package com.doumee.core.utils;

import java.io.File;
import java.io.FileInputStream;
import java.math.BigInteger;
import java.security.MessageDigest;
import java.util.HashMap;
import java.util.Map;

public class FileDigest {
	/**
	 * 计算文件的MD5值
	 * 
	 * @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 (Exception e) {
			e.printStackTrace();
			return null;
		}
		BigInteger bigInt = new BigInteger(1, digest.digest());
		return bigInt.toString(16);
	}

	/**
	 * 计算文件夹的MD5值
	 * 
	 * @param file
	 * @param listChild
	 * @return
	 */
	public static Map<String, String> getDirMD5(File file, boolean listChild) {
		if (!file.isDirectory()) {
			return null;
		}
		// <filepath,md5>
		Map<String, String> map = new HashMap<String, String>();
		String md5;
		File files[] = file.listFiles();
		for (int i = 0; i < files.length; i++) {
			File f = files[i];
			if (f.isDirectory() && listChild) {
				map.putAll(getDirMD5(f, listChild));
			} else {
				md5 = getFileMD5(f);
				if (md5 != null) {
					map.put(f.getPath(), md5);
				}
			}
		}
		return map;
	}

}