java - com.google.common.cache.Cache 类未找到错误

Question

我正在使用 Guava 14.0 jar，下面是我的代码

package org.user.module.test;

import java.io.IOException;
import java.io.PrintWriter;
import java.util.concurrent.TimeUnit;
import com.google.common.cache.CacheBuilder;
import com.google.common.cache.Cache;
import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

/**
 * Servlet implementation class test
 */
@WebServlet("/test")
public class test extends HttpServlet  {
    private static final long serialVersionUID = 1L;

    Cache<String, Integer> map;

    public test() {
        super();
        // TODO Auto-generated constructor stub
    }

    public void init() throws ServletException
    {
        map=CacheBuilder.newBuilder().
                maximumSize(100).
                expireAfterAccess(10, TimeUnit.MINUTES).
                build();

    }

    /**
     * @see HttpServlet#doGet(HttpServletRequest request, HttpServletResponse response)
     */
    protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        PrintWriter out=response.getWriter();
        String p=request.getParameter("v");
        Integer a=map.getIfPresent(p);
        if(a==null){
            map.put(p, 1);
            out.println("Putting The Integer:"+a);
        }
        else{
            map.put(p,a++);
            out.println("A is already present and the value is:"+a);
        }

    }

    /**
     * @see HttpServlet#doPost(HttpServletRequest request, HttpServletResponse response)
     */
    protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        doGet(request,response);
    }

}

错误:

SEVERE: Allocate exception for servlet org.user.module.test.test java.lang.ClassNotFoundException: com.google.common.cache.Cache at org.apache.catalina.loader.WebappClassLoader.loadClass(WebappClassLoader.java:1701) at org.apache.catalina.loader.WebappClassLoader.loadClass(WebappClassLoader.java:1546) at java.lang.Class.getDeclaredFields0(Native Method) at java.lang.Class.privateGetDeclaredFields(Class.java:2317) at java.lang.Class.getDeclaredFields(Class.java:1762) at org.apache.catalina.core.DefaultInstanceManager.populateAnnotationsCache(DefaultInstanceManager.java:276) at org.apache.catalina.core.DefaultInstanceManager.newInstance(DefaultInstanceManager.java:143) at org.apache.catalina.core.DefaultInstanceManager.newInstance(DefaultInstanceManager.java:125) at org.apache.catalina.core.StandardWrapper.loadServlet(StandardWrapper.java:1136) at org.apache.catalina.core.StandardWrapper.allocate(StandardWrapper.java:857) at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:135) at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:169) at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:472) at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:168) at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:98) at org.apache.catalina.valves.AccessLogValve.invoke(AccessLogValve.java:927) at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:118) at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:407) at org.apache.coyote.http11.AbstractHttp11Processor.process(AbstractHttp11Processor.java:987) at org.apache.coyote.AbstractProtocol$AbstractConnectionHandler.process(AbstractProtocol.java:579) at org.apache.tomcat.util.net.JIoEndpoint$SocketProcessor.run(JIoEndpoint.java:307) at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1145) at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:615) at java.lang.Thread.run(Thread.java:722)

从这里下载 jar Downlaod Link链接到我的项目文件夹(项目名称:test2)LINK

Answer 1

显而易见的答案是；从应用程序服务器指定的类路径中找不到 Google guava jar。 jar 应该存在于 WEB-INF/classes 或 WEB-INF/lib 中。 Apache Tomcat 还从 $CATALINA_HOME/lib 文件夹加载通用类。