String str = "Hello, UtilCode";
boolean isNullOrEmpty = StringUtil.isNullOrEmpty(str);
Date now = new Date();
String formattedDate = DateUtil.format(now, "yyyy-MM-dd HH:mm:ss");
Date nextDay = DateUtil.addDays(now, 1);
String sourceFile = "path/to/source/file.txt";
String targetFile = "path/to/target/folder/file.txt";
FileUtil.copy(sourceFile, targetFile);
String url = "http://www.example.com/api/data";
String response = HttpUtil.get(url);
String plaintext = "Hello, UtilCode";
String encryptedText = EncryptUtil.md5(plaintext);
String str = "123";
int num = ConvertUtil.toInt(str);
