阅读：https://blog.csdn.net/u013541140/article/details/102710138

 1     public static void main(String[] args) {

         // ‘代替匿名类’

 //        new Thread(() -> System.out.println("java8 lambda")).start();

         // ‘list 遍历集合’

         List features = Arrays.asList("Lambdas", "Default Method", "Stream API", "Date and Time API");

 //        features.forEach(n -> System.out.println(n));

         // ‘函数接口 filter’

         List languages = Arrays.asList("Java", "Scala", "C++", "Haskell", "Lisp");

         Predicate<String> predicate = str -> str.equals("Java");

 //        languages.stream().filter(n -> predicate.test((String) n)).forEach(n -> System.out.println(n));

         //’通过filtering 创建一个字符串String的集合，需要找个变量接受一下

         List<String> tempString = (List<String>) languages.stream().filter(n -> predicate.test((String) n)).collect(Collectors.toList());

 //        tempString.forEach(System.out::println);

         //map允许你改变你内部元素

         List<Integer> costBeforeTax = Arrays.asList(100, 200, 300, 400, 500);

 //        costBeforeTax.stream().map((n) -> n + n * 12).forEach(n -> System.out.println(n));

         //reduce 可以理解成 sql的函数

         Integer tempSum = costBeforeTax.stream().map((n) -> n + n * 12).reduce((sum,n1)->sum + n1).get();

         //summaryStatistics包含最大值最小值，总和及平均值

         IntSummaryStatistics stats = costBeforeTax.stream().mapToInt(n->n).summaryStatistics();

         System.out.println("Highest prime number in List : " + stats.getMax());

         System.out.println("Lowest prime number in List : " + stats.getMin());

         System.out.println("Sum of all prime numbers : " + stats.getSum());

         System.out.println("Average of all prime numbers : " + stats.getAverage());

         //function函数Function<T,R>    输入T返回R

         Function<String,String> function = n-> n + "jack";

         System.out.println(function.apply("String"));

     }