java - 等待线程正常完成

Question

我有这个代码:

public class JsoupParser {      
    ArrayList<CompanyInfo> arr = new ArrayList<CompanyInfo>();

    public JsoupParser() {}

    public ArrayList<CompanyInfo> parse(final String link) throws IOException {
        Runnable runnable = new Runnable() {
            public void run() {
                // Here I do some operations and then assign some value
                // to my `arr` ArrayList
            }
        };
        new Thread(runnable).start();

        return arr; // error here, as expected      
    }
}

系统立即返回arr，此时为null。

如何仅在 Thread 完成后才返回 arr？我如何得知Thread已完成？

Answer 1

How can I return arr only after Thread finishes? How can I be informed, that Thread has finished?

Thread parseThread = new Thread(runnable).start();

parseThread.join();

return arr;

您的问题有字面答案，但 zmbq 的答案更适合您的需求。