getRequestDispatcher如何在同一服务器的不同项目中的servlet中起作用? [英] How getRequestDispatcher will work for servlet in different project in same server?

问题描述

在servlet中，我们可以使用requestdispatcher，它将从一个servlet转发到同一项目中具有相同会话的另一个servlet.但是如果我使用的是不同的项目，则getRequestDispatcher不能正常工作.它给出了404错误.网址.如何在同一服务器的不同项目中实现getRequestDispatcher?

In servlet we can use requestdispatcher and it will forward from one servlet to another servlet with same session in same project.but if i am using different project getRequestDispatcher is not working.its giving 404 error.because its appending servlet name before the url. how can i achieve getRequestDispatcher in different project in same server?

RequestDispatcher rd = request.getRequestDispatcher("/v1/status1/toreply1"); 
rd.forward(request, response);

在同一项目中，getRequestDispatcher正常工作.但是在不同的项目中它不起作用?有人可以解释为什么它发生..吗?

In same project getRequestDispatcher working fine. but in different project its not working ?can anyone explain why its happening ..?

推荐答案

您可以在同一服务器上的不同项目中实现getRequestDispatcher.

You can achieve getRequestDispatcher in different project on same server.

签出 https://stackoverflow.com/a/19273223/1428052

它通过使用在同一服务器上针对不同项目 getServletContext().getContext()方法.

It works on same server for different project by using getServletContext().getContext() method.

您可以按照以下步骤进行详细实施.

You can follow below steps for detail implementation.

首先，您需要在下面的文件中进行更改

First you need to make changes in below file

(Windows)C:\ Program Files \ Apache Software Foundation \ Tomcat 7.0 \ conf \ context.xml 将crossContext的值设置为true.

(Windows) C:\Program Files\Apache Software Foundation\Tomcat 7.0\conf\context.xml Set value of crossContext to true.

context.xml

<Context crossContext="true">

    <!-- Default set of monitored resources -->
    <WatchedResource>WEB-INF/web.xml</WatchedResource>

    <!-- Uncomment this to disable session persistence across Tomcat restarts -->
    <!--
    <Manager pathname="" />
    -->

    <!-- Uncomment this to enable Comet connection tacking (provides events
         on session expiration as well as webapp lifecycle) -->
    <!--
    <Valve className="org.apache.catalina.valves.CometConnectionManagerValve" />
    -->

</Context>

请注意， crossContext ="true" .

假设您有两个名称为 InterServletComm1 和 InterServletComm2 的Web应用程序 每个Web应用程序中分别具有servlets Servlet1 和 Servlet1 .然后，每个servlet中的代码如下:

Suppose you have two web applications with name InterServletComm1 and InterServletComm2 having servlets Servlet1 and Servlet1 in each web application respectively. Then the code in each servlets goes as follows:

Servlet1.java

package interServletComm1;

import java.io.IOException;
import java.io.PrintWriter;

import javax.servlet.RequestDispatcher;
import javax.servlet.ServletContext;
import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

/**
 * Servlet implementation class Servlet1
 */
@WebServlet("/Servlet1")
public class Servlet1 extends HttpServlet {
    private static final long serialVersionUID = 1L;

    /**
     * @see HttpServlet#HttpServlet()
     */
    public Servlet1() {
        super();
        // TODO Auto-generated constructor stub
    }

    /**
     * @see HttpServlet#doGet(HttpServletRequest request, HttpServletResponse response)
     */
    protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException 
    {
        response.setContentType("text/html");
        PrintWriter pw = response.getWriter();

        request.setAttribute("name", "WebApp1");
        ServletContext context = getServletContext().getContext("/InterServletComm2");
        RequestDispatcher rd = context.getRequestDispatcher("/Servlet2");
        rd.forward(request, response);
    }

    /**
     * @see HttpServlet#doPost(HttpServletRequest request, HttpServletResponse response)
     */
    protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        // TODO Auto-generated method stub
    }

}

Servlet2.java

package interServletComm2;

import java.io.IOException;
import java.io.PrintWriter;

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

/**
 * Servlet implementation class Servlet2
 */
@WebServlet("/Servlet2")
public class Servlet2 extends HttpServlet {
    private static final long serialVersionUID = 1L;

    /**
     * @see HttpServlet#HttpServlet()
     */
    public Servlet2() {
        super();
        // TODO Auto-generated constructor stub
    }

    /**
     * @see HttpServlet#doGet(HttpServletRequest request, HttpServletResponse response)
     */
    protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException 
    {
        response.setContentType("text/html");
        PrintWriter pw = response.getWriter();
        String name = (String) request.getAttribute("name");
        pw.println("This is web application 2.");
        pw.println("<br>The value received from web application one is: " + name);
    }

    /**
     * @see HttpServlet#doPost(HttpServletRequest request, HttpServletResponse response)
     */
    protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        // TODO Auto-generated method stub
    }

}

以上代码从 InterServletComm1 发送属性 name ，并在 InterServletComm2 中接收该属性. 如果这个答案不清楚，请告诉我.

Above code sends attribute name from InterServletComm1 and it is received in InterServletComm2. Please let me know if this answer is not clear.

这篇关于getRequestDispatcher如何在同一服务器的不同项目中的servlet中起作用?的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！