采用Huffman编码进行文本文件压缩和解压缩，用Java代码实现

下面是用Java代码实现Huffman编码压缩和解压缩的示例：

import java.io.BufferedReader;
import java.io.DataOutputStream;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.InputStreamReader;
import java.util.HashMap;
import java.util.Map;
import java.util.PriorityQueue;

public class HuffmanCode {
    static Map<Character, String> huffmanCode = new HashMap<>();
    static StringBuilder stringBuilder = new StringBuilder();

    // 压缩文件
    public static void compressFile(String srcFile, String dstFile) throws Exception {
        FileInputStream fileInputStream = new FileInputStream(srcFile);
        BufferedReader bufferedReader = new BufferedReader(new InputStreamReader(fileInputStream));

        // 读入文件内容
        StringBuilder sb = new StringBuilder();
        while (bufferedReader.ready()) {
            sb.append(bufferedReader.readLine());
        }
        bufferedReader.close();
        fileInputStream.close();
        String content = sb.toString();

        // 生成Huffman树，并得到Huffman编码
        generateHuffmanTree(content);

        // 将文件内容转换为Huffman编码
        String huffmanCodeContent = toHuffmanCodeContent(content);

        // 写入压缩文件
        FileOutputStream fileOutputStream = new FileOutputStream(dstFile);
        DataOutputStream dataOutputStream = new DataOutputStream(fileOutputStream);
        for (int i = 0; i < huffmanCodeContent.length(); i += 8) {
            int x = Integer.parseInt(huffmanCodeContent.substring(i, i + 8), 2);
            dataOutputStream.writeByte(x);
        }
        dataOutputStream.close();
        fileOutputStream.close();
    }

    // 解压缩文件
    public static void decompressFile(String srcFile, String dstFile) throws Exception {
        FileInputStream fileInputStream = new FileInputStream(srcFile);
        BufferedReader bufferedReader = new BufferedReader(new InputStreamReader(fileInputStream));

        // 读入文件内容
        StringBuilder sb = new StringBuilder();
        while (bufferedReader.ready()) {
            int x = bufferedReader.read();
            String str = Integer.toBinaryString(x);
            while (str.length() < 8) {
                str = "0" + str;
            }
            sb.append(str);
        }
        bufferedReader.close();
        fileInputStream.close();
        String huffmanCodeContent = sb.toString();

        // 将