Eclipse Java EE 和 Tomcat 7：错误 404，请求的资源不可用
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Eclipse Java EE and Tomcat 7: Error 404, requested resource not available
提问by user2979063
Tomcat 7 on Eclipse Java EE is displaying HTTP STATUS 404, and THE REQUESTED RESOURCE IS NOT AVAILABLE. 1) i dont know what i am not doing right? I have read loads of post on the sight and attempted to do what was possible to do, yet nothing has change. In some cases i got back my source code as a downloadable text file.
Eclipse Java EE 上的 Tomcat 7 显示 HTTP 状态 404，并且请求的资源不可用。1）我不知道我做错了什么？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取回。
This is my servlet program below:
这是我的 servlet 程序如下：
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();
}
}
}
}
And following is my /META-INF/Context.xml code:
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>
And also below is my /Web_INF/web.xml :
下面是我的 /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>
The console output is:
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 Server0\Tools\Binn\;c:\Program Files\Microsoft SQL Server0\Tools\Binn\;c:\Program Files\Microsoft SQL Server0\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 Server0\Tools\Binn\;c:\Program Files\Microsoft SQL Server0\Tools\Binn\;c:\Program Files\Microsoft SQL Server0\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 Server0\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 Server0\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
Your help is highly appreciated.
非常感谢您的帮助。
回答by Pat
As you have not provided the URL that you are using, I am guessing that you may be missing the Context Root in your URL. Ideally, you should use a URL similar to this for accessing your servlet:
由于您没有提供您正在使用的 URL，我猜您可能在您的 URL 中缺少上下文根。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
where context_rootis usually the name of your application (WAR file). For example, if your WAR file is MyApplication.war, then you have to use below URL:
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
However, you have the option to override this using Context.xml file on Tomcat. For example, below <Context>tag in Context.xml would set the context_root to SomeApp
但是，您可以选择使用 Tomcat 上的 Context.xml 文件来覆盖它。例如，<Context>在 Context.xml 中的下方标记会将 context_root 设置为SomeApp
<Context crossContext="true" docBase="SomeApp" path="" reloadable="true" >
Then, to access the same application, you can use URL:
然后，要访问相同的应用程序，您可以使用 URL：
http://<server>:<port>/SomeApp/TennisdbaseServlet.do
回答by Deepak
When with the j2eeview is provided as JSPwhy are u doing it with servlets only .Try to do it with JSP.Also i think your access pattern of the servlet is not correct this should be some thing like this http://localhost:port/app-name/dbservlet.Also u have not defined any servlet with url-pattern/dbservlet. Below is a good tutorial you can start with.
http://www.mkyong.com/servlet/a-simple-servlet-example-write-deploy-run/
当提供j2ee视图时，JSP为什么你只用 servlet 来做它。尝试用 JSP 来做。另外我认为你的 servlet 访问模式不正确，这应该是这样的http://localhost:port/app-name/dbservlet。另外你还没有定义任何 servlet与url-pattern/dbservlet. 下面是一个很好的教程，你可以开始。
http://www.mkyong.com/servlet/a-simple-servlet-example-write-deploy-run/
回答by Anirudh
I don't really understand how could the below code even compile:
我真的不明白下面的代码是如何编译的：
Context envContext = null;
try {
Context envContext = new InitialContext();
First you should always get rid of the compile time errors and then try to call the servlet: below is the a compiler error free code:
首先，您应该始终摆脱编译时错误，然后尝试调用 servlet：以下是无编译器错误的代码：
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();
}
}
}
Try running it with this first and then debug the errors henceforth if any!!
尝试先运行它，然后调试此后的错误（如果有）！
