[英]Deploying the java web application. some listenerStart error
我有下一個問題:我正在嘗試使用jre 6.0在我的Tomcat 7.0上部署應用程序...我創建了一個名為ListenerTester的servlet:
package com.example;
import javax.servlet.*;
import javax.servlet.http.*;
import java.io.*;
class ListenerTester extends HttpServlet {
public void doGet (HttpServletRequest request, HttpServletResponse response)
throws IOException, ServletException {
response.setContentType("text/html");
PrintWriter out = response.getWriter();
out.println("text context attributes set by listener<br />");
out.println("<br />");
Dog dog = (Dog) getServletContext().getAttribute("dog");
out.println("The dog`s breed is: " + dog.getBreed());
}
}
類dog是一個簡單的類,它只有一個字段String品種和getter以及帶有參數的Constructor。
下一個類是MyServletContextListener:
package com.example;
import javax.servlet.*;
class MyServletContextListener implements ServletContextListener {
public void contextInitialized(ServletContextEvent e) {
ServletContext sc = e.getServletContext();
String dogBreed = sc.getInitParameter("breed");
Dog f = new Dog(dogBreed);
sc.setAttribute("dog", f);
}
public void contextDestroyed(ServletContextEvent e) {
}
}
它們位於名為com.example的包中。 應用程序的頂級文件夾是listenerTester。
web.xml中:
<?xml version="1.0" encoding="UTF-8"?>
<web-app xmlns="http://java.sun.com/xml/ns/javaee"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://java.sun.com/xml/ns/javaee
http://java.sun.com/xml/ns/javaee/web-app_3_0.xsd"
version="3.0" >
<servlet>
<servlet-name>ListenerTester</servlet-name>
<servlet-class>com.example.ListenerTester</servlet-class>
</servlet>
<servlet-mapping>
<servlet-name>ListenerTester</servlet-name>
<url-pattern>/ListenTest.do</url-pattern>
</servlet-mapping>
<context-param>
<param-name>breed</param-name>
<param-value>Sparky</param-value>
</context-param>
<listener>
<listener-class>com.example.MyServletContextListener</listener-class>
</listener>
</web-app>
問題是下一個 - 當我嘗試運行它時 - 瀏覽器沒有顯示任何東西......根本沒有...沒有錯誤或任何東西。
When I look inside the catalina log file:
08.11.2011 0:23:56 org.apache.coyote.AbstractProtocolHandler init
INFO: Initializing ProtocolHandler ["http-bio-8080"]
08.11.2011 0:23:56 org.apache.coyote.AbstractProtocolHandler init
INFO: Initializing ProtocolHandler ["ajp-bio-8009"]
08.11.2011 0:23:56 org.apache.catalina.startup.Catalina load
INFO: Initialization processed in 331 ms
08.11.2011 0:23:56 org.apache.catalina.core.StandardService startInternal
INFO: Starting service Catalina
08.11.2011 0:23:56 org.apache.catalina.core.StandardEngine startInternal
INFO: Starting Servlet Engine: Apache Tomcat/7.0.8
08.11.2011 0:23:56 org.apache.catalina.startup.HostConfig deployDirectory
INFO: Deploying web application directory listenerTest
08.11.2011 0:23:56 org.apache.catalina.core.StandardContext startInternal
**SEVERE**: Error listenerStart
08.11.2011 0:23:56 org.apache.catalina.core.StandardContext startInternal
SEVERE: Context [/listenerTest] startup failed due to previous errors
08.11.2011 0:23:56 org.apache.coyote.AbstractProtocolHandler start
INFO: Starting ProtocolHandler ["http-bio-8080"]
08.11.2011 0:23:56 org.apache.coyote.AbstractProtocolHandler start
INFO: Starting ProtocolHandler ["ajp-bio-8009"]
08.11.2011 0:23:56 org.apache.catalina.startup.Catalina start
INFO: Server startup in 233 ms
你能告訴我該做什么,錯誤是什么嗎? 什么是listenerStart?
您應該將您的類公開而不是package-private。
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