导出150万的数据，用sql分页导出，每页数据1000条，数据库用postgresql
问题：
不停的分页取出数据之后，在某一段时间内，出现了传送数据至后端时发生 I/O 错误错误
发现错误信息如下：
Caused by: java.net.SocketException: Socket closed
at java.net.SocketInputStream.socketRead0(Native Method)
at java.net.SocketInputStream.socketRead(SocketInputStream.java:116)
at java.net.SocketInputStream.read(SocketInputStream.java:170)
at java.net.SocketInputStream.read(SocketInputStream.java:141)
at org.postgresql.core.VisibleBufferedInputStream.readMore(VisibleBufferedInputStream.java:145)
at org.postgresql.core.VisibleBufferedInputStream.ensureBytes(VisibleBufferedInputStream.java:114)
at org.postgresql.core.VisibleBufferedInputStream.read(VisibleBufferedInputStream.java:73)
at org.postgresql.core.PGStream.ReceiveChar(PGStream.java:274)
at org.postgresql.core.v3.QueryExecutorImpl.processResults(QueryExecutorImpl.java:1660)
at org.postgresql.core.v3.QueryExecutorImpl.execute(QueryExecutorImpl.java:257)
... 95 more
socke没有取字节流完成前，直接关闭了，这个具体是什么原因？
