【无标题】MD5大苏打撒

import java.io.File;
import java.io.FileInputStream;
import java.math.BigInteger;
import java.security.MessageDigest;
import java.security.NoSuchAlgorithmException;


public class MD5Util {
	private static final int BUFFER_SIZE = 8*1024;
	/**
	 * 获取单个文件的MD5值!
	 * 
	 * @param file
	 * @return
	 */

	public static String getFileMD5(File file) {
		if (!file.isFile()) {
			return "";
		}
		MessageDigest digest = null;
		FileInputStream in = null;
		byte buffer[] = new byte[BUFFER_SIZE];
		int len;
		try {
			digest = MessageDigest.getInstance("MD5");
			in = new FileInputStream(file);
			while ((len = in.read(buffer, 0, BUFFER_SIZE)) != -1) {
				digest.update(buffer, 0, len);
			}
			in.close();
		} catch (Exception e) {
			e.printStackTrace();
			return null;
		}
		BigInteger bigInt = new BigInteger(1, digest.digest());
		String beforeAdd0 = bigInt.toString(16);
		int _0toLeft = 32 - beforeAdd0.length();
		StringBuffer afterAdd0 = new StringBuffer();

		// 有个坑就是生成的md5可能不足32位...所以我需要去补齐他
		if (_0toLeft > 0) {
			for (int i = 0; i < _0toLeft; i++) {
				afterAdd0.append("0");
			}
		}
		afterAdd0.append(beforeAdd0);
		return afterAdd0.toString();
	}
	
	public static String getStringMD5(byte[] data) {
		
		MessageDigest digest = null;
		try {
			digest = MessageDigest.getInstance("MD5");
		} catch (NoSuchAlgorithmException e) {
			e.printStackTrace();
		}
		
		if(digest!=null)
		{
			digest.update(data);
			BigInteger bigInt = new BigInteger(1, digest.digest());
			String beforeAdd0 = bigInt.toString(16);
			int _0toLeft = 32 - beforeAdd0.length();
			StringBuffer afterAdd0 = new StringBuffer();
			
			// 有个坑就是生成的md5可能不足32位...所以我需要去补齐他
			if (_0toLeft > 0) {
				for (int i = 0; i < _0toLeft; i++) {
					afterAdd0.append("0");
				}
			}
			afterAdd0.append(beforeAdd0);
			return afterAdd0.toString();
		}
		else
		{
			return null;
		}
	}
	public static String getStringMD5(String text) {
	
		MessageDigest digest = null;
		try {
			digest = MessageDigest.getInstance("MD5");
		} catch (NoSuchAlgorithmException e) {
			e.printStackTrace();
		}
		
		if(digest!=null)
		{
			digest.update(text.getBytes());
			BigInteger bigInt = new BigInteger(1, digest.digest());
			String beforeAdd0 = bigInt.toString(16);
			int _0toLeft = 32 - beforeAdd0.length();
			StringBuffer afterAdd0 = new StringBuffer();
			
			// 有个坑就是生成的md5可能不足32位...所以我需要去补齐他
			if (_0toLeft > 0) {
				for (int i = 0; i < _0toLeft; i++) {
					afterAdd0.append("0");
				}
			}
			afterAdd0.append(beforeAdd0);
			return afterAdd0.toString();
		}
		else
		{
			return null;
		}
	}
	
	
}