Compare two files using Java

The program will prompt for 2 file names(.txt) that are to be compared. Given the file names, this program will compare the two files.

If any difference is there, it will print the differences and no. of differences in command prompt. 

If no difference is there, it will print

"files are equal".

import java.io.*;
import java.util.*;

//defining class

public class myfilereader
{
//defining main function
 public static void main (String[] args) throws java.io.IOException
    {
  //Getting the name of the files to be compared.
  BufferedReader br2 = new BufferedReader (new
InputStreamReader(System.in));
  System.out.println("Enter 1st File name:");
    String str = br2.readLine();
    System.out.println("Enter 2nd File name:");
    String str1 = br2.readLine();

  String s1="";
    String s2="",s3="",s4="";
    String y="",z="";

        //Reading the contents of the files
   BufferedReader br = new BufferedReader (new FileReader (str));
    BufferedReader br1 = new BufferedReader (new FileReader (str1));

   while((z=br1.readLine())!=null)
    s3+=z;

  while((y=br.readLine())!=null)
     s1+=y;

  System.out.println ();

        //String tokenizing
    int numTokens = 0;
    StringTokenizer st = new StringTokenizer (s1);
    String[] a = new String[10000];
    for(int l=0;l<10000;l++)
      {a[l]="";}
    int i=0;
    while (st.hasMoreTokens())
      {
        s2 = st.nextToken();
          a[i]=s2;
   i++;
            numTokens++;
      }

      int numTokens1 = 0;
     StringTokenizer st1 = new StringTokenizer (s3);
     String[] b = new String[10000];
     for(int k=0;k<10000;k++)
      {b[k]="";}
     int j=0;
     while (st1.hasMoreTokens())
       {
        s4 = st1.nextToken();
        b[j]=s4;
        j++;
        numTokens1++;
       }

//comparing the contents of the files and printing the differences, if any.
  int x=0;
      for(int m=0;m<a.length;m++)
      {
   if(a[m].equals(b[m])){}
    else
    {
     x++;
  System.out.println(a[m] + " -- " +b[m]);
  System.out.println();}
      }
 System.out.println("No. of differences : " + x);
 if(x>0){System.out.println("Files are not equal");}
 else{System.out.println("Files are equal. No difference found");}

 }
}

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Jasper report as pdf

prints the report in pdf format.

//import it in the java file

import net.sf.jasperreports.engine.JasperExportManager;
// a function ehich calls the jasper to generate the report
private String generatePldbbyCC(ParameterReportCriteria prcObject, Map reportMap) throws Exception {
 JasperPrint jasperPrint = null;
 JRFileVirtualizer virtualizer = null;
 String destFileLoc = null;
 File sourceFile = null;
 File destFile = null;
 ESpecDAOController control = new ESpecDAOController();
 // puts the parameters to jasper.
 parameters.put(Constants.COMPETITIVE_CATEGORIES, prcObject.getSelectedCompCategs()); 
 parameters.put("REPORT_CONNECTION", control.getMasterConnection());
 parameters.put(EspecConstants.CURR_TIME, "Exported: " + new SimpleDateFormat("M/d/yyyy 'at' hh:mm:ss a").format(DateUtil.getCurrentDateTime()));

 PropertiesVO templatePath = setJasperpath();

 virtualizer = new JRFileVirtualizer(1, templatePath.getValue());

 parameters.put(SUBREPORT_DIR, templatePath.getValue());

 parameters.put(JRParameter.REPORT_VIRTUALIZER, virtualizer);

 try {

  jasperPrint = JasperFillManager.fillReport(templatePath.getValue() + "/sample.jasper", parameters, control.getMasterConnection());

 } else {
  //get the file with extension as pdf
  destFile = new File(templatePath.getValue(), jasperPrint.getName() + "_" + prcObject.getProcessId() + ".pdf");

 } 

 destFileLoc = destFile.toString();
 //exports the report as pdf.
 JasperExportManager.exportReportToPdfFile(jasperPrint,destFileLoc);

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Finding the difference between two images using their samples

Helps in finding the difference between two images by obtaining their samples and comparing them. The number of bands assosiated with each image is also compared, along with their width and height.

File file1 = new File("C:\Documents and Settings\515956\Desktop\Raj_image.jpg"); 
File file2 = new File("C:\Documents and Settings\515956\Desktop\Local_image.jpg");  
BufferedImage image1 = ImageIO.read(file1); 
BufferedImage image2 = ImageIO.read(file2);

Raster r1 = image1.getData();
Raster r2 = image2.getData(); 
boolean ret; // Stores result. 
// Check image sizes and number of bands. If there are different
// then no need to compare images as they are definitely not equal. 

System.out.println("image1 band"+r1.getNumBands()+"  image2 band"+r2.getNumBands()+"  image1 width"+r1.getWidth()+"  image2 width"+ r2.getWidth()+"  image1 height"+ r1.getHeight()+"  image2 height"+r2.getHeight()); 

if (r1.getNumBands() != r2.getNumBands() ||   r1.getWidth() != r2.getWidth() ||   r1.getHeight() != r2.getHeight()) {  
 ret = false;
 System.out.println("Primary comparison failure");

} 

else {  
 // #Bands and image bounds match so compare each sample in turn. 
 ret = true;   
 search:   
  for (int i=0; i<r1.getNumBands(); ++i) { 
   for (int x=0; x<r1.getWidth(); ++x) {    
    for (int y=0; y<r1.getHeight(); ++y) {  


     if (r1.getSample(x, y, i) != r2.getSample(x, y, i)) {     
      // At least one sample differs so result is false; 
      ret = false; 
      System.out.println("sample difference");
      // Use labeled break to terminate all loops.
      break
      search;   
     }   
    }    
   }   
  }   

}
System.out.println(ret);

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Preventing CRLF injection

This code will encode your data if a user tries to attack your application through CRLF injection

String s=Arrays.toString(object);
if(s.contains("/") || s.contains(">")||s.contains("<")||s.contains("?") ||s.contains("&") ||s.contains(""))
{
 String validobject=URLEncoder.encode(s);
 System.out.println("the encoded data is"+validobject);
}
else
{
 System.out.println("the non-encoded data is"+object);
}

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Send a mail from SMTP server using Java Mail

This code allows the user to login to his/her mail account to send a mail to another recepient.First the code needs to be configured by entering the Server details and user credentials .This code authenticates the user and creates a session then a MimeMessage Object is created where the subject and content of the mail is set.

public class SmtpMail{
 public static void main(String[] args) 
 {
  Properties props = new Properties();
  props.put("mail.smtp.auth", "true");
  props.put("mail.smtp.starttls.enable", "true");
  props.put("mail.smtp.host", "smtp.gmail.com");
  props.put("mail.smtp.port", "587");
  final String username = "Username@gmail.com";
  final String password = "Password";
  Session session = Session.getInstance(props,
new javax.mail.Authenticator() {
 protected PasswordAuthentication getPasswordAuthentication() {
   return new PasswordAuthentication(username, password);
  }
  });
try {
   Message message = new MimeMessage(session);
   message.setRecipients(Message.RecipientType.TO,
    InternetAddress.parse("toEmailAddress@yahoo.com"));
   System.out.println(session.toString());
   message.setSubject("JavaMail Subject");
   message.setText("Dear Recepient,"
    + "\n\n This is a Test Mail");
   System.out.println(session.toString());
   Transport.send(message);
   System.out.println("Done");
 
  } catch (MessagingException e) {
   throw new RuntimeException(e);
  }
 }
}

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Creating JSON using Java

This is used to create JSON objects using Java

import org.json.JSONObject;
//Creating JSON object
JSONObject json = new JSONObject();
//Put tag name and value to the object
json.put("city", "Mumbai");
json.put("country", "India");

String output = json.toString();

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Getting Timezone based Timestamp

It is used to find the Timestamp based on the given Timezone

//Creating format based on the need
SimpleDateFormat dateFormat = new SimpleDateFormat("dd/MM/yyyy HH:mm:ss");
//Set the Timezone 
dateFormat.setTimeZone(clientTimeZone);
String clientTime = dateFormat.format(date);
Date date2 = new Date(clientTime);
//
System.out.println(date2);

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