英文:
Hash Map object list iteration using Java 8 Streams
问题
我必须迭代HashMap对象列表。如果映射对象的值为true，则必须使用Java 8 Stream API将该条目返回到一个映射哈希对象中。
public class HashMapCheck {
static Map<String, Boolean> map;
static Map<String, Boolean> map2;
static List<Map> objMap;
public static void main(String args[]) {
map = new HashMap<String, Boolean>();
map.put("1", true);
map.put("2", false);
map2 = new HashMap<String, Boolean>();
map2.put("4", true);
map2.put("5", true);
objMap = new ArrayList<Map>();
objMap.add(map);
objMap.add(map2);
// 迭代部分
}
}
英文:
I have to iterate the HashMap object list. if the map object value is true then I have to return that entry to one map Hash object using java 8 stream API
public class HashMapCheck {
static Map<String, Boolean> map;
static Map<String, Boolean> map2;
static List<Map> objMap;
public static void main(String args[]) {
map = new HashMap<String, Boolean>();
map.put("1", true);
map.put("2", false);
map2 = new HashMap<String, Boolean>();
map2.put("4", true);
map2.put("5", true);
objMap = new ArrayList<Map>();
objMap.add(map);
objMap.add(map2);
//Iterate
}
}
答案1
得分: 0
我对Java流处理不是很熟悉，所以也许这不是最简洁的解决方案，但以下是我使用流处理想出来的代码，以获取我认为你想要的结果：
public class HashMapCheck {
static Map<String, Boolean> map;
static Map<String, Boolean> map2;
static List<Map<String, Boolean>> objMap;
public static void main(String[] args) {
map = new HashMap<>();
map.put("1", true);
map.put("2", false);
map2 = new HashMap<>();
map2.put("4", true);
map2.put("5", true);
objMap = new ArrayList<>();
objMap.add(map);
objMap.add(map2);
Map<String, Boolean> result = objMap.stream().flatMap(x -> x.entrySet().stream()).filter(Map.Entry::getValue).
collect(Collectors.toMap(Map.Entry::getKey, Map.Entry::getValue));
System.out.println(result);
}
}
结果：
{1=true, 4=true, 5=true}
英文:
I'm not an expert with Java streams, so maybe this is not the minimal solution, but here's what I came up with using streams to get what I think you want:
public class HashMapCheck {
static Map<String, Boolean> map;
static Map<String, Boolean> map2;
static List<Map<String, Boolean>> objMap;
public static void main(String[] args) {
map = new HashMap<>();
map.put("1", true);
map.put("2", false);
map2 = new HashMap<>();
map2.put("4", true);
map2.put("5", true);
objMap = new ArrayList<>();
objMap.add(map);
objMap.add(map2);
Map<String, Boolean> result = objMap.stream().flatMap(x -> x.entrySet().stream()).filter(Map.Entry::getValue).
collect(Collectors.toMap(Map.Entry::getKey, Map.Entry::getValue));
System.out.println(result);
}
}
Result:
{1=true, 4=true, 5=true}
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