Hi POI users, I am trying to read an excel file from a java program. For first 10 times it worked fine but later it started giving InvalidHeaderSignature Error. java.io.IOException: Invalid header signature; read 7521418675403179042, expected -2226271756974174256 15:32:25,274 INFO [STDOUT] at org.apache.poi.poifs.storage.HeaderBlockReader.<init>(HeaderBlockReader.j ava:88) 15:32:25,274 INFO [STDOUT] at org.apache.poi.poifs.filesystem.POIFSFileSystem.<init>(POIFSFileSystem.ja va:83) By searching in poi archives, I got to know that many users got the same problem but no where I could find the solution. I understand that it is not a properly saved excel file. But this is the file we are going to receive from customers. Every time we can not open the file and copy the contents. Is there any way we can solve this problem? One more problem I am facing is, when I am reading a cell, the data inside the cell is 3732135467(phone no) but excel displays it as 3.7+e9 when I am trying to read it, POI getCell() Displays it as 3.732135467+e9 . Is there a way to display the correct data? Thanks nmadhava
"Invalid Header Signature" means the file stream is incorrect.. either the file is corrupt, or is not a xl file. So poi cant help here. Please check upstream.