public class StreamTest {

    public static void main(String[] args) {

        createStream();

        getForEach();

        getMap();

        getFilter();

        getLimit();

        getSorted();

        getParallel();

        getCollectors();

        getStatistics();

        getSumAll();

    }

    /**

     * 1.生成Stream

     */

    public static void createStream(){

        System.out.println("-------------------->>>>>>>>>>生成Stream");

        List<String> strings = Arrays.asList("abc", "", "bc", "efg", "abcd", "", "jkl");

        List<String> filtered = strings.stream().filter(string -> !string.isEmpty()).collect(Collectors.toList());

        filtered.forEach(System.out::println);

    }

    /**

     * 2.forEach

     */

    public static void getForEach(){

        System.out.println("-------------------->>>>>>>>>>forEach");

        Random random = new Random();

        random.ints().limit(10).forEach(System.out::println);

    }

    /**

     * 3.map

     */

    public static void getMap(){

        System.out.println("-------------------->>>>>>>>>>map");

        List<Integer> numbers = Arrays.asList(3, 2, 2, 3, 7, 3, 5);

        // 获取对应的平方数

        List<Integer> squaresList = numbers.stream().map(i -> i * i).distinct().collect(Collectors.toList());

        squaresList.forEach(System.out::println);

    }

    /**

     * 4.filter

     */

    public static void getFilter(){

        System.out.println("-------------------->>>>>>>>>>filter");

        List<String>strings = Arrays.asList("abc", "", "bc", "efg", "abcd","", "jkl");

        // 获取空字符串的数量

        int count = (int) strings.stream().filter(string -> string.isEmpty()).count();

        System.out.println("空字符串的数量: "+count);

    }

    /**

     * 5.limit

     */

    public static void getLimit(){

        System.out.println("-------------------->>>>>>>>>>limit");

        Random random = new Random();

        random.ints().limit(10).forEach(System.out::println);

    }

    /**

     * 6.sorted

     */

    public static void getSorted(){

        System.out.println("-------------------->>>>>>>>>>sorted");

        Random random = new Random();

        random.ints().limit(10).sorted().forEach(System.out::println);

    }

    /**

     * 7.并行（parallel）程序

     */

    public static void getParallel(){

        System.out.println("-------------------->>>>>>>>>>parallel");

        List<String> strings = Arrays.asList("abc", "", "bc", "efg", "abcd", "", "jkl");

        // 获取空字符串的数量

        int count = (int) strings.parallelStream().filter(string -> string.isEmpty()).count();

        System.out.println("parallel: " + count);

    }

    /**

     * 8.Collectors

     */

    public static void getCollectors(){

        System.out.println("-------------------->>>>>>>>>>Collectors");

        List<String> list = Arrays.asList("abc", "", "bc", "efg", "abcd", "", "jkl");

        List<String> filtered = list.stream().filter(string -> !string.isEmpty()).collect(Collectors.toList());

        System.out.println("筛选列表: " + filtered);

        String mergedString = list.stream().filter(string -> !string.isEmpty()).collect(Collectors.joining(", "));

        System.out.println("合并字符串: " + mergedString);

    }

    /**

     * 9.统计Statistics

     */

    public static void getStatistics(){

        System.out.println("-------------------->>>>>>>>>>Statistics");

        List<Integer> numbers = Arrays.asList(3, 2, 2, 3, 7, 3, 5);

        IntSummaryStatistics stats = numbers.stream().mapToInt((x) -> x).summaryStatistics();

        System.out.println("列表中最大的数 : " + stats.getMax());

        System.out.println("列表中最小的数 : " + stats.getMin());

        System.out.println("所有数之和 : " + stats.getSum());

        System.out.println("平均数 : " + stats.getAverage());

    }

    /**

     * 10.求和集合某个属性

     */

    public static void getSumAll(){

        System.out.println("-------------------->>>>>>>>>>Statistics");

        List<GsonFormatModel> numbers = new ArrayList<>();

        GsonFormatModel gsonFormatModel = new GsonFormatModel();

        gsonFormatModel.setFrom(111);

        numbers.add(gsonFormatModel);

        GsonFormatModel gsonFormatModel1 = new GsonFormatModel();

        gsonFormatModel1.setFrom(999);

        numbers.add(gsonFormatModel1);

        int  stats = numbers.stream().mapToInt(GsonFormatModel::getFrom).sum();

        System.out.println("所有数之和 : " + stats);

    }

}