java模拟PHP的pack和unpack类_php技巧

package qghl.intp.util;
 
import java.io.IOException;
import java.io.InputStream;
 
public class PackUtil{
 
    /**
     * 打包字符串
     * 类似php中pack在java中的实现
     *
     * @param str
     * @return
     */
    public static byte[] pack(String str) {
      int nibbleshift = 4;
      int position = 0;
      int len = str.length() / 2 + str.length() % 2;
      byte[] output = new byte[len];
      for (char v : str.toCharArray()) {
        byte n = (byte) v;
        if (n >= '0' && n = 'A' && n = 'a' && n