package com.test.util;
import java.io.ByteArrayInputStream; import java.io.DataInputStream; import java.io.IOException; import java.nio.ByteBuffer; import java.nio.ByteOrder; import java.security.MessageDigest; import java.security.NoSuchAlgorithmException; import java.util.Arrays;
public class TestHCL { public static byte[] getMD5(byte[] source) { if(source == null ) { return null; } try { MessageDigest md = MessageDigest.getInstance("MD5"); return md.digest(source); } catch (NoSuchAlgorithmException e) { e.printStackTrace(); } return null; } public static String toHex(byte buffer[]) { if(buffer == null) return null; System.out.println(">>> :"+Arrays.toString(buffer)); StringBuffer sb = new StringBuffer(buffer.length * 2); for(int i = 0;i<buffer.length ; i++) { sb.append(Character.forDigit((buffer[i] & 240)>>4, 16));//高位处理 sb.append(Character.forDigit(buffer[i] & 15, 16));//低位处理 } return sb.toString(); } public static long longFrom8Bytes(byte[] input,int offset,boolean littleEndian) { if(offset <0 || offset +8 > input.length) { throw new IllegalArgumentException("ssss"); } long value = 0; for(int count = 0;count<8;count++) { int shift=(littleEndian?count:(7-count))<<3; value |=((long)0xff<< shift) & ((long)input[offset+count] << shift); } return value; } public static long bytesToLong(byte[] input, int offset, boolean littleEndian) { if(offset <0 || offset+8>input.length) throw new IllegalArgumentException(String.format("less than 8 bytes from index %d is insufficient for long",offset)); ByteBuffer buffer = ByteBuffer.wrap(input,offset,8); if(littleEndian){ // ByteBuffer.order(ByteOrder) 方法指定字节序,即大小端模式(BIG_ENDIAN/LITTLE_ENDIAN) // ByteBuffer 默认为大端(BIG_ENDIAN)模式 buffer.order(ByteOrder.LITTLE_ENDIAN); } return buffer.getLong(); } public static void main(String[] args) throws IOException { String input="net.gdface.facelog.dborm.person.FlPersonBeanBase"; byte[] md5 = getMD5(input.getBytes()); System.out.printf("md5 [%s]\n",toHex(md5)); // 三种方式运算结果对比验证 DataInputStream dataInput = new DataInputStream(new ByteArrayInputStream(md5)); long l1 = dataInput.readLong(); long l2 = dataInput.readLong(); System.out.printf("l1=0x%x l2=0x%x,DataInputStream\n", l1,l2);
long ln1 = bytesToLong(md5,0, false); long ln2 = bytesToLong(md5,8, false); System.out.printf("ln1=0x%x ln2=0x%x,ByteBuffer\n", ln1,ln2);
long ll1 = longFrom8Bytes(md5,0, false); long ll2 = longFrom8Bytes(md5,8, false); System.out.printf("ll1=0x%x ll2=0x%x\n", ll1,ll2);
}
}
