How to Upload File to Tomcat Server

Servlets - File Uploading

A Servlet tin be used with an HTML grade tag to permit users to upload files to the server. An uploaded file could be a text file or image file or any document.

Creating a File Upload Form

The following HTM code below creates an uploader form. Post-obit are the of import points to be noted downwardly −

The form method attribute should exist ready to Post method and GET method tin can non exist used
The form enctype aspect should be set to multipart/class-data.
The form activity aspect should be set to a servlet file which would handle file uploading at backend server. Post-obit example is using UploadServlet servlet to upload file.
To upload a single file you should use a single <input .../> tag with aspect blazon="file". To allow multiple files uploading, include more than one input tags with different values for the proper noun attribute. The browser associates a Browse button with each of them.

          <html>    <head>       <title>File Uploading Form</title>    </head>        <body>       <h3>File Upload:</h3>       Select a file to upload: <br />       <form activeness = "UploadServlet" method = "post" enctype = "multipart/form-data">          <input type = "file" proper noun = "file" size = "l" />          <br />          <input type = "submit" value = "Upload File" />       </form>    </body> </html>

This will display following result which would allow to select a file from local PC and when user would click at "Upload File", form would exist submitted forth with the selected fil −

          File Upload:          Select a file to upload:          
                    
                    
          NOTE: This is just dummy course and would not work.

Writing Backend Servlet

Following is the servlet UploadServlet which would take care of accepting uploaded file and to shop it in directory <Tomcat-installation-directory>/webapps/data. This directory name could also be added using an external configuration such as a context-param element in web.xml every bit follows −

          <web-app>    ....    <context-param>        <description>Location to shop uploaded file</description>        <param-name>file-upload</param-name>        <param-value>          c:\apache-tomcat-v.five.29\webapps\data\       </param-value>     </context-param>    .... </spider web-app>

Following is the source code for UploadServlet which tin handle multiple file uploading at a time. Before proceeding you have make sure the followings −

Following example depends on FileUpload, and then make sure you have the latest version of commons-fileupload.x.x.jar file in your classpath. You can download it from https://eatables.apache.org/fileupload/.
FileUpload depends on Commons IO, so make certain you have the latest version of commons-io-x.x.jar file in your classpath. You can download information technology from https://commons.apache.org/io/.
While testing following case, you should upload a file which has less size than maxFileSize otherwise file would not exist uploaded.
Make certain y'all have created directories c:\temp and c:\apache-tomcat8.0.28\webapps\information well in advance.

// Import required java libraries import java.io.*; import coffee.util.*;   import javax.servlet.ServletConfig; import javax.servlet.ServletException; import javax.servlet.http.HttpServlet; import javax.servlet.http.HttpServletRequest; import javax.servlet.http.HttpServletResponse;   import org.apache.commons.fileupload.FileItem; import org.apache.commons.fileupload.FileUploadException; import org.apache.commons.fileupload.disk.DiskFileItemFactory; import org.apache.commons.fileupload.servlet.ServletFileUpload; import org.apache.commons.io.output.*;  public class UploadServlet extends HttpServlet {        private boolean isMultipart;    private Cord filePath;    private int maxFileSize = 50 * 1024;    private int maxMemSize = four * 1024;    private File file ;     public void init( ){       // Go the file location where it would exist stored.       filePath = getServletContext().getInitParameter("file-upload");     }        public void doPost(HttpServletRequest request, HttpServletResponse response)       throws ServletException, java.io.IOException {           // Bank check that we have a file upload asking       isMultipart = ServletFileUpload.isMultipartContent(asking);       response.setContentType("text/html");       java.io.PrintWriter out = response.getWriter( );           if( !isMultipart ) {          out.println("<html>");          out.println("<head>");          out.println("<title>Servlet upload</championship>");            out.println("</head>");          out.println("<body>");          out.println("<p>No file uploaded</p>");           out.println("</body>");          out.println("</html>");          return;       }          DiskFileItemFactory mill = new DiskFileItemFactory();           // maximum size that will be stored in memory       factory.setSizeThreshold(maxMemSize);           // Location to save data that is larger than maxMemSize.       factory.setRepository(new File("c:\\temp"));        // Create a new file upload handler       ServletFileUpload upload = new ServletFileUpload(factory);           // maximum file size to be uploaded.       upload.setSizeMax( maxFileSize );        try {           // Parse the request to get file items.          Listing fileItems = upload.parseRequest(request); 	          // Procedure the uploaded file items          Iterator i = fileItems.iterator();           out.println("<html>");          out.println("<head>");          out.println("<title>Servlet upload</title>");            out.println("</head>");          out.println("<body>");              while ( i.hasNext () ) {             FileItem fi = (FileItem)i.next();             if ( !fi.isFormField () ) {                // Get the uploaded file parameters                String fieldName = fi.getFieldName();                String fileName = fi.getName();                String contentType = fi.getContentType();                boolean isInMemory = fi.isInMemory();                long sizeInBytes = fi.getSize();                             // Write the file                if( fileName.lastIndexOf("\\") >= 0 ) {                   file = new File( filePath + fileName.substring( fileName.lastIndexOf("\\"))) ;                } else {                   file = new File( filePath + fileName.substring(fileName.lastIndexOf("\\")+one)) ;                }                fi.write( file ) ;                out.println("Uploaded Filename: " + fileName + "<br>");             }          }          out.println("</body>");          out.println("</html>");          } grab(Exception ex) {             System.out.println(ex);          }       }              public void doGet(HttpServletRequest request, HttpServletResponse response)          throws ServletException, java.io.IOException {           throw new ServletException("GET method used with " +             getClass( ).getName( )+": POST method required.");       }    } }

Compile and Running Servlet

Compile to a higher place servlet UploadServlet and create required entry in web.xml file equally follows.

          <servlet>    <servlet-name>UploadServlet</servlet-name>    <servlet-course>UploadServlet</servlet-class> </servlet>  <servlet-mapping>    <servlet-proper name>UploadServlet</servlet-name>    <url-blueprint>/UploadServlet</url-design> </servlet-mapping>

Now effort to upload files using the HTML form which you created above. When you lot would endeavour http://localhost:8080/UploadFile.htm, it would display post-obit result which would assistance you uploading whatever file from your local automobile.

File Upload:

Select a file to upload:

If your servlet script works fine, your file should be uploaded in c:\apache-tomcat8.0.28\webapps\data\ directory.