RequestgetPart

RequestgetPart is a programming construct used to extract a specific component from a multipart HTTP request within a web application. It is commonly used to process form submissions that include file uploads, where the request body is divided into parts by name.

In the Java Servlet API, the equivalent capability is provided by the HttpServletRequest.getPart(String name) method (along with getParts()). These methods operate on requests with a multipart/form-data content type and require the target servlet to be configured with multipart support, typically via the @MultipartConfig annotation or web.xml settings.

Calling getPart with a form field name returns a Part object that represents the corresponding piece of the request. The method may return null if no part with that name exists and can throw exceptions such as ServletException or IOException if the request is not multipart or if I/O errors occur. A Part provides access to the input stream, content type, size, and the submitted file name, and it can be saved to disk by using its write method.

Typical usage involves retrieving the file part for an input named, for example, "upload," reading or validating its contents, and persisting it as needed. Developers should validate content types and sizes and ensure proper cleanup of streams after use.

Related concepts include request.getParts() for enumerating all parts and, in other frameworks, middleware or helpers that handle multipart form data and file uploads.