CollectionsTest

whatsmars-common/src/test/java/org/hongxi/java/util/collections/CollectionsTest.java

@@ -0,0 +1,55 @@
+package org.hongxi.java.util.collections;
+
+import org.junit.Test;
+
+/**
+ * @author shenhongxi 2019/8/13
+ */
+public class CollectionsTest {
+
+    @Test
+    public void testArrayList() {
+        ArrayList arrList = new ArrayList();
+        arrList.add(1);
+        arrList.add(2);
+        arrList.add(3);
+        arrList.add(null);
+        System.out.println(arrList);
+    }
+
+    @Test
+    public void testLinkedList() {
+        LinkedList<Integer> list = new LinkedList<>();
+        list.add(1);
+        list.add(2);
+        list.add(3);
+        System.out.println(list);
+        list.reverse();
+        System.out.println(list);
+    }
+
+    @Test
+    public void testHashMap() {
+        HashMap<Integer, String> map = new HashMap<>();
+        map.put(1, "first");
+        map.put(2, "second");
+        System.out.println(map.get(1));
+        System.out.println(map.size());
+        System.out.println(map.containsKey(1));
+        System.out.println(map.containsValue("first"));
+        System.out.println(map.remove(1));
+        System.out.println(map.remove(2));
+        System.out.println(map.isEmpty());
+    }
+
+    @Test
+    public void testStack() {
+        Stack<Integer> stack = new Stack<>();
+        stack.push(1);
+        stack.push(2);
+        stack.push(3);
+        System.out.println(stack.pop());
+        System.out.println(stack.pop());
+        System.out.println(stack.pop());
+    }
+}