...Stream对象,然后调用Stream上的方法,filter()过滤得到薪资大于5000的,它的返回值依然是一个Stream,然后通过调用collect()方法并传递一个Collectors.toList...map(Function f) 接收一个函数作为参数,该函数会被应用到每个元素上,并将其映射成一个新的元素。...flatMap(...
list转map /** * If the specified key is not already associated with a value or is * associated with null, associates it wi...
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, Map<K,U>> toMap( Function<? super T, ? extends K> keyMapper, // Key 映射器 Function<? super T, ? extends U> valueMapper // Value 映射器 ) { return toMap(keyMapper, valueMapper, throwingMerger(), HashMap::new); } public static <T, K, U, M extends Map<K, U>> Collector...
list.stream() .filter(user ->user.getId()%2==0) .filter(user ->user.getAge()>10) .map(user ->user.getName().toUpperCase()) .sorted((o1,o2)->{return1;}) .forEach(System.out::println); //sorted 方法中,我们重写compare方法:如果return是1,则是按照原先的排序排。-1则是按照逆序排...
Stream<Person> stream = list.stream(); 1. 2. 2. 数组 通过Arrays类提供的静态函数stream()获取数组的流对象: AI检测代码解析 String[] names = {"chaimm","peter","john"}; Stream<String> stream = Arrays.stream(names); 1. 2. 3. 值 ...
// 一行代码, 把List 转成 Map val subMap = subs.stream().collect(Collectors.toMap(EmployeeJobDTO::getWorkNo, it -> it)); 1. 2. 3. 代码解析 AI检测代码解析 public static <T, K, U> Collector<T, ?, Map<K,U>> toMap( Function<? super T, ? extends K> keyMapper, // Key 映射器...
这里只介绍了Stream,并没有涉及到IntStream、LongStream、DoubleStream,这三个流实现了一些特有的操作符,我将在后续文章中介绍到。 说了这么多,只介绍这些操作符还远远不够;俗话说,实践出真知。那么,Let‘s go。 流的使用详解 对Stream 的使用就是实现一个 filter-map-reduce 过程,产生一个最终结果,或者导致一...
int sum = widgets.stream() .filter(w -> w.getColor() == RED) .mapToInt(w -> w.getWeight()) .sum(); In this example,widgetsis aCollection<Widget>. We create a stream ofWidgetobjects viaCollection.stream(), filter it to produce a stream containing only the red widgets, and then...
Package java.util.stream Description Classes to support functional-style operations on streams of elements, such as map-reduce transformations on collections. For example: int sum = widgets.stream() .filter(b -> b.getColor() == RED) .mapToInt(b -> b.getWeight()) .sum(); ...