迭代HashMap，然后将整数写入文件

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

public class HashMapIteration {
    public static void main(String[] args) {
        // 创建一个HashMap并添加键值对
        Map<String, Integer> hashMap = new HashMap<>();
        hashMap.put("A", 1);
        hashMap.put("B", 2);
        hashMap.put("C", 3);

        // 迭代HashMap并将整数写入文件
        try {
            BufferedWriter writer = new BufferedWriter(new FileWriter("output.txt"));
            for (String key : hashMap.keySet()) {
                int value = hashMap.get(key);
                writer.write(String.valueOf(value));
                writer.newLine();
            }
            writer.close();
        } catch (IOException e) {
            e.printStackTrace();
        }
    }
}