题解 | #配置文件恢复#

使用stream过滤map

import java.util.HashMap;
import java.util.List;
import java.util.Map;
import java.util.Scanner;
import java.util.stream.Collectors;

// 注意类名必须为 Main, 不要有任何 package xxx 信息
public class Main {
    static Map<String, String> map = new HashMap<String, String>() {{
        put("reset", "reset what");
        put("reset board", "board fault");
        put("board add", "where to add");
        put("board delete", "no board at all");
        put("reboot backplane", "impossible");
        put("backplane abort", "install first");
    }};

    public static void main(String[] args) {
        Scanner in = new Scanner(System.in);
        // 注意 hasNext 和 hasNextLine 的区别
        while (in.hasNextLine()) { // 注意 while 处理多个 case
            System.out.println(cmd(in.nextLine()));
        }
    }

    private static String cmd(String str) {
        String[] words = str.split(" ");
        List<Map.Entry<String, String>> list = map.entrySet().stream().filter(entry -> {
            String[] keywords = entry.getKey().split(" ");
            if (words.length != keywords.length) {
                return false;
            }
            for (int i = 0; i < keywords.length; i++) {
                if (!keywords[i].startsWith(words[i])) {
                    return false;
                }
            }
            return true;
        }).collect(Collectors.toList());
        return list.size() == 1 ? list.get(0).getValue() : "unknown command";
    }
}