java-8 - Java 8 使用流和过滤器将 Map 的值检索到数组中

Question

有人会帮助我通过流和过滤获取 map 值的数组吗？

public class TheMap extends HashMap<String, String> {
    public TheMap(String name, String title) {
        super.put("name", name);
        super.put("title", title);
    }

    public static void main(final String[] args) {
        Map<Long, Map<String, String>>map = new HashMap<>();            

        map.put(0L, null);
        map.put(1L, new TheMap("jane", "engineer"));
        map.put(2L, new TheMap("john", "engineer"));
        map.put(3L, new TheMap(null, "manager"));
        map.put(4L, new TheMap("who", null));
        map.put(5L, new TheMap(null, null));
    }
}

我正在寻找的结果是 ArrayList<TheMap>只有这两个条目:

TheMap("jane", "engineer")
TheMap("john", "engineer")

基本上，检索 TheMap与 none-null姓名和 title .

Answer 1

List<Map<String, String>> list = 
        map.values().stream().filter(v -> 
                              v != null && 
                              !v.entrySet().isEmpty() &&
                              !v.containsValue(null)).
        collect(Collectors.toList());