将Java Web应用部署至Tomcat 7时遇到问题求助

Hey there! Let's walk through troubleshooting your Tomcat 7 deployment issue step by step—since you mentioned you've dropped the .war into the webapps directory but things aren't working as expected, here are the most common fixes and checks to get your RESTful Java Web API up and running:

This is the single most important step for debugging deployment issues. Head to the logs/ folder in your Tomcat installation directory and check these files:

• catalina.log: Catches server-wide errors, like classpath issues or missing dependencies.
• localhost.log: Logs application-specific startup errors, such as failed database connections or misconfigured servlets.
• If your app has its own logging setup, look for a separate log file (often named after your app) in the same directory.

9 times out of 10, the error message here will point you directly to the problem—whether it's a missing JDBC driver, incompatible library version, or invalid annotation.

Glassfish includes some libraries out of the box that Tomcat doesn't, so your NetBeans-built WAR might be missing critical dependencies:

• Open your .war file (you can use any zip tool) and check the WEB-INF/lib/ folder: It should contain all third-party jars your app needs (JAX-RS provider like Jersey, database drivers, JSON processing libraries, etc.). If you relied on Glassfish's built-in libraries during testing, you'll need to add these jars to your project in NetBeans and re-build the WAR.
• Double-check your WEB-INF/web.xml (or annotation-based config if you're using Servlet 3.0+) to ensure REST endpoints are mapped correctly. For JAX-RS apps, make sure your Application subclass is annotated with @ApplicationPath("/") (or your desired base path) and that it's being picked up by Tomcat.

Tomcat 7 supports Servlet 3.0 and Java 6/7—if your app uses newer features, you'll hit roadblocks:

• Confirm your project's target Java version in NetBeans: Go to Project Properties > Sources > Source/Binary Format and set it to Java 6 or 7 (Tomcat 7 doesn't fully support Java 8 features by default).
• Unlike Glassfish, Tomcat 7 doesn't include a JAX-RS implementation. If your app uses REST APIs, you must include a JAX-RS provider (like Jersey 2.x) and all its dependencies in WEB-INF/lib/.

Tomcat's auto-unpack feature can sometimes fail due to cached files or permission issues:

1. Stop Tomcat completely.
2. Delete any existing unpacked directory of your app in the webapps/ folder (this avoids conflicts with old, leftover files).
3. Copy your fresh .war file into webapps/.
4. Start Tomcat again and watch the logs for deployment messages.

• Also, ensure the user running Tomcat has read/write permissions on the webapps/ directory and your .war file—without these, Tomcat can't unpack or run the app.

Don't forget Tomcat uses the WAR filename as the context path. If your WAR is named my-java-app.war, your app will be accessible at http://localhost:8080/my-java-app/—so your REST endpoints will be prefixed with this path. For example, an endpoint mapped to /users would be accessed at http://localhost:8080/my-java-app/users, not just http://localhost:8080/users like you might have tested in Glassfish.

内容的提问来源于stack exchange，提问作者Vindaloo