区块链的原理与应用? -2

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@AllArgsConstructorpublic 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.JSON ;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{@  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);    }}