區塊鏈的原理與應用? -2

接着上一篇.
上一篇還沒有輸出,其實加入了index在實體類中.

package com.sha256.sha256.bean;

import com.sha256.sha256.utils.SHA256Util;
import lombok.AllArgsConstructor;
import lombok.Data;
import lombok.NoArgsConstructor;

import java.util.Date;

@Data
@NoArgsConstructor
@AllArgsConstructor
public class Block {

    private long index;
    private String hash; // our signature
    private String previousHash; // the hash of previous block
    private String data; //our data will be a simple message.
    private long timeStamp; //as number of milliseconds since 1/1/1970.

    //Block Constructor
    public Block(long index,String data,String previousHash){
        this.index = index;
        this.data = data;
        this.previousHash = previousHash;
        this.timeStamp = new Date().getTime();
        this.hash = SHA256Util.calculateHash(this); //Making sure we do this after we set the other values.
    }
}

測試類:

package com.sha256.sha256.test;

import com.alibaba.fastjson.JSONArray;
import com.alibaba.fastjson.JSONObject;
import com.google.gson.GsonBuilder;
import com.sha256.sha256.bean.Block;
import com.sha256.sha256.utils.SHA256Util;

import java.util.ArrayList;
import java.util.Random;

public class TestSHA256 {

    //聲明一個區塊鏈,用於添加Block實體
    public static ArrayList<Block> blockChain = new ArrayList<>();

    public static void main(String[] args) {
        //test1 測試三個被加密字符串 加密後的hash值的差別
        /**
         * 雖然第三條信息僅僅多一個".",但加密後的數據hash相差極大
         */
//        String message0 = "我是要被加密的信息";
//        String message1 = "我是要被加密的信息";
//        String message2 = "我是要被加密的信息.";
//        String encryptionMessage0 = SHA256Util.applySha256(message0);
//        String encryptionMessage1 = SHA256Util.applySha256(message1);
//        String encryptionMessage2 = SHA256Util.applySha256(message2);
//        System.out.println(encryptionMessage0);
//        System.out.println(encryptionMessage1);
//        System.out.println(encryptionMessage2);
//
//        //test2 創建區塊鏈邏輯, 因爲第一個塊沒有上一個塊的hash頭部值,所以輸入0 作爲前一個塊的previous hash
//        /**
//         * 由於在{@link SHA256Util#calculateHash(Block)}
//         * 中對同時產生的new Date().getTime() (timestamp)
//         * 也加入進行了hash加密,所以固有的message (data)及
//         * previoushash之和進行了加密.
//         */
//        Block genesisBlock = new Block(0,"這是第一個區塊中的要被加密的信息和交易信息","0");
//        String hash1 = genesisBlock.getHash();
//        System.out.println("Hash for block 1 : "+hash1);
//
//        Block secondBlock = new Block(1,"這是第二個區塊,以及其中信息!!!它的前區塊頭部hash我們拿上一個的來使用",hash1);
//        String hash2 = secondBlock.getHash(); //
//        System.out.println("Hash for block 2 : "+hash2);
//
//        Block thirdBlock = new Block(2,"這是第三個區塊,它的hash應該已經被前兩個的信息納入進來了,它的hash如果對不上,那麼說明前面的信息被改動過了",hash2);
//        String hash3 = thirdBlock.getHash();
//        System.out.println("Hash for block 3 : "+hash3);
//
////        test3 add our blocks to the blockchain ArrayList :
//        blockChain.add(new Block(0,"區塊鏈上第一小節","0"));
//        blockChain.add(new Block(1,"區塊鏈第二小節",blockChain.get(blockChain.size()-1).getHash()));
//        blockChain.add(new Block(2,"區塊鏈第三小節",blockChain.get(blockChain.size()-1).getHash()));
        int chainNumber = 24;
        int index = 0;
        while (chainNumber > 0) {
            System.out.println("blockChain.size():" + blockChain.size());
            if (blockChain.size() == 0) {
                blockChain.add(new Block(0, "創世塊", "0"));
            }
            index++;
            blockChain.add(new Block(index, "區塊內容" + blockChainMessage(index), blockChain.get(blockChain.size() - 1).getHash()));
            chainNumber--;
        }

//        JSONArray blockChainJson1 = (JSONArray)JSONArray.toJSON(blockChain); //JSONArray是不排版的
//        System.out.println(blockChainJson1);
        String blockChainJson = new GsonBuilder().setPrettyPrinting().create().toJson(blockChain);

        System.out.println(blockChainJson);
    }


    //模擬一些交易信息
    private static String blockChainMessage(int getNumber) {
        Random random = new Random(getNumber);
        long l = random.nextLong();
        System.out.println("blockChainMessage:" + l);
        return String.valueOf(l);
    }
}