错误：即使添加了 CLASSPATH 变量，包 javax.servlet.http 也不存在

Question

我正在尝试实现基本的 HelloServlet.java 程序。但它似乎产生了这些错误HelloServlet.java:7: error: cannot find symbolpublic class HelloServlet extends HttpServlet {                                  ^  symbol: class HttpServletHelloServlet.java:11: error: cannot find symbol   public void init() throws ServletException {                             ^  symbol:   class ServletException  location: class HelloServletHelloServlet.java:16: error: cannot find symbol   public void doGet(HttpServletRequest request, HttpServletResponse response)                     ^  symbol:   class HttpServletRequest  location: class HelloServletHelloServlet.java:16: error: cannot find symbol   public void doGet(HttpServletRequest request, HttpServletResponse response)                                                 ^  symbol:   class HttpServletResponse  location: class HelloServletHelloServlet.java:17: error: cannot find symbol      throws ServletException, IOException {             ^  symbol:   class ServletException  location: class HelloServletHelloServlet.java:3: error: package javax.servlet does not existimport javax.servlet.*;^HelloServlet.java:4: error: package javax.servlet.http does not existimport javax.servlet.http.*;^7 errors我已经为 jar 文件添加了 CLASSPATHnithinchandranp@b-40:~$ echo ${CLASSPATH}/home/nithinchandranp/ApacheTomcat/apache-tomcat-8.5.34/lib/*nithinchandranp@b-40:~$ 现在我做错了什么？请帮忙..

Answer 1

末尾带有 * 的类路径不适用于 jar 数据集。您必须将每个 jar 放在类路径中。

Answer 2

这是我的错误。

这就是我通过命令行创建 CLASSPATH 的方式

 export CLASSPATH=/home/nithinchandranp/ApacheTomcat/apache-tomcat-8.5.34/lib/*

我创建的目录不是ApacheTomcat，而是Apache Tomcat（中间有一个空格）。

也许这就是 CLASSPATH 变量无法识别正确位置的原因。

我将目录名称更改为 ApacheTomcat（删除了空格）。

现在我在 .bashrc 文件中定义了 CLASSPATH 变量，如下所示：

#classpath

export CLASSPATH=/home/nithinchandranp/ApacheTomcat/apache-tomcat-8.5.34/lib/*

现在，当我执行 echo${CLASSPATH} 时，我得到了我提到的所有 jar 文件。

nithinchandranp@b-40:~$ echo ${CLASSPATH}

/home/nithinchandranp/ApacheTomcat/apache-tomcat-8.5.34/lib/annotations-api.jar /home/nithinchandranp/ApacheTomcat/apache-tomcat-8.5.34/lib/catalina-ant.jar /home/nithinchandranp/ApacheTomcat/apache-tomcat-8.5.34/lib/catalina-ha.jar /home/nithinchandranp/ApacheTomcat/apache-tomcat-8.5.34/lib/catalina.jar /home/nithinchandranp/ApacheTomcat/apache-tomcat-8.5.34/lib/catalina-storeconfig.jar /home/nithinchandranp/ApacheTomcat/apache-tomcat-8.5.34/lib/catalina-tribes.jar /home/nithinchandranp/ApacheTomcat/apache-tomcat-8.5.34/lib/ecj-4.6.3.jar /home/nithinchandranp/ApacheTomcat/apache-tomcat-8.5.34/lib/el-api.jar /home/nithinchandranp/ApacheTomcat/apache-tomcat-8.5.34/lib/jasper-el.jar /home/nithinchandranp/ApacheTomcat/apache-tomcat-8.5.34/lib/jasper.jar /home/nithinchandranp/ApacheTomcat/apache-tomcat-8.5.34/lib/jaspic-api.jar /home/nithinchandranp/ApacheTomcat/apache-tomcat-8.5.34/lib/jsp-api.jar /home/nithinchandranp/ApacheTomcat/apache-tomcat-8.5.34/lib/servlet-api.jar /home/nithinchandranp/ApacheTomcat/apache-tomcat-8.5.34/lib/tomcat-api.jar /home/nithinchandranp/ApacheTomcat/apache-tomcat-8.5.34/lib/tomcat-coyote.jar /home/nithinchandranp/ApacheTomcat/apache-tomcat-8.5.34/lib/tomcat-dbcp.jar /home/nithinchandranp/ApacheTomcat/apache-tomcat-8.5.34/lib/tomcat-i18n-es.jar /home/nithinchandranp/ApacheTomcat/apache-tomcat-8.5.34/lib/tomcat-i18n-fr.jar /home/nithinchandranp/ApacheTomcat/apache-tomcat-8.5.34/lib/tomcat-i18n-ja.jar /home/nithinchandranp/ApacheTomcat/apache-tomcat-8.5.34/lib/tomcat-i18n-ru.jar /home/nithinchandranp/ApacheTomcat/apache-tomcat-8.5.34/lib/tomcat-jdbc.jar /home/nithinchandranp/ApacheTomcat/apache-tomcat-8.5.34/lib/tomcat-jni.jar /home/nithinchandranp/ApacheTomcat/apache-tomcat-8.5.34/lib/tomcat-util.jar /home/nithinchandranp/ApacheTomcat/apache-tomcat-8.5.34/lib/tomcat-util-scan.jar /home/nithinchandranp/ApacheTomcat/apache-tomcat-8.5.34/lib/tomcat-websocket.jar /home/nithinchandranp/ApacheTomcat/apache-tomcat-8.5.34/lib/websocket-api.jar