// 1 数组转map
public static void main(String[] args) {
String backendIdStr="[\"backend-mvj05upv7yc\",\"backend-mvj055qvric\",\"backend-mvj04hlutx4\"]";
String[] backendIdList = JsonUtil.asObject(backendIdStr, String[].class);
Stream<String> stream = Arrays.stream(backendIdList);
Map<String, String> map = stream.collect(Collectors.toMap(key -> key, value -> value));
System.out.println(11111);
}
// 2 List求差集
public static void main(String[] args) {
List<String> list1 = new ArrayList<String>();
list1.add("A");
list1.add("B");
List<String> list2 = new ArrayList<String>();
list2.add("B");
list2.add("C");
list1.removeAll(list2);
System.out.println("交集:" + list1);//差集:[A]
}
// 3 List求交集
public static void main(String[] args) {
List<String> list1 = new ArrayList<String>();
list1.add("A");
list1.add("B");
List<String> list2 = new ArrayList<String>();
list2.add("B");
list2.add("C");
list1.retainAll(list2);
System.out.println("交集:" + list1);//交集:[B]
}
// java 8 处理 :
public void test1(){
List list1=new ArrayList<>();
list1.add(1);
list1.add(2);
list1.add(3);
List list2=new ArrayList<>();
list2.add(3);
list2.add(4);
list2.add(5);
System.out.println("====求交集===");
List list=list1.stream().filter(t->list2.contains(t)).collect(Collectors.toList());
list.stream().forEach(System.out::println);
System.out.println("====求差集===");
list=list1.stream().filter(t-> !list2.contains(t)).collect(Collectors.toList());
list.stream().forEach(System.out::println);
System.out.println("====求并集===");
list.addAll(list1);
list.addAll(list2);
list=list.stream().distinct().collect(Collectors.toList());
list.stream().forEach(System.out::println);
}