Java 8将地图的值检索到流和过滤器的数组

Question

有人可以帮助我通过数据流和过滤获取地图值的数组吗？

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名称和title。

Answer 1

如果你需要的TheMap的ArrayList，请尝试以下方法：

ArrayList<TheMap> as = map.values() 
    .stream() 
    .filter(v -> v != null && v.get("name") != null && v.get("title") != null) 
    .map(m -> (TheMap)m) 
    .collect(Collectors.toCollection(ArrayList::new))); 

Answer 2

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