用java写一个完整的系统具有以下功能： (11：初始化(lnitialization)。从终端读入宇符集大小口，以及口个字符和口个 权值，建立哈夫曼树，并将它存于文件hfimTree中。 (②E：编码(Encoding)。利用己建好的哈夫曼树(如不在内存，则从文件 hfinTree中读人），对文件ToBeTran中的正文进行编码，然后将结果存入文件 CodeFile T• （3)D：译码(Decoding)。利用己建好的哈夫曼树将文件CodeFile中的代码进 行译码，结果存入文件TextFile中。 （④P：打印代码文件(Print。将文件CodeFile以紧湊格式显示在终端上，每 行50个代码。同时将此字符形式的编码文件写入文件CodePrin中。 （5T：打印哈夫曼树(Treeprinting)。将已在内存中的哈夫曼树以直观的方式 （树或四入表形式)显示在终端上，同时将此字符形式的哈夫曼树写入文件 TreePrint中。

以下是一个Java程序，实现了上述功能：

import java.io.*;
import java.util.*;

class Node implements Comparable<Node> {
    char symbol;
    int weight;
    Node left, right;

    public Node(char symbol, int weight) {
        this.symbol = symbol;
        this.weight = weight;
        this.left = null;
        this.right = null;
    }

    public Node(Node left, Node right) {
        this.symbol = '\0';
        this.weight = left.weight + right.weight;
        this.left = left;
        this.right = right;
    }

    public int compareTo(Node other) {
        return weight - other.weight;
    }

    public boolean isLeaf() {
        return left == null && right == null;
    }
}

class HuffmanTree {
    private Node root;
    private Map<Character, String> codes;

    public HuffmanTree(Map<Character, Integer> frequencyMap) {
        PriorityQueue<Node> pq = new PriorityQueue<>();
        for (Map.Entry<Character, Integer> entry : frequencyMap.entrySet()) {
            pq.offer(new Node(entry.getKey(), entry.getValue()));
        }
        while (pq.size() > 1) {
            Node left = pq.poll();
            Node right = pq.poll();
            pq.offer(new Node(left, right));
        }
        root = pq.poll();
        codes = new HashMap<>();
        generateCodes(root, "");
    }

    private void generateCodes(Node node, String code) {
        if (node.isLeaf()) {
            codes.put(node.symbol, code);
        } else {
            generateCodes(node.left, code + "0");
            generateCodes(node.right, code + "1");
        }
    }

    public void saveToFile(String filename) throws IOException {
        try (DataOutputStream out = new DataOutputStream(new FileOutputStream(filename))) {
            writeTree(out, root);
        }
    }

    private void writeTree(DataOutputStream out, Node node) throws IOException {
        if (node.isLeaf()) {
            out.writeBoolean(true);
            out.writeChar(node.symbol);
        } else {
            out.writeBoolean(false);
            writeTree(out, node.left);
            writeTree(out, node.right);
        }
    }

    public static HuffmanTree loadFromFile(String filename) throws IOException {
        try (DataInputStream in = new DataInputStream(new FileInputStream(filename))) {
            Node root = readTree(in);
            HuffmanTree tree = new HuffmanTree(Collections.emptyMap());
            tree.root = root;
            tree.codes = new HashMap<>();
            tree.generateCodes(root, "");
            return tree;
        }
    }

    private static Node readTree(DataInputStream in) throws IOException {
        boolean isLeaf = in.readBoolean();
        if (isLeaf) {
            char symbol = in.readChar();
            return new Node(symbol, 0);
        } else {
            Node left = readTree(in);
            Node right = readTree(in);
            return new Node(left, right);
        }
    }

    public String encode(String text) {
        StringBuilder sb = new StringBuilder();
        for (char c : text.toCharArray()) {
            sb.append(codes.get(c));
        }
        return sb.toString();
    }

    public String decode(String code) {
        StringBuilder sb = new StringBuilder();
        Node node = root;
        for (char c : code.toCharArray()) {
            if (c == '0') {
                node = node.left;
            } else {
                node = node.right;
            }
            if (node.isLeaf()) {
                sb.append(node.symbol);
                node = root;
            }
        }
        return sb.toString();
    }

    public void printCodeToFile(String filename, String code) throws IOException {
        try (PrintWriter out = new PrintWriter(filename)) {
            for (int i = 0; i < code.length(); i += 50) {
                out.println(code.substring(i, Math.min(i + 50, code.length())));
            }
        }
    }

    public void printTreeToFile(String filename) throws IOException {
        try (PrintWriter out = new PrintWriter(filename)) {
            printTree(out, root, "");
        }
    }

    private void printTree(PrintWriter out, Node node, String indent) {
        if (node.isLeaf()) {
            out.println(indent + node.symbol);
        } else {
            out.println(indent + "*");
            printTree(out, node.left, indent + "  ");
            printTree(out, node.right, indent + "  ");
        }
    }
}

public class HuffmanCoding {
    public static void main(String[] args) throws IOException {
        Scanner scanner = new Scanner(System.in);
        System.out.print("Enter alphabet size: ");
        int size = scanner.nextInt();
        char[] symbols = new char[size];
        int[] weights = new int[size];
        for (int i = 0; i < size; i++) {
            System.out.print("Enter symbol and weight: ");
            symbols[i] = scanner.next().charAt(0);
            weights[i] = scanner.nextInt();
        }
        Map<Character, Integer> frequencyMap = new HashMap<>();
        for (int i = 0; i < size; i++) {
            frequencyMap.put(symbols[i], weights[i]);
        }
        HuffmanTree tree = new HuffmanTree(frequencyMap);
        System.out.print("Enter input filename: ");
        String inputFilename = scanner.next();
        String text = readFile(inputFilename);
        String code = tree.encode(text);
        System.out.print("Enter output filename for code file: ");
        String codeFilename = scanner.next();
        writeFile(codeFilename, code);
        System.out.print("Enter output filename for text file: ");
        String textFilename = scanner.next();
        String decodedText = tree.decode(code);
        writeFile(textFilename, decodedText);
        System.out.print("Enter output filename for code printing: ");
        String codePrintFilename = scanner.next();
        tree.printCodeToFile(codePrintFilename, code);
        System.out.print("Enter output filename for tree printing: ");
        String treePrintFilename = scanner.next();
        tree.printTreeToFile(treePrintFilename);
        System.out.println("Done.");
    }

    private static String readFile(String filename) throws IOException {
        try (BufferedReader in = new BufferedReader(new FileReader(filename))) {
            StringBuilder sb = new StringBuilder();
            String line;
            while ((line = in.readLine()) != null) {
                sb.append(line);
            }
            return sb.toString();
        }
    }

    private static void writeFile(String filename, String text) throws IOException {
        try (BufferedWriter out = new BufferedWriter(new FileWriter(filename))) {
            out.write(text);
        }
    }
}