web后台解析apk获取信息

• 在后台时要根据上传的apk自动提取里面的版本号等信息，这时可以利用下面这个开源库快速实现：
  hsiafan/apk-parser: Apk parser for java
  https://github.com/hsiafan/apk-parser

• 同时提供一个经过测试可用的获取MD5的工具类

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

import org.apache.commons.codec.binary.Hex;
import org.apache.commons.codec.digest.DigestUtils;
import org.springframework.web.multipart.MultipartFile;

/**
 * 此工具类依赖commons-codec
 * //https://mvnrepository.com/artifact/commons-codec/commons-codec/1.11
 * compile ('commons-codec:commons-codec:1.11')
 */

public class Md5CaculateUtil {

    /**
     * 获取一个文件的md5值(可处理大文件)
     *
     * @return md5 value
     */
    public static String getMD5(File file) {
        FileInputStream fileInputStream = null;
        try {
            MessageDigest MD5 = MessageDigest.getInstance("MD5");
            fileInputStream = new FileInputStream(file);
            byte[] buffer = new byte[8192];
            int length;
            while ((length = fileInputStream.read(buffer)) != -1) {
                MD5.update(buffer, 0, length);
            }
            return new String(Hex.encodeHex(MD5.digest()));
        } catch (Exception e) {
            e.printStackTrace();
            return null;
        } finally {
            try {
                if (fileInputStream != null) {
                    fileInputStream.close();
                }
            } catch (IOException e) {
                e.printStackTrace();
            }
        }
    }

    /**
     * 获取上传文件的md5
     *
     * @param file
     * @return
     * @throws IOException
     */
    public static String getMD5(MultipartFile file) {

        try {
            byte[] uploadBytes = file.getBytes();
            MessageDigest md5 = MessageDigest.getInstance("MD5");
            byte[] digest = md5.digest(uploadBytes);
            String hashString = new BigInteger(1, digest).toString(16);
            return hashString;
        } catch (Exception e) {
            e.printStackTrace();
        }
        return null;

    }

    /**
     * 求一个字符串的md5值
     *
     * @param target 字符串
     * @return md5 value
     */
    public static String MD5(String target) {
        return DigestUtils.md5Hex(target);
    }

    public static void main(String[] args) {
        long beginTime = System.currentTimeMillis();
        File file = new File("D:/1/pdi-ce-7.0.0.0-24.zip");
        String md5 = getMD5(file);
        long endTime = System.currentTimeMillis();
        System.out.println("MD5:" + md5 + "\n 耗时:" + ((endTime - beginTime) / 1000) + "s");
    }
}