java中类似php md5的算法，可以取得文件，字符串和输入流的md5值

import java.io.BufferedInputStream;
import java.io.ByteArrayInputStream;
import java.io.FileInputStream;
import java.io.InputStream;
import java.security.MessageDigest;

public class MD5Utils
{
private static MD5Utils instance=null;
private static MessageDigest md5 =null;
private MD5Utils(){};
public static MD5Utils getInstance()
{
try
{
instance=new MD5Utils();
md5=MessageDigest.getInstance("MD5");
}catch(Exception e)
{
return null;
}
return instance;
}
public String getStringHash(String source)
{
String hash=null;
try
{
ByteArrayInputStream in=new ByteArrayInputStream(source.getBytes());
hash=getStreamHash(in);
in.close();
}catch (Exception e)
{
e.printStackTrace();
}
return hash;
}
public String getFileHash(String file)
{
String hash=null;
try
{
FileInputStream in=new FileInputStream(file);
hash=getStreamHash(in);
in.close();
}catch (Exception e)
{
e.printStackTrace();
}
return hash;
}
public String getStreamHash(InputStream stream)
{
String hash=null;
byte[] buffer = new byte[1024];
BufferedInputStream in=null;
try
{
in=new BufferedInputStream(stream);
int numRead = 0;
while ((numRead = in.read(buffer)) > 0)
{
md5.update(buffer, 0, numRead);
}
in.close();
hash=toHexString(md5.digest());
}catch (Exception e)
{
if(in!=null)try{in.close();}catch (Exception ex) {ex.printStackTrace();}
e.printStackTrace();
}
return hash;
}
private String toHexString(byte[] b) {
StringBuilder sb = new StringBuilder(b.length * 2);
for (int i = 0; i < b.length; i++) {
sb.append(hexChar[(b[i] & 0xf0) >>> 4]);
sb.append(hexChar[b[i] & 0x0f]);
}
return sb.toString();
}
private char[] hexChar = {'0', '1', '2', '3',
'4', '5', '6', '7',
'8', '9', 'a', 'b',
'c', 'd', 'e', 'f'};

public static void main(String[] args)
{
System.out.println(MD5Utils.getInstance().getStringHash("yepanpan"));
//System.out.println(MD5Utils.getInstance().getFileHash("E://software//2003_Visio_Pro.iso"));
}
}