CreateMd5.java

package com.zhangzhihao.FileUpload.Java.Utils;

import org.jetbrains.annotations.NotNull;
import org.springframework.web.multipart.MultipartFile;

import java.io.InputStream;
import java.security.MessageDigest;


public class CreateMd5 {
    public static StringBuilder createMd5(@NotNull final MultipartFile file)
            throws Exception {
        StringBuilder sb = new StringBuilder();
        //生成MD5实例
        MessageDigest md5 = MessageDigest.getInstance("MD5");
        InputStream inputStream = file.getInputStream();
        int available = inputStream.available();
        byte[] bytes = new byte[available];
        md5.update(bytes);
        for (byte by : md5.digest()) {
            //将生成的字节MD5值转换成字符串
            sb.append(String.format("%02X", by));
        }
        return sb;
    }
}