enhance CollUtil.zip

CHANGELOG.md

@@ -6,6 +6,8 @@
 ## 4.6.3
 
 ### 新特性
+* 【core】        改进CollUtil.zip逻辑，减少内存复制（issue#I10T01@Gitee）
+
 ### Bug修复
 * 【http】         修复HttpRquest中body方法长度计算问题（issue#I10UPG@Gitee）
 

hutool-core/src/main/java/cn/hutool/core/collection/CollUtil.java

@@ -1517,13 +1517,14 @@ public class CollUtil {
 			return null;
 		}
 
-		final List<K> keyList = new ArrayList<K>(keys);
-		final List<V> valueList = new ArrayList<V>(values);
+		int entryCount = Math.min(keys.size(), values.size());
+		final Map<K, V> map = newHashMap(entryCount);
 		
-		final int size = Math.min(keys.size(), values.size());
-		final Map<K, V> map = new HashMap<K, V>((int) (size / 0.75));
-		for (int i = 0; i < size; i++) {
-			map.put(keyList.get(i), valueList.get(i));
+		final Iterator<K> keyIterator = keys.iterator();
+		final Iterator<V> valueIterator = values.iterator();
+		while (entryCount > 0) {
+			map.put(keyIterator.next(), valueIterator.next());
+			entryCount--;
 		}
 
 		return map;

hutool-core/src/test/java/cn/hutool/core/collection/CollUtilTest.java

@@ -571,4 +571,19 @@ public class CollUtilTest {
 		String last = CollUtil.getLast(test);
 		Assert.assertNull(last);
 	}
+
+	@Test
+	public void zipTest() {
+		Collection<String> keys = CollUtil.newArrayList("a", "b", "c", "d");
+		Collection<Integer> values = CollUtil.newArrayList(1, 2, 3, 4);
+		
+		Map<String, Integer> map = CollUtil.zip(keys, values);
+		
+		Assert.assertEquals(4, map.size());
+		
+		Assert.assertEquals(1, map.get("a").intValue());
+		Assert.assertEquals(2, map.get("b").intValue());
+		Assert.assertEquals(3, map.get("c").intValue());
+		Assert.assertEquals(4, map.get("d").intValue());
+	}
 }