Java - รบกวนสอบถาม และวิธีการ หากเราต้องการอ่านไฟล์และเปรียบเทียบข้อมูลแต่ละบรรทัดเหมือนกันหรือไม่

import java.io.BufferedReader;
import java.io.File;
import java.io.FileReader;
import java.util.ArrayList;

public class LineCompare {
	
	public static void main(String[] args){
		try{
			File file = new File("c:/temp/myfile.txt");
			BufferedReader reader = new BufferedReader(new FileReader(file));
			String line = null;
			ArrayList<String> allLineArray = new ArrayList<String>();
			while ( (line=reader.readLine()) != null){
				allLineArray.add(line);
			}
			reader.close();
			String firstLine = allLineArray.get(0);
			for (int i=1;i<allLineArray.size();i++){
				String nextLine = allLineArray.get(i);
				if (firstLine.equals(nextLine)){
					System.out.println("Line#1 duplcate with line#"+i);
				}
			}
		}
		catch(Exception ex){
			ex.printStackTrace();
		}
	}
}

import java.io.IOException;
import java.io.LineNumberReader;
import java.io.Reader;
import java.util.List;


public class Diff
{
    public static void readersAsText(Reader r1, String name1, Reader r2, String name2,
        List diffs)
        throws IOException
    {
        LineNumberReader reader1 = new LineNumberReader(r1);
        LineNumberReader reader2 = new LineNumberReader(r2);
        String line1 = reader1.readLine();
        String line2 = reader2.readLine();
        while (line1 != null && line2 != null)
        {
            if (!line1.equals(line2))
            {
                diffs.add("File \"" + name1 + "\" and file \"" +
                    name2 + "\" differ at line " + reader1.getLineNumber() +
                    ":" + "\n" + line1 + "\n" + line2);
                break;
            }
            line1 = reader1.readLine();
            line2 = reader2.readLine();
        }
        if (line1 == null && line2 != null)
            diffs.add("File \"" + name2 + "\" has extra lines at line " +
                reader2.getLineNumber() + ":\n" + line2);
        if (line1 != null && line2 == null)
            diffs.add("File \"" + name1 + "\" has extra lines at line " +
                reader1.getLineNumber() + ":\n" + line1);
    }
}

import java.io.FileReader;
import java.io.Reader;
import java.util.ArrayList;
import java.util.List;

public class CallDiff {
	public static void main(String[] args){
		try{
			String fileName1 = "c:/temp/file1.txt";
			String fileName2 = "c:/temp/file2.txt";
			Reader reader1 = new FileReader(fileName1);
			Reader reader2 = new FileReader(fileName1);
			List<String> diffResult = new ArrayList<String>();
			Diff.readersAsText(reader1, fileName1, reader2, fileName2, diffResult);
			for (String result : diffResult){
				System.out.println(result+"\n");
			}
		}
		catch(Exception ex){
			ex.printStackTrace();			
		}
	}
}

import java.io.BufferedReader;
import java.io.File;
import java.io.FileReader;
import java.util.ArrayList;

public class LineCompare {
	static ArrayList<String[]> allPattens = new ArrayList<String[]>();

	public static void main(String[] args) {
		try {
			File file = new File("c:/windows/temp/ip_log.txt");
			BufferedReader reader = new BufferedReader(new FileReader(file));
			String line = null;

			int lineNo = 0;
			while ((line = reader.readLine()) != null) {
				lineNo++;
				String[] values = line.split(" ");
				if (!isSame(values)) {
					System.out.println("line#" + lineNo + "=>" + line);
					allPattens.add(values);
				}
			}
			reader.close();
		} catch (Exception ex) {
			ex.printStackTrace();
		}
	}

	public static boolean isSame(String[] values) {
		boolean same = false;
		if (allPattens == null || allPattens.size() <= 0) {
			return false;
		}
		for (String[] patterns : allPattens) {
			if (patterns.length != values.length) {
				continue;
			}
			int sameCount = 0;
			for (int i = 0; i < patterns.length; i++) {
				for (int j = 0; j < values.length; j++) {
					if (patterns[i].equals(values[j])) {
						sameCount++;
					}
				}
			}
			if (sameCount == patterns.length) {
				return true;
			}
		}
		return same;
	}
}