[Solved] How to receive a file type parameter from html/jsp into a servlet

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Introduction

Receiving a file type parameter from HTML/JSP into a servlet can be a tricky process. It requires knowledge of the servlet API, HTML, and JSP. This tutorial will provide a step-by-step guide on how to receive a file type parameter from HTML/JSP into a servlet. It will cover the necessary steps to ensure that the file type parameter is properly received and handled. Additionally, it will provide tips and best practices to ensure that the process is as efficient and secure as possible.

Solution

The following code snippet shows how to receive a file type parameter from HTML/JSP into a servlet:

// Get the file parameter from the HTML/JSP page
String fileName = request.getParameter(“file”);

// Create a File object from the file parameter
File file = new File(fileName);

// Read the file contents into a byte array
byte[] fileData = Files.readAllBytes(file.toPath());

// Set the file data as an attribute in the request
request.setAttribute(“fileData”, fileData);


After painstaking efforts and google search I found a solution to my problem. A page from Stackoverflow helped very much. First I changed the get method of my form to post like this 

<form action="Upload" method="post" enctype="multipart/form-data">
    Image<input type="file" name="image" id="image" accept="image/jpg">
    <input type="submit" value="submit">
</form>

Then I wrote the following servlet code. We accept the <input type="file">data as Part data in servlet. Then we convert it to input stream. The input stream then can be saved in database. Here is my Servlet:-

package controller;

import java.io.IOException;
import java.io.InputStream;
import java.io.PrintWriter;
import java.nio.file.Path;
import java.nio.file.Paths;
import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.SQLException;
import javax.servlet.ServletException;
import javax.servlet.annotation.MultipartConfig;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.Part;
import model.ConnectionManager;

@MultipartConfig(location="/tmp", fileSizeThreshold=1048576, maxFileSize=20848820, maxRequestSize=418018841)
public class Upload extends HttpServlet {

    @Override
    protected void doPost(HttpServletRequest request, HttpServletResponse response)
            throws ServletException, IOException {
        Part filePart=request.getPart("image");`// Retrieves <input type="file" name="image">`
        String filePath = filePart.getSubmittedFileName();//Retrieves complete file name with path and directories 
        Path p = Paths.get(filePath); //creates a Path object
        String fileName = p.getFileName().toString();//Retrieves file name from Path object
        InputStream fileContent = filePart.getInputStream();//converts Part data to input stream

        Connection conn=ConnectionManager.getConnection();
        int  len=(int) filePart.getSize();
        String query = ("insert into IMAGETABLE(ID,NAME,LENGTH,IMAGE) VALUES(?,?,?,?)");


        try {
            PreparedStatement pstmt = conn.prepareStatement(query);
            pstmt.setInt(1, 5);
            pstmt.setString(2, fileName);
            pstmt.setInt(3, len);
            pstmt.setBinaryStream(4, fileContent, len);
            success=pstmt.executeUpdate();
        } catch (SQLException ex) {
            System.out.println("Error : "+ex.getMessage());
        }finally{
            try{
                if(fileContent!=null)fileContent.close();
                if(conn!=null)conn.close();
            }catch(IOException | SQLException ex){
                System.out.println("Error : "+ex.getMessage());
            }
        }

    }

}

After execution, it does the job successfully. We accept the image from user and save it in database. Hope this solution will help all ?

solved How to receive a file type parameter from html/jsp into a servlet


Solved: How to Receive a File Type Parameter from HTML/JSP into a Servlet

When developing web applications, it is often necessary to pass a file type parameter from an HTML or JSP page to a servlet. This can be a tricky process, as the servlet needs to be able to interpret the file type parameter correctly. Fortunately, there are a few simple steps that can be taken to ensure that the servlet receives the file type parameter correctly.

Step 1: Set the Form Encoding Type

The first step is to set the form encoding type to “multipart/form-data”. This will ensure that the servlet is able to interpret the file type parameter correctly. To do this, add the following line of code to the HTML or JSP page:

<form enctype="multipart/form-data">

Step 2: Add the File Type Parameter

The next step is to add the file type parameter to the HTML or JSP page. This can be done by adding the following line of code:

<input type="file" name="file">

This will create an input field that allows the user to select a file. The name of the input field should be set to “file” so that the servlet can interpret the file type parameter correctly.

Step 3: Retrieve the File Type Parameter in the Servlet

The final step is to retrieve the file type parameter in the servlet. This can be done by using the getPart() method of the HttpServletRequest object. The following code snippet shows how this can be done:

Part filePart = request.getPart("file");

This will retrieve the file type parameter from the HTML or JSP page and store it in the filePart object. The servlet can then use this object to access the file type parameter.

By following these steps, it is possible to pass a file type parameter from an HTML or JSP page to a servlet. This can be a tricky process, but with the right steps, it can be done successfully.