java - 如何按键对Java中的 map 进行排序，但如果键是(字符串+数字)的组合

Question

我创建了一个名为 result 的 map 。

在 sortByKeys 方法中，由于我的键是带有数字值的字符串，我已将它们转换为整数键类型 Map，然后对它们进行排序。

Map<String, String> unsortMap = new TreeMap<String, String>();
unsortMap.put("room~1", "e");
unsortMap.put("room~2", "y");
unsortMap.put("room~10", "n");
unsortMap.put("room~4", "j");
unsortMap.put("room~5", "m");
unsortMap.put("room~3", "f");

Set set2 = unsortMap.entrySet();
Iterator iterator2 = set2.iterator();

while (iterator2.hasNext()) {
     /* Iterate */
    Map.Entry me2 = (Map.Entry) iterator2.next();
    String key = (String) me2.getKey();
    Object value = (Object) me2.getValue();
    System.out.println("Key ==>" + key + " Value ==>" + value);
}

# Current Output:#
/* current result */
Key ==>room~1 Value ==>e 
Key ==>room~10 Value ==>n
Key ==>room~2 Value ==>y
Key ==>room~3 Value ==>f
Key ==>room~4 Value ==>j
Key ==>room~5 Value ==>m

#Expected O/p:#
/* required result */
Key ==>room~1 Value ==>e
Key ==>room~2 Value ==>y
Key ==>room~3 Value ==>f
Key ==>room~4 Value ==>j
Key ==>room~5 Value ==>m
Key ==>room~10 Value ==>n 

Answer 1

创建自定义键对象

public class Key implements Comparable<Key>{
    String name;
    int id;

    public Key(String name, int id) {
        this.name = name;
        this.id = id;
    }

    @Override
    public int compareTo(Key o) {
        if(Objects.equals(name, o.name)){
            return Integer.compare(id, o.id);
        }else{
            return name.compareTo(o.name);
        }
    }

    @Override
    public String toString() {
        return name +"~"+ id;
    }

    @Override
    public boolean equals(Object o){
    ...
    @Override
    public int hashCode(){
    ...
}

并像这样使用它:

    Map<Key, String> unsortMap = new TreeMap<>();
    unsortMap.put(new Key("room", 5), "e");

但是如果字符串总是有空间，你应该在键中使用它