Tung.java

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package common;

import java.io.BufferedReader;
import java.io.File;
import java.io.FileNotFoundException;
import java.io.FileReader;
import java.io.FileWriter;
import java.io.IOException;
import java.io.PrintWriter;

public class NewClass {
        public static void main(String[] args) {
            NewClass rlf = new NewClass();
            rlf.removeLineFromFile("E:\\test.txt", "123");
        }
    
        public void removeLineFromFile(String file, String lineToRemove) {
            try {
                File inFile = new File(file);
    
                if (!inFile.isFile()) {
                    System.out.println("Parameter is not an existing file");
                    return;
                }
    
                //Construct the new file that will later be renamed to the original filename.
                File tempFile = new File(inFile.getAbsolutePath() + ".txt");
    
                BufferedReader br = new BufferedReader(new FileReader(file));
                PrintWriter pw = new PrintWriter(new FileWriter(tempFile));
    
                String line = null;
    
                //Read from the original file and write to the new
                //unless content matches data to be removed.
                while ((line = br.readLine()) != null) {
                    
                    String[] arr = line.split("=");
                    
                    for (String i : arr) {
                           
                        if (!i.trim().equals(lineToRemove)) {
    
                            pw.println(i);
                            pw.flush();
                        }
                    }
                }
                pw.close();
                br.close();
    
                //Delete the original file
                if (!inFile.delete()) {
                    System.out.println("Could not delete file");
                    return;
                }
    
                //Rename the new file to the filename the original file had.
                if (!tempFile.renameTo(inFile)) System.out.println("Could not rename file");
    
            }
            catch (FileNotFoundException ex) {
                ex.printStackTrace();
            }
            catch (IOException ex) {
                ex.printStackTrace();
            }
        }
    }