Question

我正在使用for循环（百万计数）在运行时生成一些数据。我喜欢将它作为单行blob保存到PostgreSQL DB中，因为在变量中保存所有字符串将占用更多RAM。我怎样才能在java中实现这一点。

我的期望是：

 Open PostgreSQL connection
 For loop
  continuously save data to DB as blob
 End loop
 Close Connection

Answer 1

请参阅PostgreSQL JDBC文档的Chapter 7. Storing Binary Data。他们LargeObject的示例似乎正是您所寻找的：

// All LargeObject API calls must be within a transaction block
conn.setAutoCommit(false);

// Get the Large Object Manager to perform operations with
LargeObjectManager lobj = ((org.postgresql.PGConnection)conn).getLargeObjectAPI();

// Create a new large object
int oid = lobj.create(LargeObjectManager.READ | LargeObjectManager.WRITE);

// Later you will be able to access data loading it by `oid` identifier.
// Or you can save it's value to some row in database

// Open the large object for writing
LargeObject obj = lobj.open(oid, LargeObjectManager.WRITE);

// Do your job here and stream the content
// Multiple obj.write calls expected

// Close the large object
obj.close();

// Finally, commit the transaction.
conn.commit();

但通常使用这种方法没什么意义。将数据附加到本地文件（临时？）是一种更有效的方法。

如何在java中将运行时生成的字符串写入postgresql blob

1 个答案: