事情起因：Java端占用内存高，将一堆数据表属性map存起来来，同样的属数据load进Java内存和

C++内存大小差几倍，遂做如下测试：

测试c++ vector,map 与Java List,Map内存占用比较：

C++代码：

测试c++ vector,map 与Java List,Map内存占用比较
C++GS_TEST(LoadMemoryTest2, LoadMemoryTest, LoadMemoryTest, 20240429)
{
	std::vector sds;
	for (int i = 0; i < 10000000; i++)
		sds.push_back(i);
	std::cout << sds.size() << "--"  << std::endl;
}
GS_TEST(LoadMemoryTest3, LoadMemoryTest, LoadMemoryTest, 20240429)
{
	std::map attributes;
	std::vector sds;
	for (int i = 0; i < 10000000; i++)
		attributes[GsStringHelp::ToString(i).c_str()] = GsStringHelp::ToString(i).c_str();
	std::cout << sds.size() << "--" << std::endl;
}
GS_TEST(LoadMemoryTest4, LoadMemoryTest, LoadMemoryTest, 20240429)
{
	std::map attributes;
	std::vector sds;
	for (int i = 0; i < 10000000; i++)
		attributes[GsStringHelp::ToString(i).c_str()] = GsAny(i);
	std::cout << sds.size() << "--" << std::endl;
}

Java：

public static void testarray()
{
	ArrayList data = new 	ArrayList<>();
	for (int i = 0; i < 10000000; i++)
		data.add(i);
	System.console().printf(""+data.size());
}
public static void testarray2()
{
	int[] data = new 	int[10000000];
	for (int i = 0; i < 10000000; i++)
		data[i]=i;
	System.console().printf(""+data.length);
}
public static void testarrayLinkedList()
{
	LinkedList data = new 	LinkedList<>();
	for (int i = 0; i < 10000000; i++)
		data.add(i);
	System.console().printf(""+data.size());
}
public static void testarrayVector()
{
	Vector data = new 	Vector<>();
	for (int i = 0; i < 10000000; i++)
		data.add(i);
	System.console().printf(""+data.size());
}
public static void testarray3HashMap()
{
	HashMap attributes = new HashMap<>();
	for (int i = 0; i < 10000000; i++)
	{
		attributes.put( String.valueOf(i), String.valueOf(i));
	}
	System.console().printf(""+attributes.size());
}
public static void testarray3LinkedHashMap()
{
	LinkedHashMap attributes = new LinkedHashMap<>();
	for (int i = 0; i < 10000000; i++)
	{
		attributes.put( String.valueOf(i), String.valueOf(i));
	}
	System.console().printf(""+attributes.size());
}
public static void testarray3TreeMap()
{
	TreeMap attributes = new TreeMap<>();
	for (int i = 0; i < 10000000; i++)
	{
		attributes.put( String.valueOf(i), String.valueOf(i));
	}
	System.console().printf(""+attributes.size());
}
public static void testarray3HashMapany()
{
	HashMap attributes = new HashMap<>();
	for (int i = 0; i < 10000000; i++)
	{
		attributes.put( String.valueOf(i), new GsAny(i));
	}
	System.console().printf(""+attributes.size());
}

最终比试结果统计：

语言	工作集内存（起始->完成）	峰值内存（起始->完成）
Java(ArrayList)	31M->328M	34M->328M
Java(int[])	31M->70M	34M->70M
Java(LinkedList)	34M->584M	34M-584M
Java(Vector	34M->290M	34M->290M
Java(LinkedHashMap)	34M->2365M	34M->2365M
Java(TreeMap)	34M->2002M	34M->2002M
Java(HashMap)	31M->2112M	34M->2112M
Javav(HashMap)	45M->2593M	45M->2593M
C++(std::vector)	19M->59M	23M->82M
C++(std::map)	19M->1116M	23M->1116M
C++(std::map)	19M->959M	23M->959M

结论：

1. C++ vector内存消耗与Java原生类型数组int[]消耗相当(C++多一点是动态扩容会多扩)
2. Java map存储多消耗2倍多 , ArrayList比std::vector多耗4倍多, 猜测原因Java容器中只能存对象, 有额外装箱和拆箱消耗内存