java中^的使用

  if (true ^ true) {
            System.out.println("全為真？");
        }
        if (false ^ false) {
            System.out.println("全為假");
        }
        if (false ^ true) {
            System.out.println("有一個為真");
        }
//有一個為真

 public static boolean contentEquals(final File file1, final File file2) throws IOException {
        if (file1 == null && file2 == null) {
            return true;
        }
        if (file1 == null ^ file2 == null) {
            return false;
        }
        final boolean file1Exists = file1.exists();
        if (file1Exists != file2.exists()) {
            return false;
        }

        if (!file1Exists) {
            // two not existing files are equal
            return true;
        }

        if (file1.isDirectory() || file2.isDirectory()) {
            // don‘t want to compare directory contents
            throw new IOException("Can‘t compare directories, only files");
        }

        if (file1.length() != file2.length()) {
            // lengths differ, cannot be equal
            return false;
        }

        if (file1.getCanonicalFile().equals(file2.getCanonicalFile())) {
            // same file
            return true;
        }

        try (InputStream input1 = new FileInputStream(file1);
             InputStream input2 = new FileInputStream(file2)) {
            return IOUtils.contentEquals(input1, input2);
        }
    }