Lambda表达式

Author: enjoyCoding666

src/main/java/com/lambda/LambdaForeach.java

@@ -0,0 +1,13 @@
+package com.lambda;
+
+import java.util.Arrays;
+import java.util.List;
+
+public class LambdaForeach {
+    public static void main(String[] args) {
+        List<Integer> list = Arrays.asList(1, 2, 3, 4, 5, 6, 7);
+        list.forEach(x-> System.out.println(x));
+//      也可以使用双冒号::
+//      list.forEach(System.out::println);
+    }
+}

src/main/java/com/lambda/LambdaForeach2.java

@@ -0,0 +1,16 @@
+package com.lambda;
+
+import java.util.Arrays;
+import java.util.List;
+
+public class LambdaForeach2 {
+    public static void main(String[] args) {
+        List<Integer> list = Arrays.asList(1, 2, 3, 4, 5, 6, 7);
+        list.forEach(x->{
+              if(x>2){
+                  System.out.println(x);
+             }
+        });
+
+    }
+}

src/main/java/com/lambda/LambdaRunnable.java

@@ -0,0 +1,19 @@
+package com.lambda;
+
+public class LambdaRunnable {
+    public static void main(String[] args) {
+        Runnable race2 = () -> System.out.println("Hello world !");
+        race2.run();
+
+//        传统的代码表现方式如下：
+//        Runnable race1 = new Runnable() {
+//            @Override
+//            public void run() {
+//                System.out.println("Hello world !");
+//            }
+//        };
+//        race1.run
+
+
+    }
+}

src/main/java/com/lambda/LambdaSort.java

@@ -0,0 +1,22 @@
+package com.lambda;
+
+import java.util.Arrays;
+import java.util.Collections;
+import java.util.Comparator;
+
+public class LambdaSort {
+    public static void main(String[] args) {
+        String[] players = {"Rafael Nadal", "Novak Djokovic",
+                "Richard Gasquet", "John Isner"};
+
+        // 1.2 使用 lambda expression 排序 players
+        Comparator<String> sortByName = (String s1, String s2) -> (s1.compareTo(s2));
+        Arrays.sort(players, sortByName);
+
+
+        // 1.3 也可以采用如下形式:
+//        Arrays.sort(players, (String s1, String s2) -> (s1.compareTo(s2)));
+
+
+    }
+}

src/main/java/com/lambda/LambdaThread.java

@@ -0,0 +1,10 @@
+package com.lambda;
+
+public class LambdaThread {
+    public static void main(String[] args) {
+        new Thread(
+                () -> System.out.println("New thread")
+        ).start();
+        System.out.println("Main thread");
+    }
+}

src/main/java/com/lambda/StreamMap.java

@@ -0,0 +1,11 @@
+package com.lambda;
+
+import java.util.Arrays;
+import java.util.List;
+
+public class StreamMap {
+    public static void main(String[] args) {
+        List<Integer> list = Arrays.asList(1,2,3,4,5,6,7);
+        list.stream().map( (x) -> x*x ).forEach(System.out::println);
+    }
+}

src/main/java/com/lambda/StreamReduce.java

@@ -0,0 +1,22 @@
+package com.lambda;
+
+import java.util.Arrays;
+import java.util.List;
+
+public class StreamReduce {
+    public static void main(String[] args) {
+        List<Integer> list = Arrays.asList(1,2,3,4,5,6,7);
+        int sum = list.stream().map( x -> x*x ).reduce( (x,y) -> x + y).get();
+        System.out.println(sum);
+      
+//          传统的代码表现方式如下：
+//          List<Integer> list = Arrays.asList(1,2,3,4,5,6,7);
+//          int sum = 0;
+//          for(Integer n : list) {
+//              int x = n * n;
+//              sum = sum + x;
+//          }
+//          System.out.println(sum);
+
+    }
+}