Stream<String> stream = stringList.stream(); stream.forEach(System.out::println); List <String> sortStrings = stream.sorted(String::compareToIgnoreCase).collect(Collectors.toList()); stream.forEach(System.out::println); } 控制台打印结果为: cd ab ef java.lang.IllegalStateException: stream h...
List<Integer> listNew = list.stream().filter(x -> x % 2 == 0).collect(Collectors.toList()); System.out.println("产生的新集合是:" + listNew); Set<Integer> set = list.stream().filter(x -> x % 2 == 0).collect(Collectors.toSet()); System.out.println("产生的不重复的新集合...
stream() .collect(Collectors.partitioningBy(s -> s.getGrade() >= PASS_THRESHOLD)); } @since 1.8 定义示例数据 操作对象: @Data @AllArgsConstructor public class Person implements Serializable { private static final long serialVersionUID = -5996703909566682313L; private Long id; private String name...
String join2 = dishes.stream().map(Dish::getName).collect(Collectors.joining(", ")); 1. 2. 3. 4. 5. 6. 7. 8. 9. 10. toList List<String> names = dishes.stream().map(Dish::getName).collect(toList()); List<String> names = dishes.stream().map(Dish::getName).collect(toLi...
Map<Long,String>map=userList.stream().collect(Collectors.toMap(User::getId,User::getName)); 这个获取的就是key为id,value为name的map了。 2. 三个参数的用法 还是沿用上面那个例子,如果这个时候你想获取key是age,value是name的map呢?如果你还是沿用上面的方法,就会出问题了,因为有两个age...
这里以一个collect收集器最简单的使用场景来剖析说明下其中的关系: 📢概括来说: 1️⃣collect是Stream流的一个终止方法,会使用传入的收集器(入参)对结果执行相关的操作,这个收集器必须是Collector接口的某个具体实现类 2️⃣Collector是一个接口,collect方法的收集器是Collector接口的具体实现类3️⃣Collect...
将集合通过Stream.collect()转换成其他集合/数组: 现在拿List做例子 转成HashSet: ListuserList=getUserList(); StreamusersStream=userList.stream(); HashSetusersHashSet=usersStream.collect(Collectors.toCollection(HashSet::new)); 转成SetusersSet: ...
将集合通过Stream.collect()转换成其他集合/数组: 现在拿List<UserDTO>做例子 转成HashSet<UserDTO>: List<UserDTO>userList=getUserList(); Stream<UserDTO>usersStream=userList.stream(); HashSet<UserDTO>usersHashSet=usersStream.collect(Collectors.toCollection(HashSet::new)); ...
public static<T> Stream<T> of(T... values) { return Arrays.stream(values); } 1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 1.2 使用Arrays.stream(T[] array) 方法从数组创建 //Arrays.Stream(values),该方法含有重载方法,可截取一部分来创建流 ...
Java Stream collect is a terminal stream operation. It performs a mutable reduction operation on the elements of the stream. Reduction operations can be performed either sequentially or in parallel. CollectorsThe Collectors class contains predefined collectors to perform common mutable reduction tasks. ...