增加函数式编程

src/main/java/com/zeekling/function/FunctionTest.java

@@ -0,0 +1,37 @@
+package com.zeekling.function;
+
+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.List;
+
+/**
+ * @author zeekling
+ * @apiNote 函数式编程
+ * @since 2021-07-04
+ */
+public class FunctionTest {
+
+    public static <T> List<T> filter(List<T> list, Predicate<T> p) {
+        List<T> results = new ArrayList<>();
+        for(T s: list){
+            if(p.test(s)){
+                results.add(s);
+            }
+        }
+        return results;
+    }
+
+
+    public static void main(String[] args) {
+        List<String> listOfStrings = new ArrayList<String>(){{
+            add("");
+            add("1");
+            add("2");
+        }};
+        Predicate<String> nonEmptyStringPredicate = (String s) -> !s.isEmpty();
+        List<String> nonEmpty = filter(listOfStrings, nonEmptyStringPredicate);
+        System.out.println(Arrays.toString(nonEmpty.toArray()));
+
+    }
+
+}

src/main/java/com/zeekling/function/Predicate.java

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+package com.zeekling.function;
+
+import java.util.ArrayList;
+import java.util.List;
+
+/**
+ * @author zeekling
+ * @apiNote 函数式编程测试
+ * @since 2021-07-04
+ */
+@FunctionalInterface
+public interface Predicate<T> {
+
+    boolean test(T t);
+
+
+
+}