比较两个文件并用Java进行总结

Question

I have 2 txt file and both have some different data. And I am comparing both then summarize report for where and change has done. But my code is running for only 1 line for both file:

Input

v1.txt:

  ABCD DEFG
  XYZ AAA
  NNN

v2.txt:

  ABCD DEF
  XYZ AAA
  NN

Output what i have received: Two files have different content.

They differ at line 1
File1 has ABCD DEFG and File2 has ABCD DEF at line 1

Code:

import java.io.BufferedReader;
import java.io.FileReader;
import java.io.IOException;

public class CompareTextFiles {
    public static void main(String[] args) throws IOException {
        BufferedReader reader1 = new BufferedReader(new FileReader("Data\v1.txt"));
        BufferedReader reader2 = new BufferedReader(new FileReader("Data\v2.txt"));
        String line1 = reader1.readLine();
        String line2 = reader2.readLine();
        boolean areEqual = true;
        int lineNum = 1;
        while (line1 != null || line2 != null) {
            if (line1 == null || line2 == null) {
                areEqual = false;
                break;
            } else if (!line1.equalsIgnoreCase(line2)) {
                areEqual = false;
                break;
            }
            line1 = reader1.readLine();
            line2 = reader2.readLine();
            lineNum++;
        }
        if (areEqual) {
            System.out.println("Two files have same content.");
        } else {
            System.out.println("Two files have different content. They differ at line " + lineNum);
            System.out.println("File1 has " + line1 + " and File2 has " + line2 + " at line " + lineNum);
        }
        reader1.close();
        reader2.close();
    }
}

Answer 1

Here is the code that has been revised and formatted.

import java.io.BufferedReader; 
import java.io.FileReader; 
import java.io.IOException; 

public class CompareTextFiles {
    public static void main(String[] args) throws IOException { 
        BufferedReader reader1 = new BufferedReader(new FileReader("Data\v1.txt")); 
        BufferedReader reader2 = new BufferedReader(new FileReader("Data\v2.txt")); 
        String line1 = reader1.readLine(); 
        String line2 = reader2.readLine(); 
        boolean areEqual = true; 
        int lineNum = 1; 
        while (line1 != null || line2 != null) { 
            if (line1 == null || line2 == null) { 
                areEqual = false; 
                break; 
            } else if (!line1.equalsIgnoreCase(line2)) { 
                System.out.println("Two files have different content at line " + lineNum); 
                System.out.println("File1 has " + line1 + " and File2 has " + line2 + " at line " + lineNum); 

            } 
            line1 = reader1.readLine(); 
            line2 = reader2.readLine(); 
            lineNum++; 
        } 

        reader1.close(); 
        reader2.close(); 
    } 
}

The changes I have done:

1. Moved the if condition from after the loop to inside the loop so it prints out each line that is different.
2. Changed the wording of the System.out.
3. Removed the break; from the if condition where the lines are not equal.