圖片上傳的時候，通過對比兩張圖片的MD5值，判斷圖片是否上傳成功。

package com.kedacom.testdemo.javaTest;

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

/**
 * @Dec ：
 * @Author : Caowj
 * @Date : 2018/8/1 8:58
 */
 

public class Test1 {
    /**
     * 獲取單個檔案的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());
        String md5 = bigInt.toString(16);
        System.out.println("filePath：" + file.getPath() + "\nmd5：" + md5);
        return md5;
    }

    /**
     * 獲取資料夾中檔案的MD5值
     *
     * @param file
     * @param listChild ;true遞迴子目錄中的檔案
     * @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;
    }

    public static void main(String[] args) {

//        http://122.138.250.132:9900/file/ydzf/16/16000031/b64_MTYwMDAwMzFfMQ.jpg//問題圖片

//        String image1 = "C:\\Users\\kd\\Desktop\\b64_MTYwMDAwMzFfMQ.jpg.png";
//        String image2 = "C:\\Users\\kd\\Desktop\\16000031_1.jpg";

        String image1 = "C:\\Users\\kd\\Desktop\\b64_MTYwMDAwMzFfMg.jpg";
        String image2 = "C:\\Users\\kd\\Desktop\\16000031_2.jpg";

        File file1 = new File(image1);
        File file2 = new File(image2);
        System.out.println(getFileMD5(file1).equals(getFileMD5(file2)));

        String s = file1.getPath();
        System.out.println(s);
    }
}

日誌輸出：

filePath：C:\Users\kd\Desktop\zhcx\b64_MTYwMDAwMzFfMg.jpg
md5：576b742dae427ab95478513744c368ad

filePath：C:\Users\kd\Desktop\zhcx\16000031_2.jpg
md5：576b742dae427ab95478513744c368ad
true

C:\Users\kd\Desktop\zhcx\b64_MTYwMDAwMzFfMg.jpg