如何获取 java.sql.ResultSet 的大小？

请改为执行查询。SELECT COUNT(*) FROM ...

或

int size =0;
if (rs != null) 
{
  rs.last();    // moves cursor to the last row
  size = rs.getRow(); // get row id 
}

在任何一种情况下，您都不必遍历整个数据。

ResultSet rs = ps.executeQuery();
int rowcount = 0;
if (rs.last()) {
  rowcount = rs.getRow();
  rs.beforeFirst(); // not rs.first() because the rs.next() below will move on, missing the first element
}
while (rs.next()) {
  // do your standard per row stuff
}