Code Recipes Blog

In this post under Apache Commons IO, I will show with example the easiest way to compare whether contents of two files are equal or not.

Apache Commons “IOUtils” class provide a static method called “contentEquals” which compare contents of two file and return a boolen.

Below is the complete main code

Main class

package ioutils;

import org.apache.commons.io.IOUtils;

import java.io.File;
import java.io.FileReader;
import java.io.IOException;

public class Example2 {
    public static void main(String[] args) throws IOException {
        File file1 = new File("Quotes1.txt");
        File file2 = new File("Quotes2.txt");
        File file3 = new File("Quotes3.txt");
        try(FileReader fileReader1 = new FileReader(file1);
            FileReader fileReader2 = new FileReader(file2);
            FileReader fileReader3 = new FileReader(file3)) {
            boolean equals = IOUtils.contentEquals(fileReader1, fileReader2);
            System.out.println("Quotes1 equals Quotes2: " + equals);
            equals = IOUtils.contentEquals(fileReader2, fileReader3);
            System.out.println("Quotes2 equals Quotes3: " + equals);
        }
    }
}

In the above code at line 11, 12, 13 I create three “File” instances one for “Quotes1.txt” file, second for “Quotes2.txt”, and third for “Quotes3.txt” file.

In the try-with-resource block, I create three “FileReader” instances one for each “File” instances.

At line 17, I call “contentEquals” method of “IOUtils” class and pass two instances of “FileReader” class as method argument.

The “contentEquals” method will compare the contents of the two file and return a boolean value.

In this way we can check whether contents of two files are equal or not.