vlambda博客
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（Type1 param1, Type2 param2, ..., TypeN paramN）-> {声明1; 声明2; ...... return mentmentM;}

（param1, param2, ..., paramN）-> {指令1; 指令2; ......}

param-> {指令1; 指令2; ......}

param-> 指令1;

// 1.不需要的参数，返回变量5() -> 5
// 2.接收一个参数（数字类型），返回其2倍的值x -> 2 * x
// 3.接受2个参数（数字），并返回他们的差值(x，y) -> x-y
// 4.接收2个int型整数，返回他们的和(int x, int y) -> x + y
// 5.接受一个字符串对象，并在控制台打印，不返回任何值（看起来像是返回void）(String s)-> System.out.print(s)

public class LambdaDemo {
 public static void main(String[] args) { runDemo(); }
 public static void runDemo() { //传统定义 Runnable runnableJdk7 = new Runnable() { @Override public void run() { System.out.println(Thread.currentThread()); } }; runnableJdk7.run();
 //Lambda 形式 Runnable runnableJdk8 = () -> System.out.println(Thread.currentThread()); runnableJdk8.run(); }
}

public static void score() {
 List<Student> listJdk7 = new ArrayList<>( Arrays.asList( new Student(1, "张三", 41), new Student(2, "王二", 92), new Student(3, "李四", 52), new Student(4, "王五", 81), new Student(5, "赵六", 67) ) );
 Iterator<Student> listIt = listJdk7.iterator(); while (listIt.hasNext()) { Student next = listIt.next(); if (next.getScore().intValue() < 80) { listIt.remove(); } } System.out.println(JSON.toJSONString(listJdk7, SerializerFeature.PrettyFormat));  //以下是Jdk8 Lambda 结合 函数式接口 List<Student> listJdk8 = new ArrayList<>( Arrays.asList( new Student(1, "张三", 41), new Student(2, "王二", 92), new Student(3, "李四", 52), new Student(4, "王五", 81), new Student(5, "赵六", 67) ) ); List<Student> collect = listJdk8.stream().filter(x -> x.getScore() > 80).collect(Collectors.toList()); System.out.println(JSON.toJSONString(collect, SerializerFeature.PrettyFormat)); }

 @Override public final Stream<P_OUT> filter(Predicate<? super P_OUT> predicate) { Objects.requireNonNull(predicate); return new StatelessOp<P_OUT, P_OUT>(this, StreamShape.REFERENCE, StreamOpFlag.NOT_SIZED) { @Override Sink<P_OUT> opWrapSink(int flags, Sink<P_OUT> sink) { return new Sink.ChainedReference<P_OUT, P_OUT>(sink) { @Override public void begin(long size) { downstream.begin(-1); }
 @Override public void accept(P_OUT u) { if (predicate.test(u)) downstream.accept(u); } }; } }; }

@FunctionalInterfacepublic interface Predicate<T> {
 /** * Evaluates this predicate on the given argument. * * @param t the input argument * @return {@code true} if the input argument matches the predicate, * otherwise {@code false} */ boolean test(T t);  ...}

x -> x.getScore() > 80