sha256

落日映苍穹つ 2022-07-03 23:39 219阅读 0赞

import java.io.File;
    import java.io.FileInputStream;
    import java.math.BigInteger;
    import java.security.MessageDigest;
    
    public class SHA256File {
    
    	String official_checksum = "";
    
    	void OnEncFile() {
    
    		System.out.println("Getting file...");
    
    		File file = new File("/datas/upload/zip/bankcode_NJCBCNBN123444_20170328095225.zip");
    
    		if (file.exists()) {
    
    			System.out.println("File got.");
    
    		} else {
    
    			System.err.println("File not got.");
    
    		}
    
    		System.out.print("Calcuclating SHA-256 checksum......");
    
    		String FileSHA256 = getFileSHA256(file);
    
    		System.out.println();
    
    		System.out.println("File's SHA-256 checksum is: ");
    
    		System.out.println(FileSHA256);
    
    		System.out.println(official_checksum + " --- the official checksum");
    
    		if (official_checksum.equals(FileSHA256)) {
    
    			System.out.println("SHA-256 checksums are the same.");
    
    		} else {
    
    			System.err.println("SHA-256 checksums differ!!!!");
    
    		}
    
    	}
    
    	public  static String getFileSHA256(File file) {
    
    //		if (!file.isFile()) {
    //
    //			System.err.println("not file");
    //
    //			return null;
    //
    //		}
    
    		MessageDigest digest = null;
    
    		FileInputStream in = null;
    
    		byte buffer[] = new byte[1024];
    
    		int len;
    
    		try {
    
    			digest = MessageDigest.getInstance("SHA-256");
    
    			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);
    
    	}
    	
    	public static void main(String[] args) {
    		new SHA256File().OnEncFile();
    	}
    
    }