如何在servlet中使用或调用Java类并将结果显示给jsp

Question

I am able to pass the searchterm in NewFile.jsp to HelloWorld servlet and display the result in wecome jsp. 我可以将NewFile.jsp中的searchterm传递给HelloWorld servlet，并在欢迎使用的jsp中显示结果。 I have another program wrote in the new java class.I do not know how to pass the searchterm to the java class. 我在新的java类中编写了另一个程序，我不知道如何将searchterm传递给java类。 so as to run the program. 以便运行程序。

web.xml 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 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 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 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 其他的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. 由于HelloWorld.java是一个可以显示到jsp的servlet，因此如何将Myprogram.java中的变量searchterm与HelloWorld.java中的变量链接（将“ google”替换为实时用户输入搜索词）。

Answer 1

Use the below code: 使用以下代码：
ParameterPy class ParameterPy类

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: 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 . 对于注释中的查询，现在您将在System.out上打印ParameterPy的结果。 In order to display the result on jsp webpage you need JspWriter object, ie, out . 为了在jsp网页上显示结果，您需要JspWriter对象，即out 。
For this I have amended your logic as below to return result as String . 为此，我修改了以下逻辑，将结果作为String返回。 This String result will be displayed on jsp page. 此String结果将显示在jsp页面上。

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: 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>

如何在servlet中使用或调用Java类并将结果显示给jsp

问题描述

1 个解决方案

解决方案1
1 2016-10-11 05:37:03

如何在servlet中使用或调用Java类并将结果显示给jsp

问题描述

1 个解决方案

解决方案1 1 2016-10-11 05:37:03

解决方案1
1 2016-10-11 05:37:03