14.6

src/main/java/com/github/hcsp/polymorphism/NameCollector.java

@@ -1,18 +1,18 @@
-package com.github.hcsp.polymorphism;
-
-import java.util.ArrayList;
-import java.util.List;
-import java.util.function.Consumer;
-
-public class NameCollector implements Consumer<User> {
-    private final List<String> names = new ArrayList<>();
-
-    @Override
-    public void accept(User user) {
-        names.add(user.getName());
-    }
-
-    public List<String> getNames() {
-        return names;
-    }
-}
+//package com.github.hcsp.polymorphism;
+//
+//import java.util.ArrayList;
+//import java.util.List;
+//import java.util.function.Consumer;
+//
+//public class NameCollector implements Consumer<User> {
+//    private final List<String> names = new ArrayList<>();
+//
+//    @Override
+//    public void accept(User user) {
+//        names.add(user.getName());
+//    }
+//
+//    public List<String> getNames() {
+//        return names;
+//    }
+//}

src/main/java/com/github/hcsp/polymorphism/User.java

@@ -1,7 +1,9 @@
 package com.github.hcsp.polymorphism;
 
+import java.util.ArrayList;
 import java.util.Arrays;
 import java.util.List;
+import java.util.function.Consumer;
 
 public class User {
     /** 用户ID，数据库主键，全局唯一 */
@@ -26,13 +28,33 @@ public String getName() {
     // 这里使用了一个NameCollector类，请尝试将它改写成匿名内部类
     // 使得代码更加集中，更加容易阅读
     public static List<String> collectNames(List<User> users) {
-        NameCollector collector = new NameCollector();
-        users.forEach(collector);
-        return collector.getNames();
+//        NameCollector collector = new NameCollector();
+//        users.forEach(collector);
+//        return collector.getNames();
+        List<String> names=new ArrayList<>();
+        users.forEach(new Consumer<User>(){
+            public void accept(User user){
+                names.add(user.name);
+            }
+        });
+        return names;
     }
 
     public static void main(String[] args) {
         List<User> users = Arrays.asList(new User(1, "a"), new User(2, "b"));
         System.out.println(collectNames(users));
     }
+//    private static class NameCollector implements Consumer<User> {
+//        private final List<String> names = new ArrayList<>();
+//
+//        @Override
+//        public void accept(User user) {
+//            names.add(user.getName());
+//        }
+//
+//        public List<String> getNames() {
+//            return names;
+//        }
+//    }
+
 }