Java simulates PHP's pack and unpack classes unpack download unpretty rapstar struct.unpack

The example in this article shares with you the specific code of Java's simulation of PHP's pack and unpack classes for your reference. The specific content is as follows

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 <= '9') {
          n -= '0';
        } else if (n >= 'A' && n <= 'F') {
          n -= ('A' - 10);
        } else if (n >= 'a' && n <= 'f') {
          n -= ('a' - 10);
        } else {
          continue;
        }
        output[position] |= (n << nibbleshift);
 
        if (nibbleshift == 0) {
          position++;
        }
        nibbleshift = (nibbleshift + 4) & 7;
      }
 
      return output;
    }
 
    /**
     * 16进制的字符解压 类php中unpack
     *
     * @param is
     * @param len
     * @return
     * @throws IOException
     */
    public static String unpack(InputStream is, int len) throws IOException {
      byte[] bytes = new byte[len];
      is.read(bytes);
      return unpack(bytes);
    }
 
    /***
     * 16进制的字符解压 类php中unpack
     * @param bytes
     * @return
     */
    public static String unpack(byte[] bytes) {
      StringBuilder stringBuilder = new StringBuilder("");
      if (bytes == null || bytes.length <= 0) {
        return null;
      }
      for (int i = 0; i < bytes.length; i++) {
        int v = bytes[i] & 0xFF;
        String hv = Integer.toHexString(v);
        if (hv.length() < 2) {
          stringBuilder.append(0);
        }
        stringBuilder.append(hv);
      }
      return stringBuilder.toString();
    }
  }

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