add：method reference

Author: MyHerux

src/main/java/com/xu/java8/Stream/Collect.java renamed to src/main/java/com/xu/java8/Practice/Collect.java

@@ -1,6 +1,8 @@
-package com.xu.java8.Stream;
+package com.xu.java8.Practice;
 
 
+import com.xu.java8.Stream.Person;
+
 import java.util.ArrayList;
 import java.util.LinkedHashMap;
 import java.util.List;

src/main/java/com/xu/java8/Practice/Reference.java

@@ -0,0 +1,19 @@
+package com.xu.java8.Practice;
+
+import java.util.function.Predicate;
+import java.util.stream.Stream;
+
+
+public class Reference {
+    public static <T> Predicate<T> as(Predicate<T> predicate) {
+        return predicate;
+    }
+    public static void main(String[] args) {
+        long count = Stream.of("A", "", "B").filter(s -> !s.isEmpty()).count();
+        System.out.println(count);
+        long count1 = Stream.of("A", "", "B").filter(as(String::isEmpty).negate()).count();
+        System.out.println(count1);
+        long count2 = Stream.of("A", "", "B").filter(as(String::isEmpty).negate().and("A"::equals)).count();
+        System.out.println(count2);
+    }
+}