132 lines
3.9 KiB
Java
132 lines
3.9 KiB
Java
import java.nio.charset.StandardCharsets;
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import java.security.MessageDigest;
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import java.security.NoSuchAlgorithmException;
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import java.util.ArrayList;
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import java.util.List;
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class MerkleNode {
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private String hash;
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private MerkleNode left;
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private MerkleNode right;
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public MerkleNode(String hash) {
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this.hash = hash;
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this.left = null;
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this.right = null;
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}
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public String getHash() {
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return hash;
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}
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public MerkleNode getLeft() {
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return left;
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}
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public void setLeft(MerkleNode left) {
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this.left = left;
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}
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public MerkleNode getRight() {
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return right;
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}
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public void setRight(MerkleNode right) {
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this.right = right;
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}
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}
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public class MerkleTree {
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private MerkleNode root;
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public MerkleTree(List<String> data) {
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this.root = buildTree(data);
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}
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public MerkleNode getRoot() {
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return root;
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}
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private MerkleNode buildTree(List<String> data) {
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List<MerkleNode> nodes = new ArrayList<>();
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for (String value : data) {
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String hash = calculateHash(value);
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nodes.add(new MerkleNode(hash));
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}
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while (nodes.size() > 1) {
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List<MerkleNode> tempNodes = new ArrayList<>();
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for (int i = 0; i < nodes.size(); i += 2) {
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MerkleNode left = nodes.get(i);
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MerkleNode right = (i + 1 < nodes.size()) ? nodes.get(i + 1) : null;
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String concatHash = left.getHash() + ((right != null) ? right.getHash() : "");
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String parentHash = calculateHash(concatHash);
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MerkleNode parent = new MerkleNode(parentHash);
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parent.setLeft(left);
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parent.setRight(right);
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tempNodes.add(parent);
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}
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nodes = tempNodes;
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}
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return nodes.get(0);
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}
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private String calculateHash(String data) {
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try {
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MessageDigest digest = MessageDigest.getInstance("SHA-256");
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byte[] hash = digest.digest(data.getBytes(StandardCharsets.UTF_8));
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StringBuilder hexString = new StringBuilder();
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for (byte b : hash) {
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String hex = Integer.toHexString(0xff & b);
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if (hex.length() == 1) {
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hexString.append('0');
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}
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hexString.append(hex);
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}
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return hexString.toString();
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} catch (NoSuchAlgorithmException e) {
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e.printStackTrace();
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}
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return null;
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}
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public static void main(String[] args) {
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List<String> data = new ArrayList<>();
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data.add("Comment 1");
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data.add("Comment 2");
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data.add("Comment 3");
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data.add("Comment 4");
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data.add("Private Key");
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data.add("Like Count");
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MerkleTree merkleTree = new MerkleTree(data);
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MerkleNode root = merkleTree.getRoot();
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printMerkleTree(root, 0);
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}
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private static void printMerkleTree(MerkleNode root, int level) {
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if (root == null) {
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return;
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}
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for (int i = 0; i < level; i++) {
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System.out.print(" ");
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}
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System.out.println("|-- " + root.getHash());
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printMerkleTree(root.getLeft(), level + 1);
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printMerkleTree(root.getRight(), level + 1);
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}
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}
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/*这个程序定义了一个MerkleNode类表示梅克尔树中的节点，并提供了用于获取哈希值和子节点的方法。MerkleTree类构建了梅克尔树，并提供了获取根节点的方法。程序中的calculateHash方法使用SHA-256算法计算数据的哈希值。
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在main方法中，创建一个包含评论索引、评论哈希、私钥签名和点赞数的数据列表，并使用该数据构建一个梅克尔树。然后，打印出整个梅克尔树的结构。*/ |