以下是一個事例：

import java.util.regex.Matcher;
import java.util.regex.Pattern;

public class MessyCodeCheck {

	public static boolean isChinese(char c) {
		Character.UnicodeBlock ub = Character.UnicodeBlock.of(c);
		return ub == Character.UnicodeBlock.CJK_UNIFIED_IDEOGRAPHS
				|| ub == Character.UnicodeBlock.CJK_COMPATIBILITY_IDEOGRAPHS
				|| ub == Character.UnicodeBlock.CJK_UNIFIED_IDEOGRAPHS_EXTENSION_A
				|| ub == Character.UnicodeBlock.GENERAL_PUNCTUATION
				|| ub == Character.UnicodeBlock.CJK_SYMBOLS_AND_PUNCTUATION
				|| ub == Character.UnicodeBlock.HALFWIDTH_AND_FULLWIDTH_FORMS;
	}

	/**
	 *判斷字串是否為亂碼
	 * @param strName
	 * @return
	 */
	public static boolean isMessyCode(String strName) {
		Pattern p = Pattern.compile("\\s*|\t*|\r*|\n*");
		Matcher m = p.matcher(strName);
		String after = m.replaceAll("");
		String temp = after.replaceAll("\\p{P}", "");
		char[] ch = temp.trim().toCharArray();
		float chLength = ch.length;
		float count = 0;
		for (char c : ch) {
			if (!Character.isLetterOrDigit(c)) {
				if (!isChinese(c)) {
					count = count + 1;
					System.out.print(c);
				}
			}
		}
		float result = count / chLength;
		return result > 0.4;

	}

	public static void main(String[] args) {
		System.out.println(isMessyCode("*��JTP.jar�ļ����JTP�ļ���ȡ��ͼƬ��Դ"));
		System.out.println(isMessyCode("你好"));
		System.out.println(isMessyCode("123123adfasdfsa"));
		System.out.println(isMessyCode("123123a測試——@#￥%%dfasdfsa"));

		System.out.println(isMessyCode("*��JTP.jar�ļ����JTP�ļ���ȡ��ͼƬ��Դ"));
		System.out.println(isMessyCode("你好"));
		System.out.println(isMessyCode("123123adfasdfsa"));
		System.out.println(isMessyCode("123123a測試——@#￥%%dfasdfsa"));
	}
}