批量插入(Batch inserts)
如果要将很多对象持久化,你必须通过经常的调用 flush() 以及稍后调用 clear() 来控制第一级缓存的大小。
Session session = sessionFactory.openSession();
Transaction tx = session.beginTransaction();
for ( int i=0; i<100000; i++ ) {
Customer customer = new Customer(.....);
session.save(customer);
if ( i % 20 == 0 ) { //20, same as the JDBC batch size
//flush a batch of inserts and release memory:
session.flush();
session.clear();
}
}
tx.commit();
session.close();
此方法同样适用于检索和更新数据。此外,在进行会返回很多行数据的查询时,你需要使用 scroll() 方法以便充分利用服务器端游标所带来的好处。
Session session = sessionFactory.openSession();
Transaction tx = session.beginTransaction();
ScrollableResults customers = session.getNamedQuery("GetCustomers")
.setCacheMode(CacheMode.IGNORE)
.scroll(ScrollMode.FORWARD_ONLY);
int count=0;
while ( customers.next() ) {
Customer customer = (Customer) customers.get(0);
customer.updateStuff(...);
if ( ++count % 20 == 0 ) {
//flush a batch of updates and release memory:
session.flush();
session.clear();
}
}
tx.commit();
session.close();
hibernate 批量插入及修改
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转载自wowo12345.iteye.com/blog/1617259
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