What is the Meaning and Usage of ServletContext.getRealPath('/')?

ServletContext.getRealPath("/") Meaning and Usage

Introduction

In Servlet programming, ServletContext.getRealPath() converts a web content path (the path in the expanded WAR folder structure) to an absolute disk file system path.

Use of '/' in getRealPath()

The "/" passed to getRealPath() represents the web content root, or the directory where all web-accessible content is located. It's the equivalent of the /web folder in the following project structure:

YourWebProject
|-- src
|-- web
     |-- META-INF
     |-- WEB-INF
     |-- index.jsp
     |-- login.jsp

Usage Scenarios

When should you use getRealPath("/")?

• No sensible use cases: Avoid using getRealPath() in most scenarios. There are more portable and reliable alternatives.

Alternatives to getRealPath()

• Reading web resources: Use ServletContext.getResourceAsStream() instead for an input stream of the resource.
• Listing web resources: Use ServletContext.getResourcePaths() for a list of all available web resource paths.
• Saving uploaded files or creating temporary files: Refer to related resources in the "See also" section below.

Cautions

• Lost changes: Changes to the disk file system path obtained from getRealPath() will be lost upon WAR redeployment, as they are not stored in the WAR file.
• Unreliability: getRealPath() may return null or unexpected paths if the server is not configured to expand the WAR file to the disk file system.

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