数据类型map的排序
1. 根据键排序
TreeMap<K, V> 是JDK内置包(java.util)可实现的排序map,在构造函数中传入比较规则TreeMap(Comparator<? super K> comparator)
①重写比较器类,定制排序规则
class MapKeyComparator implements Comparator<String>{
@Override
public int compare(String o1, String o2) {
return o2.compareTo(o1);
}
}
②建立TreeMap对象时,传入比较规则
Map<String, Integer> sortMap = new TreeMap<String, Integer>(
new MapKeyComparator()