Tomcat启动后仍报404错误，Eclipse NEON重启后故障求助

Hey there, let's work through this 404 issue step by step—since everything ran smoothly before Eclipse crashed and you restarted it, this is almost certainly a configuration glitch rather than a core code problem. Here are the most practical fixes I'd try first:

• Double-check project deployment status in Eclipse
  Open the Servers view in Eclipse, right-click your Tomcat 8.5 instance, and select Add and Remove.... Make sure your project is listed under Configured—sometimes Eclipse drops deployed projects unexpectedly after a forced restart. If it's only in Available, move it over and restart Tomcat.

• Verify port 8080 isn't being used by another process
  Forced restarts can leave old Tomcat instances running in the background, hogging port 8080.

  • On Windows: Open Command Prompt and run netstat -ano | findstr :8080 to find the process ID (PID) using the port, then open Task Manager to end that process.
  • On Mac/Linux: Run lsof -i :8080 in terminal, then kill the process with kill <PID>.
    Once the port is free, restart Tomcat.

• Confirm context root and deployment path
  Right-click your Tomcat instance → Properties → Web Module Settings.

  • Check that the Context Root matches the URL you're using to access your app (e.g., if your context root is /my-project, you need to visit http://localhost:8080/my-project, not just the root localhost:8080).
  • Ensure the Document Base points to your project's WebContent folder (or src/main/webapp if it's a Maven project)—SVN re-downloads sometimes mess up path mappings.

• Dig into Tomcat logs for clues
  Head to your Tomcat installation's logs folder and check these files:

  • localhost.log: Logs app-specific startup errors
  • catalina.out (Mac/Linux) or catalina.log (Windows): Shows Tomcat-wide deployment issues
    If you see errors like "Context initialization failed" or missing dependencies, that's a clear sign your app isn't deploying properly, which causes the 404.

• Clear caches and rebuild

  • In Eclipse, go to Project → Clean..., select your project, and let it rebuild.
  • Right-click Tomcat → Clean... to wipe Tomcat's temporary deployment files.
  • Manually delete the work folder in your Tomcat installation directory—this clears cached class files that might be corrupted.

• Ensure your SVN project is fully intact
  Even after re-downloading, sometimes files go missing:

  • Check WEB-INF/lib for all required JAR files.
  • If it's a Maven project, run mvn clean install in terminal to recompile and pull dependencies.

内容的提问来源于stack exchange，提问作者Kondziowsky