带条件的嵌套HashMap上的流

import java.util.HashMap;
import java.util.Map;
import java.util.stream.Stream;

public class NestedHashMapStreamExample {
    public static void main(String[] args) {
        // 创建一个带有嵌套HashMap的示例数据
        Map<String, Map<String, Integer>> nestedHashMap = new HashMap<>();
        Map<String, Integer> innerHashMap1 = new HashMap<>();
        innerHashMap1.put("A", 1);
        innerHashMap1.put("B", 2);
        nestedHashMap.put("Key1", innerHashMap1);
        Map<String, Integer> innerHashMap2 = new HashMap<>();
        innerHashMap2.put("C", 3);
        innerHashMap2.put("D", 4);
        nestedHashMap.put("Key2", innerHashMap2);

        // 使用流操作对嵌套HashMap进行筛选
        Stream<Map.Entry<String, Map<String, Integer>>> stream = nestedHashMap.entrySet().stream();
        stream.filter(entry -> entry.getKey().equals("Key1")) // 筛选条件：外层HashMap的键为"Key1"
                .flatMap(entry -> entry.getValue().entrySet().stream()) // 扁平化为一个流
                .filter(innerEntry -> innerEntry.getValue() > 1) // 筛选条件：内层HashMap的值大于1
                .forEach(System.out::println); // 输出筛选结果
    }
}