embedded jetty forward from servlet to jsp

问题

Im try to get my embedded jetty servlet to do some processing and then pass control over to a JSP which will generate a result page.

The servlet gets mapped and called correctly however it fails to find the JSP. Since Im using embedded jetty I don't have a web.xml nor do I have a war. Maybe this means jetty doesn't know where to look for my JSP or something. If this is the case how can I tell eclipse/jetty where to find this or is there something Im missing with how I am calling the forward.

N.B. Im using a regular maven project so had to create the WEB-INF folder myself. Might be a clue to what's wrong!?

import java.io.IOException;

import javax.servlet.RequestDispatcher;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import org.eclipse.jetty.server.Server;
import org.eclipse.jetty.servlet.ServletContextHandler;
import org.eclipse.jetty.servlet.ServletHolder;
import org.springframework.core.io.ClassPathResource;

public class RunHelloServlet {

public static void main(String[] args) throws Exception {
    Server server = new Server(8080);

    ServletContextHandler contextHandler = new ServletContextHandler(ServletContextHandler.SESSIONS);

    contextHandler.setContextPath(".");
    server.setHandler(contextHandler);

    contextHandler.addServlet(new ServletHolder(new HelloServlet()), "/hello");

    server.start();
    server.join();
}

public static class HelloServlet extends HttpServlet {
    private static final long serialVersionUID = 1L;

    public HelloServlet() {
    }

    protected void doGet(HttpServletRequest request, HttpServletResponse response) throws IOException {
        String par1 = request.getParameter("par1");
        request.setAttribute("key", par1);

        // logic

        try {
            RequestDispatcher r = request.getRequestDispatcher("/result.jsp");
            request.getRequestDispatcher("/WEB-INF/result.jsp").forward(request, response);
        }
        catch (ServletException e1) {
            e1.printStackTrace();
        }

    }
}

}

My pom is as follows...

<project xmlns="http://maven.apache.org/POM/4.0.0"     xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
  xsi:schemaLocation="http://maven.apache.org/POM/4.0.0     http://maven.apache.org/xsd/maven-4.0.0.xsd">
  <modelVersion>4.0.0</modelVersion>

  <groupId>com.hp.it.kmcs.search</groupId>
  <artifactId>JettyTest</artifactId>
  <version>0.0.1-SNAPSHOT</version>
  <packaging>jar</packaging>

  <name>JettyTest</name>
  <url>http://maven.apache.org</url>

 <properties>
    <jettyVersion>7.2.0.v20101020</jettyVersion>
  </properties>

  <dependencies>
    <dependency>
        <groupId>org.eclipse.jetty.aggregate</groupId>
        <artifactId>jetty-all-server</artifactId>
        <version>7.6.0.RC1</version>
        <type>jar</type>
        <scope>compile</scope>
    </dependency>
    <dependency>
        <groupId>org.springframework</groupId>
        <artifactId>spring-core</artifactId>
        <version>3.1.0.RELEASE</version>
        <type>jar</type>
        <scope>compile</scope>
    </dependency>
  </dependencies>

  <build>
<plugins>
  <plugin>
    <!-- This plugin is needed for the servlet example -->
    <groupId>org.mortbay.jetty</groupId>
    <artifactId>jetty-maven-plugin</artifactId>
    <version>${jettyVersion}</version>
  </plugin>
  <plugin>
    <groupId>org.codehaus.mojo</groupId>
    <artifactId>exec-maven-plugin</artifactId>
    <version>1.1</version>
    <executions>
      <execution><goals><goal>java</goal></goals></execution>
    </executions>
    <configuration>
      <mainClass>com.hp.it.kmcs.JettyTest.RunHelloServlet</mainClass>
    </configuration>
  </plugin>
</plugins>

回答1:

So I got this to work using setWar and the correct jars. Using this code it is possible to both address the jsp directly (localhost:8080/result.jsp)and more importantly forward to the jsp using servlets (localhost:8080/hello) .forward command. This will enable me to serve up some dynamic content with my jsp.

Code as follows... (NB: Embedded Jetty => no web.xml is required)

import java.io.File;
import java.io.IOException;

import javax.servlet.RequestDispatcher;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import org.eclipse.jetty.server.Handler;
import org.eclipse.jetty.server.Server;
import org.eclipse.jetty.server.handler.DefaultHandler;
import org.eclipse.jetty.server.handler.HandlerList;
import org.eclipse.jetty.servlet.ServletHolder;
import org.eclipse.jetty.webapp.WebAppContext;

public class RunHelloServlet {

public static void main(String[] args) throws Exception {

    System.setProperty("DEBUG", "true");
    Server server = new Server(8080);

    WebAppContext webappcontext = new WebAppContext();
    webappcontext.setContextPath("/");

    File warPath = new File("C:/dev/workspace/JettyTest", "src/main/webapp");
    webappcontext.setWar(warPath.getAbsolutePath());
    HandlerList handlers = new HandlerList();
    webappcontext.addServlet(new ServletHolder(new HelloServlet()), "/hello");

    handlers.setHandlers(new Handler[] { webappcontext, new DefaultHandler() });
    server.setHandler(handlers);
    server.start();
}

public static class HelloServlet extends HttpServlet {
    private static final long serialVersionUID = 1L;

    public HelloServlet() {
    }

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

        // logic

        try {
            request.getRequestDispatcher("/result.jsp").forward(request, response);
        }
        catch (Throwable e1) {
            e1.printStackTrace();
        }

    }
}
}

POM.xml...

<project xmlns="http://maven.apache.org/POM/4.0.0"     xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
  xsi:schemaLocation="http://maven.apache.org/POM/4.0.0     http://maven.apache.org/xsd/maven-4.0.0.xsd">
  <modelVersion>4.0.0</modelVersion>

  <groupId>com.hp.it.kmcs.search</groupId>
  <artifactId>JettyTest</artifactId>
  <version>0.0.1-SNAPSHOT</version>
  <packaging>jar</packaging>

  <name>JettyTest</name>
  <url>http://maven.apache.org</url>

<properties>
    <jettyVersion>7.2.0.v20101020</jettyVersion>
</properties>
<dependencies>

    <dependency>
    <groupId>org.eclipse.jetty</groupId>
    <artifactId>jetty-server</artifactId>
    <version>7.6.0.RC1</version>
    <type>jar</type>
    <scope>compile</scope>
</dependency>
<dependency>
    <groupId>org.eclipse.jetty</groupId>
    <artifactId>jetty-util</artifactId>
    <version>7.6.0.RC1</version>
    <type>jar</type>
    <classifier>config</classifier>
    <scope>compile</scope>
</dependency>

<dependency>
    <groupId>org.mortbay.jetty</groupId>
    <artifactId>jsp-2.1-glassfish</artifactId>
    <version>2.1.v20100127</version>
    <type>jar</type>
    <scope>compile</scope>
</dependency>
<dependency>
    <groupId>org.eclipse.jdt.core.compiler</groupId>
    <artifactId>ecj</artifactId>
    <version>3.5.1</version>
    <type>jar</type>
    <scope>compile</scope>
</dependency>

<dependency>
    <groupId>org.mortbay.jetty</groupId>
    <artifactId>servlet-api-2.5</artifactId>
    <version>6.1.14</version>
    <type>jar</type>
    <scope>compile</scope>
</dependency>

<dependency>
    <groupId>org.eclipse.jetty</groupId>
    <artifactId>jetty-webapp</artifactId>
    <version>7.6.0.RC0</version>
    <type>jar</type>
    <scope>compile</scope>
    </dependency>
</dependencies>

  <build>
    <plugins>
      <plugin>
        <!-- This plugin is needed for the servlet example -->
        <groupId>org.mortbay.jetty</groupId>
       <artifactId>jetty-maven-plugin</artifactId>
        <version>${jettyVersion}</version>
      </plugin>
      <plugin>
        <groupId>org.codehaus.mojo</groupId>
        <artifactId>exec-maven-plugin</artifactId>
        <version>1.1</version>
        <executions>
          <execution><goals><goal>java</goal></goals></execution>
        </executions>
        <configuration>
          <mainClass>com.hp.it.kmcs.JettyTest.RunHelloServlet</mainClass>
        </configuration>
      </plugin>
    </plugins>
  </build>
</project>

回答2:

Does your embedding app console show INFO like this:

INFO:oejw.StandardDescriptorProcessor:NO JSP Support for /servletpath, did not find org.apache.jasper.servlet.JspServlet

Embedded Jetty by default does not have JSP support enabled. See here for details. HTH.

来源：https://stackoverflow.com/questions/8593496/embedded-jetty-forward-from-servlet-to-jsp

标签

jsp

servlets

jetty

forwarding

embedded-jetty