如何读取和写入文件的HashMap？

import java.io.BufferedReader;
import java.io.FileReader;
import java.io.IOException;
import java.util.HashMap;
import java.util.Map;

public class FileToHashMap {
    public static void main(String[] args) {
        String filePath = "path/to/your/file.txt";
        Map<String, String> hashMap = readFileToHashMap(filePath);
        System.out.println(hashMap);
    }

    public static Map<String, String> readFileToHashMap(String filePath) {
        Map<String, String> hashMap = new HashMap<>();
        try (BufferedReader br = new BufferedReader(new FileReader(filePath))) {
            String line;
            while ((line = br.readLine()) != null) {
                String[] keyValue = line.split(",");
                hashMap.put(keyValue[0], keyValue[1]);
            }
        } catch (IOException e) {
            e.printStackTrace();
        }
        return hashMap;
    }
}

import java.io.BufferedWriter;
import java.io.FileWriter;
import java.io.IOException;
import java.util.HashMap;
import java.util.Map;

public class HashMapToFile {
    public static void main(String[] args) {
        Map<String, String> hashMap = new HashMap<>();
        hashMap.put("key1", "value1");
        hashMap.put("key2", "value2");
        hashMap.put("key3", "value3");

        String filePath = "path/to/your/output.txt";
        writeHashMapToFile(hashMap, filePath);
    }

    public static void writeHashMapToFile(Map<String, String> hashMap, String filePath) {
        try (BufferedWriter bw = new BufferedWriter(new FileWriter(filePath))) {
            for (Map.Entry<String, String> entry : hashMap.entrySet()) {
                bw.write(entry.getKey() + "," + entry.getValue());
                bw.newLine();
            }
        } catch (IOException e) {
            e.printStackTrace();
        }
    }
}