如何在休眠狀態下獲取遠程端數據庫的數據

Question

我開發了一個應用程序報告工具。
我必須連接多個遠程端數據庫及其憑據並獲取數據庫值。
我該怎麼做？
這是我的Hibernate配置文件

<hibernate-configuration> 
    <session-factory> 

    <property name="hibernate.dialect">org.hibernate.dialect.MySQL5InnoDBDialect</property> 
    <property name="dialect">org.hibernate.dialect.MySQLDialect</property> 

    <property name="show_sql">true</property> 
    <property name="hibernate.hbm2ddl.auto">update</property> 

    <property name="hibernate.connection.SetBigStringTryClob">true</property> 

    <property name="hibernate.jdbc.batch_size">0</property> 

    </session-factory> 
</hibernate-configuration> 

Answer 1

用於連接多個數據庫編寫一個會話工廠不好。所以如果你想連接多少個數據庫來寫入多個配置文件是最好的方式。例如假設，我想連接oracle，mysql數據庫。所以我可以做的是我會爲oracle寫一個配置文件，例如oracle-configuration.cfg.xml對於mysql我將創建mysql-configuration.cfg。xml

現在你的問題與遠程數據庫連接，你需要給遠程地址的憑據。

例如，我的遠程數據庫地址是192.168.0.14。現在我要連接Oracle數據庫 現在的連接性能，如

甲骨文configuration.cfg.xml

<?xml version="1.0" encoding="UTF-8"?> 

<!DOCTYPE hibernate-configuration PUBLIC 
"-//Hibernate/Hibernate Configuration DTD 3.0//EN" 
"http://www.hibernate.org/dtd/hibernate-configuration-3.0.dtd"> 

<hibernate-configuration> 
<session-factory> 
<!-- Database connection settings --> 
<property name="connection.driver_class">oracle.jdbc.driver.OracleDriver</property> 
<property name="connection.username">ranga</property> 
<property name="connection.password">ranga</property> 
<property name="connection.url">jdbc:oracle:thin:@192.168.0.14:1521:XE</property> 

<!-- JDBC connection pool (use the built-in) --> 
<property name="connection.pool_size">1</property> 

<!-- SQL dialect --> 
<property name="dialect">org.hibernate.dialect.Oracle10gDialect</property> 

<!-- Disable the second-level cache --> 
<property name="cache.provider_class">org.hibernate.cache.NoCacheProvider</property> 

<!-- Echo all executed SQL to stdout --> 
<property name="show_sql">true</property> 

<!-- Drop and re-create the database schema on startup --> 
<property name="hbm2ddl.auto">create</property> 

<mapping resource="com/ranga/mapping/Persom.hbm.xml"/> 

</session-factory> 
</hibernate-configuration>

Answer 2

你應該有單獨的會話工廠和數據源配置爲每個DBS的，你可以通過數據源名稱指的是正確的e.g。

這意味着如果你有3個遠程數據庫，那麼理想情況下你應該有3個sessionFacories和數據源。

例子：

休眠-first.cfg.xml - 你一樣有

<hibernate-configuration> 
    <session-factory> 

    <property name="hibernate.dialect">org.hibernate.dialect.MySQL5InnoDBDialect</property> 
    <property name="dialect">org.hibernate.dialect.MySQLDialect</property> 

    <property name="show_sql">true</property> 
    <property name="hibernate.hbm2ddl.auto">update</property> 

    <property name="hibernate.connection.SetBigStringTryClob">true</property> 

    <property name="hibernate.jdbc.batch_size">0</property> 

    <!-- Here commes the entities mapped to tables in the FIRST database --> 
    <mapping class="com.yourpackage.EntityOftheFirstDatabase" /> 

    </session-factory> 

休眠-second.cfg.xml

<hibernate-configuration> 
    <session-factory> 

    <property name="hibernate.dialect">org.hibernate.dialect.MySQL5InnoDBDialect</property> 
    <property name="dialect">org.hibernate.dialect.MySQLDialect</property> 

    <property name="show_sql">true</property> 
    <property name="hibernate.hbm2ddl.auto">update</property> 

    <property name="hibernate.connection.SetBigStringTryClob">true</property> 

    <property name="hibernate.jdbc.batch_size">0</property> 

    <!-- Here commes the entities mapped to tables in the SECOND database --> 
    <mapping class="com.yourpackage.EntityOftheSecondDatabase" /> 

    </session-factory> 

現在讓我們來配置會話工廠春天：

<!-- Hibernate SessionFactory for the FIRST database --> 
    <bean id="sessionFactoryForTheFirstDatabase" class="org.springframework.orm.hibernate4.LocalSessionFactoryBean"> 
     <property name="dataSource" ref="dataSourceForTheFirstDatabase" /> 
     <property name="configLocation" value="classpath:hibernate-first.cfg.xml" /> 
    </bean> 



<!-- Hibernate SessionFactory for the SECOND database --> 
     <bean id="sessionFactoryForTheSecondDatabase" class="org.springframework.orm.hibernate4.LocalSessionFactoryBean"> 
      <property name="dataSource" ref="dataSourceForTheSecondDatabase" /> 
      <property name="configLocation" value="classpath:hibernate-second.cfg.xml" /> 
     </bean> 

數據源

<bean id="dataSourceForTheFirstDatabase" class="org.springframework.jdbc.datasource.DriverManagerDataSource"> 
     <property name="driverClassName" value="your specific" /> 
     <property name="url" value="${database.url}" /> 
     <property name="username" value="${database.username}" /> 
     <property name="password" value="${database.password}" /> 
    </bean> 

第二個數據源是非常相同的只需將它指向第二個數據庫。如果你想配置TX管理比你需要兩個事務管理器爲您databses：

<bean id="firstDbServiceProxyCreator" class="org.springframework.aop.framework.autoproxy.BeanNameAutoProxyCreator"> 
     <description>Transaction boundaries are mapped to service layer</description> 
     <property name="proxyTargetClass" value="false" /> 
     <property name="beanNames"> 
      <list> 
     <value>ServicesMangingoperationsAboveYourFirstDatabase1</value> 
     <value>ServicesMangingoperationsAboveYourFirstDatabase2</value> 
      </list> 
     </property> 
     <property name="interceptorNames"> 
      <list> 
      <value>FirstDbTxInterceptor</value> 
      </list> 
     </property> 
    </bean> 

如果你想有一個交易是跨越多個數據庫的也有可能，只是不知道你是否需要它！希望這對你來說已經足夠清晰。我知道有更多奇特的方法來定義TX經理和春天的東西，主要是如果你使用的是最新的，我建議你試一試，就像我描述的那樣，之後你可以調整它 - 谷歌是你的朋友:)