安卓获取文件MD5值
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参考技术A public static String getFileMD5(File file)if (!file.isFile())
return null;
MessageDigest digest = null;
FileInputStream in = null;
byte buffer[] = new byte[1024];
int len;
try
digest = MessageDigest.getInstance("MD5");
in = new FileInputStream(file);
while ((len = in.read(buffer, 0, 1024)) != -1)
digest.update(buffer, 0, len);
in.close();
catch (Exception e)
e.printStackTrace();
return null;
BigInteger bigInt = new BigInteger(1, digest.digest());
return bigInt.toString(16);
如何用vba获取文件的MD5 Hash值?
MD5 可以作为文件的指纹。
MD5就可以为任何文件(不管其大小、格式、数量)产生一个同样独一无二的“数字指纹”,如果任何人对文件做了任何改动,其MD5值也就是对应的“数字指纹”都会发生变化。
如果要获取任意文件的MD5值,可以使用这些API函数直接获取MD5Init ,MD5Update,MD5Final 。
可以使用如下的代码:
Option Base 0 Public Type MD5_CTX i(1) As Long buf(3) As Long inc(63) As Byte digest(15) As Byte End Type Public Declare Sub MD5Init Lib "Cryptdll.dll" (ByVal pContex As Long) Public Declare Sub MD5Final Lib "Cryptdll.dll" (ByVal pContex As Long) Public Declare Sub MD5Update Lib "Cryptdll.dll" (ByVal pContex As Long, ByVal lPtr As Long, ByVal nSize As Long) Public Function ConvBytesToBinaryString(bytesIn() As Byte) As String Dim i As Long Dim nSize As Long Dim strRet As String nSize = UBound(bytesIn) For i = 0 To nSize strRet = strRet & Right$("0" & Hex(bytesIn(i)), 2) Next ConvBytesToBinaryString = strRet End Function Public Function GetMD5Hash(bytesIn() As Byte) As Byte() Dim ctx As MD5_CTX Dim nSize As Long nSize = UBound(bytesIn) + 1 MD5Init VarPtr(ctx) MD5Update ByVal VarPtr(ctx), ByVal VarPtr(bytesIn(0)), nSize MD5Final VarPtr(ctx) GetMD5Hash = ctx.digest End Function Public Function GetMD5Hash_Bytes(bytesIn() As Byte) As String GetMD5Hash_Bytes = ConvBytesToBinaryString(GetMD5Hash(bytesIn)) End Function Public Function GetMD5Hash_String(ByVal strIn As String) As String GetMD5Hash_String = GetMD5Hash_Bytes(StrConv(strIn, vbFromUnicode)) End Function Public Function GetMD5Hash_File(ByVal strFile As String) As String Dim lFile As Long Dim bytes() As Byte Dim lSize As Long lSize = FileLen(strFile) If (lSize) Then lFile = FreeFile ReDim bytes(lSize - 1) Open strFile For Binary As lFile Get lFile, , bytes Close lFile GetMD5Hash_File = GetMD5Hash_Bytes(bytes) End If End Function
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