Forum:

Servlets

i would like to know how to redirect a console output to textarea

Greenhorn

Posts: 8

posted 9 years ago

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i am doing a program that allow user to run and execute java language in this commandline.jsp, a servlet execute.java , jsp called getconsoleoutput.jsp to direct it to commandline.jsp

however there a compilation errors cos i could only get a line of string, and when i run loop in commandline.jsp it will not have the output. i could only run helloworld in it.
therefore i need code that i can run multiple line in it. i suspect its the print stream error in execute.java

<!DOCTYPE html>
<html>

<head>
	<title>java interpreter</title>
	<script src="http://ajax.googleapis.com/ajax/libs/jquery/1.3.2/jquery.min.js"></script>
	<script src="jquery-linedtextarea.js"></script>
	<link href="jquery-linedtextarea.css" type="text/css" rel="stylesheet" />
	
	<script type="text/javascript">
  
	var xmlHttp;
	function submitCode(str) {
		 
			if (typeof XMLHttpRequest != "undefined") {
				xmlHttp = new XMLHttpRequest();
			} else if (window.ActiveXObject) {
				xmlHttp = new ActiveXObject("Microsoft.XMLHTTP");
			}
			if (xmlHttp == null) {
				alert("Browser does not support XMLHTTP Request");
				return;
			}
			var url = "Execute";
			url += "?Cmdtextarea=" + str;
			xmlHttp.onreadystatechange = stateChange;
			xmlHttp.open("POST", url, true);
			xmlHttp.send(null);

}

function stateChange() {
		if (xmlHttp.readyState == 4 || xmlHttp.readyState == "complete") {
			var outputString = xmlHttp.responseText;
			document.getElementById("Optextarea").value = outputString;
	}
	}
	
    </script>
    
    
    <meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1">
	
	
</head>
<body>

<h1>java interpreter</h1>

<p>Please write/run your coding here</p>

</textarea>

$( document ).ready(function() {
  // Handler for .ready() called.
  
	$(".lined").linedtextarea(
		{selectedLine: 1}
	);
});

</script><br>

<p></p>

</body>
</html>

package Servlet;

import groovy.lang.GroovyShell;

import java.io.BufferedReader;
import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.PipedInputStream;
import java.io.PipedOutputStream;
import java.io.PrintStream;

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

/**
 * Servlet implementation class Execute
 */
@WebServlet("/Execute")
public class Execute extends HttpServlet {
	private static final long serialVersionUID = 1L;
       
    /**
     * @see HttpServlet#HttpServlet()
     */
    public Execute() {
        super();
        // TODO Auto-generated constructor stub
    }

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

/**
	 * @see HttpServlet#doPost(HttpServletRequest request, HttpServletResponse response)
	 */
	protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
		// TODO Auto-generated method stub
		
		GroovyShell shell = new GroovyShell();
		String Txtarea = request.getParameter("Cmdtextarea");

// Create a stream to hold the output
	    ByteArrayOutputStream baos = new ByteArrayOutputStream();
	    PrintStream ps = new PrintStream(baos);
	    // IMPORTANT: Save the old System.out!
	    PrintStream old = System.out;
	    // Tell Java to use your special stream
	    System.setOut(ps);
	    // Print some output: goes to your special stream
		
	    Object value = shell.evaluate(Txtarea);

// Put things back
	    System.out.flush();
	    System.setOut(old);
	    // Show what happened
	 
	    String outputString = baos.toString();
	    HttpSession session = request.getSession(true);
	    response.getWriter().println(outputString);

}}

[added code tags]

Jeanne Boyarsky

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Posts: 41878

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posted 9 years ago

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chan choon chee wrote:however there a compilation errors cos i could only get a line of string, and when i run loop in commandline.jsp it will not have the output. i could only run helloworld in it.

What is the error message the compiler is giving you?

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