import java.util.ArrayList;
import java.util.List;
import java.util.concurrent.ConcurrentHashMap;
import java.util.stream.IntStream;

public class Survey {

    public static void main(String[] args) {
        ConcurrentHashMap<String, List<ConcurrentHashMap<String, Object>>> testMap = new ConcurrentHashMap<>();

        long start = 0;
        long end = 0;
        // 先垃圾回收
        System.gc();
        start = Runtime.getRuntime().freeMemory();
        IntStream.range(0, 4000).forEach(i -> {
            String topic = "market.eosusdt.kline.1min" + i;
            ConcurrentHashMap<String, Object> data = new ConcurrentHashMap<>();
            data.put("id", 1537325760);
            data.put("open", 5.1214);
            data.put("close", 5.1199);
            data.put("low", 5.117);
            data.put("high", 5.1223);
            data.put("amount", 1947.6461);
            data.put("vol", 9972.01690388);
            data.put("count", 18);

            List<ConcurrentHashMap<String, Object>> datas = new ArrayList<>();

            IntStream.range(0, 2000).forEach(j -> datas.add(data));

            testMap.put(topic, datas);
        });
        // 快要计算的时,再清理一次
        System.gc();
        end = Runtime.getRuntime().freeMemory();
        System.out.println("占内存:" + (end - start) / 1000.0 + "M");
    }
}