CODEWITHSUNDEEP
javajspservlets
HiPownedBi
HiPownedBi

Reputation: 195

how to use or call java class in servlet and display the result to jsp

I am able to pass the searchterm in NewFile.jsp to HelloWorld servlet and display the result in wecome jsp. I have another program wrote in the new java class.I do not know how to pass the searchterm to the java class. so as to run the program.

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">
  <servlet>
    <servlet-name>Hello</servlet-name>
    <servlet-class>HelloWorld</servlet-class>
  </servlet>
  <servlet-mapping>
    <servlet-name>Hello</servlet-name>
    <url-pattern>/HelloWorld</url-pattern>
  </servlet-mapping>
</web-app>

NewFile.jsp

<%@ page language="java" contentType="text/html; charset=ISO-8859-1"  
    pageEncoding="ISO-8859-1"%>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" 
    "http://www.w3.org/TR/html4/loose.dtd">
<html>
    <head>
        <meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1">
        <title> My JSP page </title>
    </head> 
    <body>      
        <form method="post" action="HelloWorld">            
             Please enter a Keyword <br>
            <input type="text" name="searchTerm"size="20px">
            <input type="submit" value="submit">                        
        </form>     
    </body> 
</html>

welcomepage.jsp

<%@ page language="java" contentType="text/html; charset=ISO-8859-1"
    pageEncoding="ISO-8859-1"%>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1">
<title>Insert title here</title>
</head>
<body>
<%String X = (String)request.getAttribute("searchTerm");%>

 The search word is<%=X %>

<%-- welcom <%=request.getAttribute("searchTerm")%> --%>

</body>
</html>

servlet: HelloWorld.java

import java.io.IOException;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.PrintWriter;

public class HelloWorld extends HttpServlet { 
  protected void doGet(HttpServletRequest request, 
      HttpServletResponse response) throws ServletException, IOException 
  {
    doPost(request,response);

  }

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


    // ..........reading the user input
    String searchTerm= request.getParameter("searchTerm");  
  request.setAttribute("searchTerm",searchTerm);
  request.getRequestDispatcher("welcomepage.jsp").forward(request, response);


  }  

  }

the other javascript: Myprogram.java

public class ParameterPy {

public static void main(String a[]){
try{

String searchTerm="google";

ProcessBuilder pb = new ProcessBuilder("C:/Python27/python","D://program.py",""+searchTerm);
Process p = pb.start();

BufferedReader bfr = new BufferedReader(new InputStreamReader(p.getInputStream()));

System.out.println(".........start   process.........");  
String line = "";     
while ((line = bfr.readLine()) != null){
    System.out.println("Python Output: " + line);
}
System.out.println("........end   process.......");


}catch(Exception e){System.out.println(e);}
}
}

How do I link the variable searchterm in Myprogram.java with the variable in HelloWorld.java (replace the "google" to the real time user input search term) since the HelloWorld.java is a servlet can display to the jsp.

Upvotes: 0

Views: 11440

Answers (1)

Rohit Gaikwad
Rohit Gaikwad

Reputation: 3914

Use the below code:
ParameterPy class 

import java.io.BufferedReader;
import java.io.InputStreamReader;
public class ParameterPy
{

    public static void myMethodName(String searchTerm)  
        {
            try
                {
                    ProcessBuilder pb = new ProcessBuilder("C:/Python27/python", "D://program.py", ""+ searchTerm);
                    Process p = pb.start();

                    BufferedReader bfr = new BufferedReader(new InputStreamReader(p.getInputStream()));

                    System.out.println(".........start   process.........");
                    String line = "";
                    while ((line = bfr.readLine()) != null)
                        {
                            System.out.println("Python Output: " + line);
                        }
                    System.out.println("........end   process.......");

                } catch (Exception e)
                {
                    System.out.println(e);
                }
        }
}

HelloWorld Servlet:

import java.io.IOException;

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

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

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

      }

      protected void doPost(HttpServletRequest request, 
              HttpServletResponse response) throws ServletException, IOException 
          {
        // ..........reading the user input

      String searchTerm= request.getParameter("searchTerm");  

      ParameterPy.myMethodName(searchTerm);//Call to java class method

      request.setAttribute("searchTerm",searchTerm);
      request.getRequestDispatcher("welcomepage.jsp").forward(request, response);

      }  
}

For your query in comments, right now you are printing the result of ParameterPy on System.out. In order to display the result on jsp webpage you need JspWriter object, i.e, out.
For this I have amended your logic as below to return result as String. This String result will be displayed on jsp page.

import java.io.BufferedReader;
import java.io.InputStreamReader;
public class ParameterPy
{
    public static String myMethodName2(String searchTerm)   
        {
            StringBuilder sb=null;
            try
                {
                    ProcessBuilder pb = new ProcessBuilder("C:/Python27/python", "D://program.py", ""+ searchTerm);
                    Process p = pb.start();

                    BufferedReader bfr = new BufferedReader(new InputStreamReader(p.getInputStream()));

                    sb=new StringBuilder();
                    sb.append(".........start   process.........");
                    String line = "";
                    while ((line = bfr.readLine()) != null)
                        {
                            sb.append("Python Output: " + line);
                        }
                    sb.append("........end   process.......");

                } catch (Exception e)
                {
                    System.out.println(e);
                }
                return sb.toString();
        }
}

JSP:

<%@ page language="java" contentType="text/html; charset=ISO-8859-1"
pageEncoding="ISO-8859-1" import="stack.filter.ParameterPy"%>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1">
<title>Insert title here</title>
</head>
<body>
<%
    String searchTerm = request.getParameter("searchTerm");
    out.println(ParameterPy.myMethodName2(searchTerm));
%>
</body>
</html>

Upvotes: 1

Related Questions