// 接口作为回调函数，C: typdef int (*func)(int,int) AddService func = (int a, int b) -> (a + b); func.add(20, 21); // 多条语句用{}包围 AddService func1 = (int a, int b) -> { System.out.println("count"); return (a + b); }; func1.add(20, 21);

// 1.遍历 // forEach list.forEach((player) -> System.out.println(player));

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

// 2.排序 Arrays.sort(ss, (String s1, String s2) -> (s1.compareTo(s2)));

// 3.线程 new Thread(() -> System.out.println(Thread.currentThread().getName() + ">Say hello")).start(); Runnable th1 = () -> System.out.println(Thread.currentThread().getName() + ">Say world"); th1.run(); }

/** * Stream lambda * 强大的filter条件过滤 */public static void testStream() { // Programmer List progm = new ArrayList() { { add(new Person("Jarrod", "Pace", "PHP programmer", "male", 34, 1550)); add(new Person("Clarette", "Cicely", "PHP programmer", "female", 23, 1200)); add(new Person("Victor", "Channing", "PHP programmer", "male", 32, 1600)); add(new Person("Tori", "Sheryl", "PHP programmer", "female", 21, 1000)); add(new Person("Osborne", "Shad", "PHP programmer", "male", 32, 1100)); add(new Person("Rosalind", "Layla", "PHP programmer", "female", 25, 1300)); add(new Person("Fraser", "Hewie", "PHP programmer", "male", 36, 1100)); add(new Person("Quinn", "Tamara", "PHP programmer", "female", 21, 1000)); add(new Person("Alvin", "Lance", "PHP programmer", "male", 38, 1600)); add(new Person("Evonne", "Shari", "PHP programmer", "female", 40, 1800)); } };

// 定义filter Predicate ageFilter = (p) -> (p.getAge() > 21); // age>21 Predicate salaryFilter = (p) -> (p.getSalary() > 1000); // salary>1000 Predicate genderFilter = (p) -> ("female".equals(p.getGender())); // femail

// 过滤年龄大于21岁且月薪大于$1,000以上的2名女程序员 progm.stream() .filter(ageFilter) .filter(salaryFilter) .filter(genderFilter) .limit(2) // 只取2条记录 .forEach((p) -> System.out.printf("%s %s; ", p.getFirstname(), p.getLastname()));

// 根据姓排序,将结果输出至list List sortprogm = progm .stream() .sorted( (p,p2) -> (p.getFirstname().compareTo(p2.getFirstname()))) .limit(2) .collect( Collectors.toList() );

// 过滤工资最低的程序员 Person per = progm .stream() .min( (p,p2) -> (p.getSalary() - p2.getSalary()) ) .get();

/// map/reduce lambda表达式不可或缺两组函数 // map --> 将姓添加至set Set set = progm .stream() .map(Person::getFirstname) .collect( Collectors.toSet() );

// reduce --> 所有工资的总和 int total = progm .stream() .map( Person::getSalary ) .reduce( 0, (a,b) -> a+b );

// 数组最大最小值，总和，平均值等汇总 List numbers = Arrays.asList(1, 2, 3, 4, 5, 6, 7, 8, 9, 10); IntSummaryStatistics stats = numbers .stream() .mapToInt((x) -> x) .summaryStatistics();}