java - 与 Java 并行创建对象

Question

在Java中，我有一个代码:

Graph[] graphs = new Graph[100];
for (int i = 0; i < 100; i++) {
    graphs[i] = new Graph();
    Graph g = graphs[i];
    g.subgraphs = new Graph[100 - i];
    g.leaves = new HashSet<Integer>();
    g.targets = new HashMap<Integer, int[]>(l - i);
    g.weights = new HashMap<Integer, Integer>(l - i);
}

我想写一个并行代码。你能帮我学习 Java 线程吗？所以我添加了这段代码:

Thread[] threads = new Thread[3];
for (int i = 0; i < threads.length; i++) {
    threads[i] = new Thread(new Runnable() {
        public void run() {
            // some code to run in parallel
        }
    });
    threads[i].start();
}

// as far as I understood this waits until threads above are finishing
for (int i = 0; i < threads.length; i++) {
    try {
        threads[i].join();
    } catch (InterruptedException e) {
        e.printStackTrace();
    }
}

现在，当我创建自定义 Graph 对象时，我可以从循环中复制代码，但我需要以某种方式传递索引 i (来自 0 到 100) 到 run() 方法。

我怎样才能做到这一点？

Answer 1

如果您的目标是最大限度地提高性能，那么您最好的选择几乎肯定是这里完全不进行并行。创建几百个 HashMap 几乎肯定比启动任何新线程更便宜。