Java计算获取文件MD5

public staticString getFileMD5(File file){

if(!file.isFile()) {

return null;

}

MessageDigest digest;

FileInputStream fis;

byte[] buffer =new byte[1024];

try{

if(!file.isFile()) {

return"";

}

digest = MessageDigest.getInstance("MD5");

fis =newFileInputStream(file);

while(true) {

intlen;

if((len = fis.read(buffer,0,1024)) == -1) {

fis.close();

break;

}

digest.update(buffer,0, len);

}

}catch(Exception e) {

e.printStackTrace();

return null;

}

BigInteger var5 =newBigInteger(1, digest.digest());

returnString.format("%1$032x", var5);

}