您好我已经使用循环创建了一个等待队列模拟，并且我已经使用GUI点击运行按钮的问题是什么，没有显示几秒钟的情况，例如10-15秒然后整个输出显示在JTextArea中。如何在控制台中输出附加到jtextarea的所有内容。我查找了一个名为SwingWorker的东西。但不知道如何使用它。请帮助。
package Windows;
import java.awt.Container;
import java.awt.Dimension;
import java.awt.GridLayout;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.text.DateFormat;
import java.text.SimpleDateFormat;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.Calendar;
import java.util.LinkedList;
import java.util.Queue;
import java.util.Random;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.JScrollPane;
import javax.swing.JTextArea;
public class Station implements ActionListener
{
private JTextArea userinput, useroutput;
private JScrollPane sbr_userinput, sbr_useroutput;
private JButton runButton, clearButton, homeButton;
//LinkedList Customer Queue created here.
public static Queue<String> line = new LinkedList<String> ();
private static String time; //time variable.
private static DateFormat dateFormat = new SimpleDateFormat("HH:mm:ss"); //DateFormat variable.
private int intervals;
private int cashiers;
private int processing_time;
public static void main(String[] args)
{
new Station();
}
public Station()
{
JFrame frame = new JFrame("[=] Train Station Simulation [=]");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setSize(800, 400);
frame.setContentPane(GUI());
frame.setVisible(true);
}
public Container GUI()
{
JPanel totalGUI = new JPanel();
totalGUI.setLayout(new GridLayout(1, 2, 3, 3));
JPanel lPanel = new JPanel();
lPanel.setLayout(new GridLayout(2, 1, 3 , 3));
totalGUI.add(lPanel);
JPanel rPanel = new JPanel(new GridLayout(3, 1, 3 , 3));
totalGUI.add(rPanel);
userinput = new JTextArea("Welcome to Train Station Queue Simulation!!!" + "\n" +
"Enter the number of cashiers available HERE!!!!:" + "\n");
userinput.setEditable(true);
userinput.setLineWrap(true);
userinput.setWrapStyleWord(true);
lPanel.add(userinput);
useroutput = new JTextArea();
useroutput.setEditable(false);
useroutput.setLineWrap(true);
useroutput.setWrapStyleWord(true);
lPanel.add(useroutput);
sbr_userinput = new JScrollPane(userinput, JScrollPane.VERTICAL_SCROLLBAR_AS_NEEDED,
JScrollPane.HORIZONTAL_SCROLLBAR_AS_NEEDED);
sbr_userinput.setPreferredSize(new Dimension(300, 300));
lPanel.add(sbr_userinput);
sbr_useroutput = new JScrollPane(useroutput, JScrollPane.VERTICAL_SCROLLBAR_AS_NEEDED,
JScrollPane.HORIZONTAL_SCROLLBAR_AS_NEEDED);
sbr_useroutput.setPreferredSize(new Dimension(300, 300));
lPanel.add(sbr_useroutput);
runButton = new JButton("RUN");
runButton.addActionListener(this);
rPanel.add(runButton);
clearButton = new JButton("CLEAR");
clearButton.addActionListener(new ActionListener()
{
public void actionPerformed(ActionEvent e)
{
userinput.setText("");
useroutput.setText("");
System.out.println("cleared");
}
});
rPanel.add(clearButton);
homeButton = new JButton("HOME");
rPanel.add(homeButton);
totalGUI.setOpaque(true);
return totalGUI;
}
public void actionPerformed(ActionEvent e)
{
cashiers = Integer.parseInt(userinput.getText());
if (e.getSource() == this.runButton)
{
useroutput.append("CUSTOMERS ARE COMING !!!! !!!!" + "\n" + "\n");;
//Array of all the customer that will enter the queue.
String list[] = {"Naqi", "Monty", "Mohin", "Yasmin", "Maighjoo", "Ashish", "Paal", "Kevin", "Ruhail", "Tony"};
//2nd ArrayList which customer are added to and removed later on so no duplicates arise.
ArrayList<String> customer = new ArrayList<String>(Arrays.asList(list));
int array_customer_list = list.length; //Recording the number of customers in the array.
//While statement containing for loop add customers to the empty LinkedList object.
while (line.isEmpty())
{
for (int x = 0; x < array_customer_list; x++ )
{
try
{
Thread.sleep(ran_interval() * 1000); //Sleep method to hold the arrival time by 1-2 seconds.
int cus = (int) (Math.random() * customer.size()); //Random customer is picked here.
String new_cus = customer.get(cus); //New customer object is created ere.
line.add(new_cus); //Customer objects are added to the empty LinkedList queue.
customer.remove(cus);
//For loop statement to outputting the queue.
for (String s : line)
{
useroutput.append("[" + s.toString() + " " + "]" + "\n");; //Outputting each customer and using the ".name" method so customers are readable.
}
//Outputting the whole queue and stating who has joined the queue.
useroutput.append("\n" + "The queue has " + line.size() + " customers so far" + "\n" +
new_cus.toString() + " Has Joined the Queue " + " <=== WAITING" + "\n" + "\n");
}
catch(Exception a) //ERROR handler for sleep method.
{
System.out.println("Intervals error: " + e); //Outputting the ERROR message.
System.exit(0); //If ERROR found exit system.
}
}
}
userinput.append("\n");
useroutput.append("CUSTOMERS ARE WAITING !!!! !!!!" + "\n" + "\n");
useroutput.append("Processing START !!!!" + "\n" + "\n");
while (!line.isEmpty()) //While statement with for loop to remove each customer from LinkedList queue.
{
try
{
String cus = line.remove(); //Method to remove customer from LinkedList queue.
String time = getTime();
Thread.sleep((processing_time() * 1000) / cashiers); //Sleep method to hold the processing by 1-3 seconds.
for (String s : line)
{
useroutput.append("[" + s.toString() + " " + "]" + "\n"); //Outputting each customer and using the ".name" method so customers are readable.
}
//Outputting the whole queue and stating who has joined the queue.
useroutput.append("\n" + "The queue has " + line.size() + " customers left" + "\n" +
cus.toString()+ " waited for " + time + " <=== SERVED" + "\n" + "\n");
}
catch(Exception a) //ERROR handler for sleep method.
{
System.out.println("Cashiers_wait error: " + e); //Outputting the ERROR message.
System.exit(0); //If ERROR found exit system.
}
}
}
useroutput.append("Processing FINISHED !!!!" + "\n");
System.out.println("working");
}
static String getTime() //Time Constructor
{
Calendar cal = Calendar.getInstance();
time = dateFormat.format(cal.getTime()); //Getting the current system time.
return time; //Return time.
}
public int ran_interval()
{
Random rand = new Random(); //Random object created here.
int interval = this.intervals = rand.nextInt(2) + 1; //Random number between 1-2 is generated for customer arrival here.
return interval;
}
public int processing_time()
{
Random ran = new Random(); //Random object created here.
int time = this.processing_time = ran.nextInt(4) + 1; //Random number between 1-3 is generated for customer arrival here.
return time;
}
}
答案 0 :(得分：4)
Swing是一个单线程框架。也就是说，与UI的所有交互都是在事件调度线程的上下文中执行的。
EDT的职责之一是处理重绘请求。
阻止此线程的任何进程都将阻止它更新UI。
在您的actionPerformed方法中，您在EDT中运行了一个耗时的过程，这就是为什么在您看到结果之前需要一些时间
Yu可以启动第二个线程并在那里处理数据，允许EDT继续响应更新请求。问题是，Swing还要求对ED的任何修改也要在EDT中执行。
幸运的是，有一个简单的解决方案。
最好的选择是使用SwingWorker。它有一个doInBackground方法，允许您处理EDT，publish方法允许您将结果发送回EDT，process方法处理正在发布的内容，在EDT中执行的done方法，当doInBackground方法存在时，在EDT的上下文中调用
请查看Concurrency in Swing了解详情
答案 1 :(得分：1)
您可以使用模型视图类型的程序设计。基本上，您有2个线程：一个处理GUI（视图/控制器），另一个线程处理数据（模型）。当在GUI中执行操作时，您启动第二个线程并告诉它对数据进行处理。然后，当数据模型线程开始更改值时，它告诉GUI线程通过发送某种事件来更新GUI。
有关模型 - 视图 - 控制器设计的更多信息，请参阅http://en.wikipedia.org/wiki/Model%E2%80%93view%E2%80%93controller
在伪代码中，这是如何工作的：
GUI线程
Initialize UI
While program is running
Wait for event (like action performed, or ready to update event)
If button was pressed
Add task to data model's work queue
Else // Was not a button event, so therefore the data model must
// have sent an update
Set values in GUI components using the updated data
Repaint GUI
数据模型线程（通常有一个工作队列，GUI线程可以用来告诉它该做什么）
While model has work to do
Work on next task // and manipulate data
Send update event to GUI
如您所见，如果您从一开始就纳入这个想法，这将更容易实现。
“解决”此问题的另一种方法是，只要您希望UI立即更新，就可以设置此调用：
frame.paint(frame.getGraphics());
但是，这是一个hack，因为JFrame.paint和JFrame.getGraphics都是内部Swing方法，所以除非你别无选择，否则不应该使用它。如果你过于频繁地调用它，它确实会产生令人讨厌的闪烁效果/屏幕撕裂，因为你在计算机将像素数据发送到显示器的同时更新像素数据。 （大多数计算机每秒执行大约30-60次。）