Spring MVC小型购物车项目打包运行报404错误求助

Hey there, let’s work through this 404 issue together—since your individual pages run fine but the full packaged project throws an error, it’s almost certainly a configuration or routing misstep. Let’s break down the key checks to fix this:

First, dive into your web.xml and NikiAbb-servlet.xml:

• In web.xml, confirm your DispatcherServlet is mapped correctly. For Spring MVC, the standard url-pattern is / (not /*, which can cause issues with static resources). Example:

  <servlet-mapping>
      <servlet-name>NikiAbb</servlet-name>
      <url-pattern>/</url-pattern>
  </servlet-mapping>
  

• In NikiAbb-servlet.xml, make sure your component scan covers the package where AddController.java lives. If your controller is in com.nikiabb.controller, the scan should look like this:

  <context:component-scan base-package="com.nikiabb.controller"/>
  

  If this path is wrong, Spring won’t detect your controller at all, leading to 404s.

Open up AddController.java and verify:

• The @RequestMapping annotations match the URL you’re trying to access. For example, if your controller has:

  @Controller
  @RequestMapping("/cart")
  public class AddController {
      @RequestMapping("/addProduct")
      public String showAddProductPage() {
          return "ViewAddproduct";
      }
  }
  

  Your full access URL should be http://localhost:8080/[your-project-name]/cart/addProduct, not just /addProduct or directly accessing the JSP.
• Ensure the returned view name (like "ViewAddproduct") exactly matches your JSP filename (including capitalization). Windows ignores case, but Tomcat (especially when deployed as a WAR) is case-sensitive—ViewAddproduct.jsp vs viewaddproduct.jsp are treated as different files.

Your pom.xml and resulting WAR file need to be correctly structured:

• Check that <packaging>war</packaging> is set in pom.xml—this ensures Maven builds a valid web archive.
• Unzip your generated WAR file and verify:
  • JSPs are in the right location. If you’re using InternalResourceViewResolver in NikiAbb-servlet.xml with a prefix like /WEB-INF/views/, your ViewAddproduct.jsp must be inside WEB-INF/views/ (not directly in WEB-INF or the root). Example resolver config:

    <bean class="org.springframework.web.servlet.view.InternalResourceViewResolver">
        <property name="prefix" value="/WEB-INF/views/"/>
        <property name="suffix" value=".jsp"/>
    </bean>
    

  • All Spring dependencies are present in WEB-INF/lib/. Sometimes Maven skips dependencies during packaging—compare the JARs here to what’s in your local Maven repository to ensure nothing’s missing.

When deploying a WAR to Tomcat, the context path defaults to your WAR filename (unless you configure it otherwise). For example, if your WAR is named NikiAbb.war, your base URL becomes http://localhost:8080/NikiAbb/.

• In Eclipse, you might have tested pages directly (like http://localhost:8080/ViewAddproduct.jsp), but in the packaged project, you can’t access JSPs directly if they’re in WEB-INF—you have to go through your controller mappings instead.

JDK 9’s module system can cause issues with older Spring versions:

• If you’re using Spring 4.x, it has limited support for JDK 9. Your best bet is to either downgrade to JDK 8 (the most stable for Spring projects) or upgrade to Spring 5.x+, which fully supports JDK 9+.
• If you stick with JDK 9, make sure your pom.xml sets the correct compiler source/target:

  <properties>
      <maven.compiler.source>9</maven.compiler.source>
      <maven.compiler.target>9</maven.compiler.target>
  </properties>
  

404 is often a symptom of an underlying issue. Check Tomcat’s logs (look in [tomcat-dir]/logs/ for localhost.log or catalina.out):

• Look for ClassNotFoundException (indicates missing dependencies) or errors during controller initialization (means Spring couldn’t load your controller). These logs will give you a clearer picture of what’s broken beyond just the 404.

内容的提问来源于stack exchange，提问作者NikNik