件。而在复杂的java实例中，根据一对一仍是一对多的关系，建立其余表的实例做为成员变量，接收其余表的查询结果。既查询一次这个复杂的java实例，就等于关联查询了好多张表。app

该文件的命名，通常以XXXX.hbm.xml结尾。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基于JPA，经过注解的方式，来完成数据库的增删改查。使用这个方式，类的成员属性，都须要加上注解，标识这个成员属性，对应表的哪一个字段，是不是主键，是不是关联条件。一样的，实体类新增了成员变量，而改变量不对应表的字段时，也要加上注解，标识该字段与表无关。fetch

在多表关联查询的时候，父类查询结果，持有子类查询结果时，还要在父类中还须要持有子查询类的实体类对象，并添加注解，标识改子查询是one-to-one仍是one-to-many类型，若是是one-to-many，就须要持有子表实体类的集合做为成员变量。.net

 

以上，是我在项目中，遇到的hibernate几种用法。hibernate

下面，咱们来讲一下mybatis，实际上mybatis主要有两种用法：code

1.基于注解的，在dao文件中，定义SQL方法，而在每一个自定义的SQL方法上，编写mybatis的注解，来对数据库进行操做。可是缺点是多表关联查询，须要编写的SQL比较复杂，使用注解的方式，会更复杂。因此咱们通常不用。

2.基于配置文件，基于配置文件的mybatis用法比较常见，有点是，适合编写复杂，超长的sql语句，并且配套的动态sql子句，用起来很好用。

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