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想在java中动态的创建hibernate的配置文件（并不是生成而是创建hibernate配置文件对象），脑海中第一个想到的就是spring源码，因为spring有整合hibernate的功能，于是翻阅了spring的代码一看，果然很简单。下面先发断简单的demo。
public static void main(String[] args) throws Exception {
Configuration configuration = new Configuration();
Properties properties = new Properties();
properties.setProperty("hibernate.dialect",
"org.hibernate.dialect.SQLServerDialect");
String[] mappingResources = new String[1];
mappingResources[0] = "com/syj/domain/Issue.hbm.xml";
for (int i = 0; i < mappingResources.length; i++) {
Resource resource = new ClassPathResource(mappingResources[i]
.trim(), Thread.currentThread().getContextClassLoader());
configuration.addInputStream(resource.getInputStream());
}
configuration.addProperties(properties);
configuration.buildSessionFactory();
}
上面代码中properties还缺少很多属性，因为只是个demo所以我没有填写全部的属性，其实这里的属性就是指hibernate.cfg.xml中那些属性，例如hibernate.connection.provider_class，show_sql等等。添加到properties中就可以了。
为什么想到spring的源码呢，下面来看spring中如何整合的
<bean id="sessionFactory"
class="org.springframework.orm.hibernate3.LocalSessionFactoryBean">
<property name="dataSource">
<ref bean="dataSource" />
</property>
<property name="hibernateProperties">
<props>
<prop key="hibernate.dialect">org.hibernate.dialect.SQLServerDialect</prop>
<prop key="hibernate.show_sql">false</prop>
<prop key="hibernate.format_sql">false</prop>
<prop key="hibernate.use_sql_comments">false</prop>
<!-- 为单向关联(一对一, 多对一)的外连接抓取（outer join fetch）树设置最大深度. 值为0意味着将关闭默认的外连接抓取 -->
<prop key="hibernate.max_fetch_depth">3</prop>
<!-- 为Hibernate关联的批量抓取设置默认数量 -->
<prop key="hibernate.default_batch_fetch_size">8</prop>
<!-- 强制Hibernate按照被更新数据的主键，为SQL更新排序。这么做将减少在高并发系统中事务的死锁。 -->
<prop key="hibernate.order_updates">true</prop>
<!-- session在事务完成后将被自动清洗(flush) -->
<prop key="hibernate.transaction.flush_before_completion">true</prop>
<!-- Oracle限制那些通过JDBC驱动传输的字节数组的数目. 如果你希望使用二进值 (binary)或 可序列化的 (serializable)类型的大对象, 你应该开启 hibernate.jdbc.use_streams_for_binary属性. -->
<prop key="hibernate.bytecode.use_reflection_optimizer">true</prop>
</props>
</property>
<property name="mappingResources">
<list>
<value>com/xxx/domain/xxx.hbm.xml</value>
</list>
</property>
</bean>
大家都知道spring的依赖注入，其实依赖注入很简单这里不做此介绍，我们按照spring的注入流程思考就可以了，下面看看spring优雅的实现把。在这里我们只关注LocalSessionFactoryBean的一个方法：protected SessionFactory buildSessionFactory() throws Exception {
// Create Configuration instance.
Configuration config = newConfiguration();
DataSource dataSource = getDataSource();
if (dataSource != null) {
// Make given DataSource available for SessionFactory configuration.
configTimeDataSourceHolder.set(dataSource);
}
if (this.jtaTransactionManager != null) {
// Make Spring-provided JTA TransactionManager available.
configTimeTransactionManagerHolder.set(this.jtaTransactionManager);
}
if (this.lobHandler != null) {
// Make given LobHandler available for SessionFactory configuration.
// Do early because because mapping resource might refer to custom types.
configTimeLobHandlerHolder.set(this.lobHandler);
}
// Analogous to Hibernate EntityManager's Ejb3Configuration:
// Hibernate doesn't allow setting the bean ClassLoader explicitly,
// so we need to expose it as thread context ClassLoader accordingly.
Thread currentThread = Thread.currentThread();
ClassLoader threadContextClassLoader = currentThread.getContextClassLoader();
boolean overrideClassLoader =
(this.beanClassLoader != null && !this.beanClassLoader.equals(threadContextClassLoader));
if (overrideClassLoader) {
currentThread.setContextClassLoader(this.beanClassLoader);
}
try {
if (this.jtaTransactionManager != null) {
// Set Spring-provided JTA TransactionManager as Hibernate property.
config.setProperty(
Environment.TRANSACTION_MANAGER_STRATEGY, LocalTransactionManagerLookup.class.getName());
config.setProperty(
Environment.TRANSACTION_STRATEGY, JTATransactionFactory.class.getName());
}
else {
// Set connection release mode "on_close" as default.
// This was the case for Hibernate 3.0; Hibernate 3.1 changed
// it to "auto" (i.e. "after_statement" or "after_transaction").
// However, for Spring's resource management (in particular for
// HibernateTransactionManager), "on_close" is the better default.
config.setProperty(Environment.RELEASE_CONNECTIONS, ConnectionReleaseMode.ON_CLOSE.toString());
}
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