Question

我对多线程很新。我目前正在开发一个项目，该项目需要启动一个线程，并在完成时通知启动它的线程并继续执行。我尝试使用布尔变量并指示系统打印出一些字符串以指示操作阶段。找到下面的代码

public class BankDatabaseSQL {
private Connection connection;
private ResultSet resultSet;

private static final String URL = "jdbc:mysql://localhost/banktesting";
private static final String USERNAME = "root";

Account account;

public final Object monitor = new Object();

private PreparedStatement setBalance;
private PreparedStatement getAccount;
int numberOfRows;

/** code omitted **/

/**
   method in question
*/
public synchronized boolean authenticatePrint(){

    try{
        MainForm mainForm = new MainForm();
        do{
        ExecutorService threadExecutor = Executors.newCachedThreadPool();
        mainForm.accNo = account.getAccountNumber();
        threadExecutor.execute(mainForm);
        wait(); 
        }while(mainForm.verified = false); // while the verified variable of the mainForm object is set to false,
                                           // the thread should keep waiting. The process has not gotten into this
                                           // if statement. 
        if(mainForm.verified = true){

            System.out.println("time to notify");
            notify();
        }

应该进行通知的第二种方法如下所示

public class MainForm extends JFrame implements Runnable
{
 public void run() {
        new MainForm();

}
public synchronized void onVerify() {
    VerificationForm form = new VerificationForm(this);
    form.setVisible(true);
            System.out.println("\nTime to onVerify");
            if(form.verificationStatus = true){
                verified = true; // variable for the mainForm object to aid in notifying the thread
                System.out.println("\nVerified = true has been set!");

            }

    }
}

Answer 1

尝试在主线程中调用join()，如下所示：

mainThread.join（）

它将等待其他线程完成，然后主线程继续执行。

但尝试使用其他多线程技术，例如CountDownLatch，Barrier或Cyclic。

Java - 从内部线程通知外部线程

1 个答案: