区块链的原理与应用? -2

  1. 云栖社区>
  2. 博客>
  3. 正文

区块链的原理与应用? -2

ykmimi.com 2019-07-02 11:33:45 浏览146
展开阅读全文

接着上一篇.
上一篇还没有输出,其实加入了index在实体类中.

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.
    }
}

测试类:

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 {

    //声明一个区块链,用于添加Block实体
    public static ArrayList<Block> blockChain = new ArrayList<>();

    public static void main(String[] args) {
        //test1 测试三个被加密字符串 加密后的hash值的差别
        /**
         * 虽然第三条信息仅仅多一个".",但加密后的数据hash相差极大
         */
//        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 创建区块链逻辑, 因为第一个块没有上一个块的hash头部值,所以输入0 作为前一个块的previous hash
//        /**
//         * 由于在{@link SHA256Util#calculateHash(Block)}
//         * 中对同时产生的new Date().getTime() (timestamp)
//         * 也加入进行了hash加密,所以固有的message (data)及
//         * previoushash之和进行了加密.
//         */
//        Block genesisBlock = new Block(0,"这是第一个区块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,"这是第二个区块,以及其中信息!!!它的前区块头部hash我们拿上一个的来使用",hash1);
//        String hash2 = secondBlock.getHash(); //
//        System.out.println("Hash for block 2 : "+hash2);
//
//        Block thirdBlock = new Block(2,"这是第三个区块,它的hash应该已经被前两个的信息纳入进来了,它的hash如果对不上,那么说明前面的信息被改动过了",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,"区块链上第一小节","0"));
//        blockChain.add(new Block(1,"区块链第二小节",blockChain.get(blockChain.size()-1).getHash()));
//        blockChain.add(new Block(2,"区块链第三小节",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, "创世块", "0"));
            }
            index++;
            blockChain.add(new Block(index, "区块内容" + 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);
    }


    //模拟一些交易信息
    private static String blockChainMessage(int getNumber) {
        Random random = new Random(getNumber);
        long l = random.nextLong();
        System.out.println("blockChainMessage:" + l);
        return String.valueOf(l);
    }
}

网友评论

登录后评论
0/500
评论
ykmimi.com
+ 关注