要生成一个摘要，需要使用MessageDigest类来计算哈希值。以下是一个使用SHA-256算法生成摘要的示例代码： ```java import java.security.MessageDigest; import java.security.NoSuchAlgorithmException; public class Main { public static void main(String[] args) { try { String input = "Android 4.4.4"; MessageDigest digest = MessageDigest.getInstance("SHA-256"); byte[] hash = digest.digest(input.getBytes()); // Convert byte array to hexadecimal string StringBuilder hexString = new StringBuilder(); for (byte b : hash) { String hex = Integer.toHexString(0xff & b); if (hex.length() == 1) { hexString.append('0'); } hexString.append(hex); } System.out.println("Generated hash: " + hexString.toString()); } catch (NoSuchAlgorithmException e) { e.printStackTrace(); } } } 
