Eclipse Java EE和Tomcat 7：错误404，请求的资源不可用

时间：2013-11-28 14:00:06

标签： java eclipse servlets tomcat7

Eclipse Java EE上的Tomcat 7正在显示HTTP状态404，并且请求的资源不可用。 1）我不知道我做得对吗？我已经阅读了大量关于视线的帖子并试图做可能做的事情，但没有任何改变。在某些情况下，我将源代码作为可下载的文本文件返回。

这是我的servlet程序：

package dbservlet;

 //all imports here

public class TennisdbaseServlet extends HttpServlet {
private static final long serialVersionUID = 1L;
public TennisdbaseServlet() {}

public void doGet(HttpServletRequest request,
   HttpServletResponse response)
   throws ServletException, IOException {

   Context envContext = null;
   try {

       Context envContext = new InitialContext(); 
       DataSource ds = (DataSource)envContext.lookup("java:/comp/env/jdbc/postgres"); 
       Connection con = ds.getConnection();

       Statement stmt = con.createStatement();
       String query = "select * from tennis_teams";
       ResultSet rs = stmt.executeQuery(query);

       PrintWriter out = response.getWriter();
       response.setContentType("text/html");
       out.print("<center><h1>Tennis Teams Info</h1></center>");
       out.print("<html><body><table border=\"1\" cellspacing=10 cellpadding=5>");
       out.print("<th>TEAM NUMBER</th>");
       out.print("<th>PLAYER NO</th>");
       out.print("<th>DIVISION</th>");

       while(rs.next())
       {
           out.print("<tr>");
           out.print("<td>" + rs.getInt("teamno") + "</td>");
           out.print("<td>" + rs.getString("playerno") + "</td>");
           out.print("<td>" + rs.getDouble("division") + "</td>");
           out.print("</tr>");
       }
       out.print("</table></body></html>");
   }  catch (SQLException e) {
       e.printStackTrace();
   } catch (NamingException e) {
       e.printStackTrace();
   }
  }

}

以下是我的/META-INF/Context.xml代码：

<?xml version="1.0" encoding="UTF-8"?>

<!-- The contents of this file will be loaded for web application -->

<Context crossContext="true" docBase="TennisdbaseServlet" path="" reloadable="true" >
  <!-- Default set of monitored resources -->
   <WatchedResource>WEB-INF/web.xml</WatchedResource>
   <Resource name="jdbc/postgres" auth="Container"
      type="javax.sql.DataSource" 
      driverClassName="org.postgresql.Driver"
      url="jdbc:postgresql://localhost:5432/tennisDB"
      username="ssssss" 
      password="ssssss" 
      maxActive="20" 
      maxIdle="10"
      maxWait="-1"/>
</Context>

以下是我的/Web_INF/web.xml：

<?xml version="1.0" encoding="UTF-8"?>
<web-app id="WebApp_ID" version="2.4"
xmlns="http://java.sun.com/xml/ns/j2ee"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://java.sun.com/xml/ns/j2ee http://java.sun.com/xml/ns   /j2ee/web-app_2_4.xsd">

<resource-ref>
<description>postgreSQL DataSource for Tennis Database Application</description>
<res-ref-name>jdbc/postgres</res-ref-name>
<res-type>javax.sql.DataSource</res-type>
<res-auth>Container</res-auth>
</resource-ref>

<display-name>TennisDatabasePool</display-name>

<servlet>
<servlet-name>TennisdbaseServlet</servlet-name>
<servlet-class>dbservlet.TennisdbaseServlet</servlet-class>
</servlet>
<servlet-mapping>
<servlet-name>TennisdbaseServlet</servlet-name>
<url-pattern>/TennisdbaseServlet.do</url-pattern>
</servlet-mapping>
</web-app>

控制台输出是：

Nov 28, 2013 1:42:29 PM org.apache.catalina.core.AprLifecycleListener init
INFO: The APR based Apache Tomcat Native library which allows optimal performance in   production environments was not found on the java.library.path: C:\Program Files\Java   \jre7\bin;C:\Windows\Sun\Java\bin;C:\Windows\system32;C:\Windows;C:\Program Files\Common  Files\Microsoft Shared\Microsoft Online Services;C:\Program Files (x86)\Common Files\Microsoft Shared\Microsoft Online Services;C:\Program Files\Common Files\Microsoft Shared\Windows Live;C:\Program Files (x86)\Common Files\Microsoft Shared\Windows Live;C:\Windows\system32;C:\Windows;C:\Windows\System32\Wbem;C:\Windows\System32\WindowsPowerShell\v1.0\;C:\Program Files (x86)\ATI Technologies\ATI.ACE\Core-Static\;C:\Program Files (x86)\Java\jre6\bin;C:\Program Files (x86)\Windows Live\Shared;c:\Program Files (x86)\Microsoft SQL Server\100\Tools\Binn\;c:\Program Files\Microsoft SQL Server\100\Tools\Binn\;c:\Program Files\Microsoft SQL Server\100\DTS\Binn\;PATH=C:\Program Files\Java\jdk1.7.0_45\bin;C:\Program Files\Common Files\Microsoft Shared\Microsoft Online Services;C:\Program Files (x86)\Common Files\Microsoft Shared\Microsoft Online Services;C:\Program Files\Common Files\Microsoft Shared\Windows Live;C:\Program Files (x86)\Common Files\Microsoft Shared\Windows Live;C:\Windows\system32;C:\Windows;C:\Windows\System32\Wbem;C:\Windows\System32\WindowsPowerShell\v1.0\;C:\Program Files (x86)\ATI Technologies\ATI.ACE\Core-Static\;C:\Program Files (x86)\Java\jre6\bin;C:\Program Files (x86)\Windows Live\Shared;c:\Program Files (x86)\Microsoft SQL Server\100\Tools\Binn\;c:\Program Files\Microsoft SQL Server\100\Tools\Binn\;c:\Program Files\Microsoft SQL Server\100\DTS\Binn\;PATH=C:\Program Files\Java\jdk1.7.0_45\bin;%PATH%;C:\Program Files\System Center Operations Manager 2007\;C:\Program Files (x86)\Microsoft ASP.NET\ASP.NET Web Pages\v1.0\;C:\Program Files\Microsoft SQL Server\110\Tools\Binn\;C:\Program Files\System Center Operations Manager 2007\;C:\Program Files (x86)\Microsoft ASP.NET\ASP.NET Web Pages\v1.0\;C:\Program Files\Microsoft SQL Server\110\Tools\Binn\;C:\Program Files (x86)\QuickTime\QTSystem\;C:\Program Files (x86)\Graphviz2.30\bin;C:\Program Files (x86)\MySQL\MySQL Utilities 1.3.4\;C:\Program Files\Java\jdk1.7.0_45\bin;C:\Program Files\Java\jre7\bin;.
Nov 28, 2013 1:42:33 PM org.apache.coyote.AbstractProtocol init
INFO: Initializing ProtocolHandler ["http-bio-8010"]
Nov 28, 2013 1:42:33 PM org.apache.coyote.AbstractProtocol init
INFO: Initializing ProtocolHandler ["ajp-bio-8009"]
Nov 28, 2013 1:42:33 PM org.apache.catalina.startup.Catalina load
INFO: Initialization processed in 5546 ms
Nov 28, 2013 1:42:33 PM org.apache.catalina.core.StandardService startInternal
INFO: Starting service Catalina
Nov 28, 2013 1:42:33 PM org.apache.catalina.core.StandardEngine startInternal
INFO: Starting Servlet Engine: Apache Tomcat/7.0.47
Nov 28, 2013 1:42:39 PM org.apache.catalina.startup.HostConfig deployDescriptor
INFO: Deploying configuration descriptor C:\Users\Windows\workspace\.metadata\.plugins\org.eclipse.wst.server.core\tmp1\conf\Catalina\localhost\TennisDatabasePool.xml
Nov 28, 2013 1:42:40 PM org.apache.catalina.startup.SetContextPropertiesRule begin
WARNING: [SetContextPropertiesRule]{Context} Setting property 'source' to 'org.eclipse.jst.jee.server:TennisDatabasePool' did not find a matching property.
Nov 28, 2013 1:42:43 PM org.apache.coyote.AbstractProtocol start
INFO: Starting ProtocolHandler ["http-bio-8010"]
Nov 28, 2013 1:42:43 PM org.apache.coyote.AbstractProtocol start
INFO: Starting ProtocolHandler ["ajp-bio-8009"]
Nov 28, 2013 1:42:43 PM org.apache.catalina.startup.Catalina start
INFO: Server startup in 10091 ms

非常感谢您的帮助。

3 个答案:

答案 0 :(得分：1)

由于您没有提供您正在使用的URL，我猜您可能错过了URL中的Context Root。理想情况下，您应该使用类似于此的URL来访问您的servlet：

http://<server>:<port>/<context_root>/TennisdbaseServlet.do

其中context_root通常是应用程序的名称（WAR文件）。例如，如果您的WAR文件是MyApplication.war，那么您必须使用以下URL：

http://<server>:<port>/MyApplication/TennisdbaseServlet.do

但是，您可以选择使用Tomcat上的Context.xml文件覆盖它。例如，Context.xml中的<Context>标记下面会将context_root设置为SomeApp 

<Context crossContext="true" docBase="SomeApp" path="" reloadable="true" >

然后，要访问同一个应用程序，您可以使用URL：

http://<server>:<port>/SomeApp/TennisdbaseServlet.do

答案 1 :(得分：0)

当j2ee视图以JSP的形式提供时，为什么你只使用servlet。尝试用JSP做。同时我认为你的servlet访问模式不正确有点像http://localhost:port/app-name/dbservlet这样的事情。你也没有用url-pattern /dbservlet定义任何servlet。下面是一个很好的教程，你可以从这开始 http://www.mkyong.com/servlet/a-simple-servlet-example-write-deploy-run/

答案 2 :(得分：0)

我真的不明白下面的代码怎么可以编译：

Context envContext = null;
   try {

       Context envContext = new InitialContext();

首先你应该总是摆脱编译时错误，然后尝试调用servlet：下面是编译器无错误代码：

import java.io.IOException;
import java.io.PrintWriter;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;

import javax.activation.DataSource;
import javax.naming.Context;
import javax.naming.InitialContext;
import javax.naming.NamingException;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import com.sun.corba.se.pept.transport.Connection;


public class TennisdbaseServlet extends HttpServlet {
private static final long serialVersionUID = 1L;
public TennisdbaseServlet() {}

public void doGet(HttpServletRequest request,
   HttpServletResponse response)
   throws ServletException, IOException {

   Context envContext = null;
   try {

       envContext =  new InitialContext(); 
       DataSource ds = (DataSource) envContext.lookup("java:/comp/env/jdbc/postgres"); 
       Connection con = (Connection) ((Statement) ds).getConnection();

       Statement stmt = ((java.sql.Connection) con).createStatement();
       String query = "select * from tennis_teams";
       ResultSet rs = stmt.executeQuery(query);

       PrintWriter out = response.getWriter();
       response.setContentType("text/html");
       out.print("<center><h1>Tennis Teams Info</h1></center>");
       out.print("<html><body><table border=\"1\" cellspacing=10 cellpadding=5>");
       out.print("<th>TEAM NUMBER</th>");
       out.print("<th>PLAYER NO</th>");
       out.print("<th>DIVISION</th>");

       while(rs.next())
       {
           out.print("<tr>");
           out.print("<td>" + rs.getInt("teamno") + "</td>");
           out.print("<td>" + rs.getString("playerno") + "</td>");
           out.print("<td>" + rs.getDouble("division") + "</td>");
           out.print("</tr>");
       }
       out.print("</table></body></html>");
   }  catch (SQLException e) {
       e.printStackTrace();
   } catch (NamingException e) {
       e.printStackTrace();
   }
  }
}

首先尝试运行它，然后再调试错误，如果有的话......

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