java 文件的md5值_java计算文件的MD5值

网上找的JAVA计算文件的MD5值的工具类，保存下做个记录。

package phreadpool;

import java.io.File;

import java.io.FileInputStream;

import java.io.FileNotFoundException;

import java.io.IOException;

import java.math.BigInteger;

import java.security.MessageDigest;

import java.security.NoSuchAlgorithmException;

import java.util.HashMap;

import java.util.Map;

public class FileMDFive {

public static void main(String[] args) {

System.out.println(FileMDFive.getFileMD5(new File("D:\\api.docx")));

}

/**

* 根据文件计算出文件的MD5

* @param file

* @return

*/

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 (NoSuchAlgorithmException e) {

e.printStackTrace();

} catch (FileNotFoundException e) {

e.printStackTrace();

} catch (IOException e) {

e.printStackTrace();

}

BigInteger bigInt = new BigInteger(1, digest.digest());

return bigInt.toString(16);

}

/**

* 获取文件夹中的文件的MD5值

* @param file

* @param listChild

* @return

*/

public static MapgetDirMD5(File file, boolean listChild){

if(! file.isDirectory()){

return null;

}

Mapmap = new HashMap();

String md5;

File[] files = file.listFiles();

for (int i = 0; i < files.length; i++) {

File file2 = files[i];

if(file2.isDirectory() && listChild){

map.putAll(getDirMD5(file2, listChild));

}else{

md5 = getFileMD5(file2);

if(md5 != null){

map.put(file2.getPath(), md5);

}

}

}

return map;

}

}