Xelem is a compact Java-library to read and write Excel files of type SpreadsheetML. It can produce sophisticated, intricate and complex spreadsheets from within any Java program. And, since the release of xelem.2.0, it can readxml-spreadsheets.
PythonOffice is a Python API for the Ms XML (Excel) Spreadsheet format. It allows you to read and write Excel XML documents from within the Python programming language. In future, support for other formats is planned, including OOo, Ms Open Xml.