Java OCR Web Project – Tesseract Optical Character Recoginition(OCR)

 This tutorial shows JAVA program which can be used to convert Image To Text pragmatically. First you have to install ‘tesseract-ocr-setup-3.02.02.exe’ in the location C:\Tesseract-OCR for this example.

1. Project Structure in Eclipse
   
2. You can update the location you installed the OCR here and the local host server information.
   Common_Things.java

   package common_things;
   public class Common_Things {
      public static String url="http://localhost:8080/OCR";
      public static String upload_path="C:\\Tesseract-OCR";
   }
   

3. This class does the CMD prompt commands to generate out put file after processing OCR. The output file is generated is C:\Tesseract-OCR by default. You can change it if you want in this class.
   create_file.java

   package OCR;
   import java.io.PrintWriter;
   public class create_file {
   	public void create_output_file(String file_name) {
   		String[] command =
   	    {
   	        "cmd",
   	    };
   	    Process p;
   		try {
   	    p = Runtime.getRuntime().exec(command);
   	    new Thread(new SyncPipe(p.getErrorStream(), System.err)).start();
   	    new Thread(new SyncPipe(p.getInputStream(), System.out)).start();
   	    PrintWriter stdin = new PrintWriter(p.getOutputStream());
   	    stdin.println("cd..");
   	    stdin.println("cd..");
   	    stdin.println("cd..");
   	    stdin.println("cd..");
   	    stdin.println("c:");
   	    stdin.println("cd..");
   	    stdin.println("cd..");
   	    stdin.println("cd..");
   	    stdin.println("cd Tesseract-OCR ");
   	    stdin.println("tesseract "+file_name+" "+file_name);
   	    stdin.close();
   	    int returnCode = p.waitFor();
   	   // System.out.println("Return code = " + returnCode);
   		} catch (Exception e) {
   			// TODO Auto-generated catch block
   			e.printStackTrace();
   		}
   	}
   }	
   

4. This class is for supporting CMD operations from JAVA program.
   SyncPipe.java

   package OCR;
   import java.io.InputStream;
   import java.io.OutputStream;
   class SyncPipe implements Runnable
   {
   public SyncPipe(InputStream istrm, OutputStream ostrm) {
         istrm_ = istrm;
         ostrm_ = ostrm;
     }
     public void run() {
         try
         {
             final byte[] buffer = new byte[1024];
             for (int length = 0; (length = istrm_.read(buffer)) != -1; )
             {
                 ostrm_.write(buffer, 0, length);
             }
         }
         catch (Exception e)
         {
             e.printStackTrace();
         }
     }
     private final OutputStream ostrm_;
     private final InputStream istrm_;
   }
   

5. This class uploads the image to process to the location specified in Common_Things.java, For us the location is C:\Tesseract-OCR
   FileUploadHandler.java

   package Upload_Data;
   import java.io.File;
   import java.io.IOException;
   import java.io.PrintWriter;
   import java.sql.Connection;
   import java.sql.PreparedStatement;
   import java.util.Iterator;
   import java.util.List;
   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.FileItemFactory;
   import org.apache.commons.fileupload.disk.DiskFileItemFactory;
   import org.apache.commons.fileupload.servlet.ServletFileUpload;
   import common_things.Common_Things;
   public class FileUploadHandler extends HttpServlet {
   	private static final long serialVersionUID = 1L;
   	public void doGet(HttpServletRequest request, HttpServletResponse response) throws IOException {
   		doPost(request, response);
   	}
   	public void doPost(HttpServletRequest request, HttpServletResponse response) throws IOException {
   		Connection connection=null;
   	  	PreparedStatement ps=null;
   	  	String file_name=null;
   	  	String file_name_given=null;
   		response.setContentType("text/html");
   		PrintWriter out = response.getWriter();
   		boolean isMultipartContent = ServletFileUpload.isMultipartContent(request);
   		if (!isMultipartContent) {
   			return;
   		}
   		FileItemFactory factory = new DiskFileItemFactory();
   		ServletFileUpload upload = new ServletFileUpload(factory);
   		try {
   			List fields = upload.parseRequest(request);
   			Iterator it = fields.iterator();
   			if (!it.hasNext()) {
   				return;
   			}
   			while (it.hasNext()) {
   				FileItem fileItem = it.next();
   				boolean isFormField = fileItem.isFormField();
   				if (isFormField) {
   					 if(file_name==null){
   			    		   if(fileItem.getFieldName().equals("file_name")){
   			    			   file_name=fileItem.getString();
   			    		   } 
   			    	   }
   					 if(file_name_given==null){
   			    		   if(fileItem.getFieldName().equals("file_name_given")){
   			    			   file_name_given=fileItem.getString();
   			    		   } 
   			    	   }
   				} else {
   	    	    	  if(fileItem.getSize()>0){
   	    	    		  file_name=fileItem.getName();
   	    	    		  fileItem.write( new File(Common_Things.upload_path + File.separator + fileItem.getName()));
   	    	    	  }
   				}
   			}
   		} catch (Exception e) {
   			e.printStackTrace();
   		}finally{
   			if(connection!=null){
   				try {
   						connection.close();
   						System.out.println("connection closed");
   					}
   				 catch (Exception e2) {
   					e2.printStackTrace();
   				}
   			}
   			if(ps!=null){
   				try {
   					ps.close();
   					}
   				 catch (Exception e2) {
   					 e2.printStackTrace();
   				}
   			}
   			out.println("");
   			out.close();
   		}
   	}
   }
   

6. 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">
   	<display-name>
   	OCR</display-name>
   	<welcome-file-list>
   	<welcome-file>index.html</welcome-file>
   		<welcome-file>index.htm</welcome-file>
   		<welcome-file>index.jsp</welcome-file>
   		<welcome-file>default.html</welcome-file>
   		<welcome-file>default.htm</welcome-file>
   		<welcome-file>default.jsp</welcome-file>
   	</welcome-file-list>
   	<servlet>
   		<servlet-name>FileUploadHandler</servlet-name>
   		<servlet-class>Upload_Data.FileUploadHandler</servlet-class>
   	</servlet>
   	<servlet-mapping>
   		<servlet-name>FileUploadHandler</servlet-name>
   		<url-pattern>/FileUploadHandler/*</url-pattern>
   	</servlet-mapping>
   </web-app>
   

7. index.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">
   <%@page import="common_things.Common_Things"%><html>
   <head>
   <meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1">
   <!-- meta -->
   <meta charset="utf-8">
   </head>
   <body>
         <form action="<%=Common_Things.url %>/FileUploadHandler/" enctype="multipart/form-data" method="post">
               Select<input type="file" name="file2" /><br>
               File name <input type="text" name="file_name_given"> <br><br>
               <input type="submit" value="upload" />
         </form>
   </body>
   </html>
   

8. read.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">
   <%@page import="common_things.Common_Things"%>
   <%@page import="OCR.create_file"%>
   <%@page import="OCR.read_file"%><html>
   <head>
   <meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1">
   <!-- meta -->
   <meta charset="utf-8">
   </head>
   <body>
        <%
        String file_name=(String)request.getParameter("file_name");
        String file_name_given=(String)request.getParameter("file_name_given");
        //creating the out put file after upload and reading
        create_file obj_create_file=new create_file();
        obj_create_file.create_output_file(file_name);
        //read the created out put file
        read_file obj_read_file=new read_file();
        String read=obj_read_file.read_file(file_name);
        %>
        <%=file_name %><br>
        <%=file_name_given %><br>
        <br>
        <br>
        <hr>
        <%=read %>
        <hr>
        <br><br>
        <br><br><br>
        read success!!...
   </body>
   </html>