Replacing String In File

Hi Reader,

It's going to be my second post.
This post is not as a rocket science but needful.
I got idea to create this program, when i got issue with my module.
There was an xml document and i need to know the occurances of a particular string.
The file size was more than 10 mb. I used edit plus for this. First it took time for loading file in edit plus and then when i tried hit "ctrl + h" (to find and replacce dialog box) duhh! Got hanged.
Then i used my program. And felt glad.

Please have look may be it ll be helpful for you also.

This program replaces all the occurances of a given string to be replaced in the given file with the given string to be replaced by.

view plainprint?

1.   package src;  
2.   import java.io.BufferedReader;  
3.   import java.io.BufferedWriter;  
4.   import java.io.File;  
5.   import java.io.FileReader;  
6.   import java.io.FileWriter;  
7.   import java.io.IOException;  
8.   
9.   public class ReplaceDataInFile {  
10.      public static void main(String args[]) {  
11.      ReplaceDataInFile ob = new ReplaceDataInFile();  
12.      ob.replaceStringInFile("C:\\_T_Work", "file.txt", "old", "new");  
13.   }  
14.   
15.   
16. <div align="left">  private void replaceStringInFile(final String fileLoc, final String fileName, final String toReplace, final String replaceBy) {  
17.   
18.     File file = null;  
19.     BufferedReader br = null;   
20.     BufferedWriter bw = null;  
21.     String currentLine = "";  
22.     String oldContentOfFile = "";  
23.     int occuranceFound = 0;  
24.     int countLine = 0;</div><div align="left">  
25.   
26.     try {  
27.       file = new File(fileLoc + System.getProperty("file.separator") + fileName);  
28.       br = new BufferedReader(new FileReader(file));  
29.         
30.       while ((currentLine = br.readLine()) != null) {  
31.         countLine++;  
32.         oldContentOfFile = oldContentOfFile + currentLine + "\r\n";  
33.         System.out.println("Line " + countLine + " : " + currentLine);  
34.   
35.         if (currentLine.contains(toReplace)) {  
36.           occuranceFound++;  
37.         }  
38.       }</div><div align="left">  
39.     } catch (IOException e) {  
40.          System.out.println("Error Occured When Reading File : " + e);  
41.          System.exit(1);  
42.     } finally {  
43.          if (br != null) {  
44.            try {  
45.              br.close();  
46.            } catch (IOException e) {  
47.                System.out.println("Error Occured When Closing Reader : " + e);  
48.                System.exit(1);  
49.            }  
50.          }  
51.      }</div><div align="left">  
52.   
53.      System.out.println();  
54.      System.out.println("Old Content of The File : ");  
55.      System.out.println(oldContentOfFile);  
56.   
57.      String latestText = oldContentOfFile.replaceAll(toReplace, replaceBy);  
58.      System.out.println("Latest Content of The File : ");  
59.      System.out.println(latestText);</div><div align="left">  
60.   
61.      try {  
62.      bw = new BufferedWriter(new FileWriter(fileLoc + System.getProperty("file.separator") + fileName));  
63.      bw.write(latestText);  
64.      System.out.println("Total [" + occuranceFound + "] Occurances of ["  
65. + toReplace + "] Replaced By [" + replaceBy + "].");  
66.      } catch (IOException e) {  
67.          System.out.println("Error Occured When Writtin To File : " + e);  
68.      } finally {  
69.         if (bw != null) {  
70.           try {  
71.             bw.close();  
72.           } catch (IOException e) {  
73.               System.out.println("Error Occured When Closing Writer : " + e);  
74.               System.exit(1);  
75.           }  
76.         }  
77.     }  
78.   }  
79. }</div>  

  package src;
  import java.io.BufferedReader;
  import java.io.BufferedWriter;
  import java.io.File;
  import java.io.FileReader;
  import java.io.FileWriter;
  import java.io.IOException;

  public class ReplaceDataInFile {
     public static void main(String args[]) {
     ReplaceDataInFile ob = new ReplaceDataInFile();
     ob.replaceStringInFile("C:\\_T_Work", "file.txt", "old", "new");
  }


  private void replaceStringInFile(final String fileLoc, final String fileName, final String toReplace, final String replaceBy) {

    File file = null;
    BufferedReader br = null; 
    BufferedWriter bw = null;
    String currentLine = "";
    String oldContentOfFile = "";
    int occuranceFound = 0;
    int countLine = 0;


    try {
      file = new File(fileLoc + System.getProperty("file.separator") + fileName);
      br = new BufferedReader(new FileReader(file));
      
      while ((currentLine = br.readLine()) != null) {
        countLine++;
        oldContentOfFile = oldContentOfFile + currentLine + "\r\n";
        System.out.println("Line " + countLine + " : " + currentLine);

        if (currentLine.contains(toReplace)) {
          occuranceFound++;
        }
      }

    } catch (IOException e) {
         System.out.println("Error Occured When Reading File : " + e);
         System.exit(1);
    } finally {
         if (br != null) {
           try {
             br.close();
           } catch (IOException e) {
               System.out.println("Error Occured When Closing Reader : " + e);
               System.exit(1);
           }
         }
     }


     System.out.println();
     System.out.println("Old Content of The File : ");
     System.out.println(oldContentOfFile);

     String latestText = oldContentOfFile.replaceAll(toReplace, replaceBy);
     System.out.println("Latest Content of The File : ");
     System.out.println(latestText);


     try {
     bw = new BufferedWriter(new FileWriter(fileLoc + System.getProperty("file.separator") + fileName));
     bw.write(latestText);
     System.out.println("Total [" + occuranceFound + "] Occurances of ["
+ toReplace + "] Replaced By [" + replaceBy + "].");
     } catch (IOException e) {
         System.out.println("Error Occured When Writtin To File : " + e);
     } finally {
        if (bw != null) {
          try {
            bw.close();
          } catch (IOException e) {
              System.out.println("Error Occured When Closing Writer : " + e);
              System.exit(1);
          }
        }
    }
  }
}

To execute this just change the paramter of the method called in main().

Waiting for your responses.

Thanks,
Tanzy.