我曾经使用进度条来监视长时间运行的任务，这个任务当然是在Swingworker线程中执行的。
现在你可以在所有情况下使用
SwingWorker将任何繁重和长时间运行的任务重定向到
Background。
import java.awt.*;
import java.util.*;
import javax.swing.*;
import javax.swing.table.*;
public class TableCellProgressBar {
private String[] columnNames = {"String", "ProgressBar"};
private Object[][] data = {{"dummy", 100}};
private DefaultTableModel model = new DefaultTableModel(data, columnNames) {
private static final long serialVersionUID = 1L;
@Override
public Class<?> getColumnClass(int column) {
return getValueAt(0, column).getClass();
}
@Override
public boolean isCellEditable(int row, int col) {
return false;
}
};
private JTable table = new JTable(model);
public JComponent makeUI() {
TableColumn column = table.getColumnModel().getColumn(1);
column.setCellRenderer(new ProgressRenderer());
EventQueue.invokeLater(new Runnable() {
@Override
public void run() {
startTask("test");
startTask("error test");
startTask("test");
}
});
JPanel p = new JPanel(new BorderLayout());
p.add(new JScrollPane(table));
return p;
}
private void startTask(String str) {
final int key = model.getRowCount();
SwingWorker<Integer, Integer> worker = new SwingWorker<Integer, Integer>() {
private int sleepDummy = new Random().nextInt(100) + 1;
private int lengthOfTask = 120;
@Override
protected Integer doInBackground() {
int current = 0;
while (current < lengthOfTask && !isCancelled()) {
if (!table.isDisplayable()) {
break;
}
if (key == 2 && current > 60) {
cancel(true);
publish(-1);
return -1;
}
current++;
try {
Thread.sleep(sleepDummy);
} catch (InterruptedException ie) {
break;
}
publish(100 * current / lengthOfTask);
}
return sleepDummy * lengthOfTask;
}
@Override
protected void process(java.util.List<Integer> c) {
model.setValueAt(c.get(c.size() - 1), key, 1);
}
@Override
protected void done() {
String text;
int i = -1;
if (isCancelled()) {
text = "Cancelled";
} else {
try {
i = get();
text = (i >= 0) ? "Done" : "Disposed";
} catch (Exception ignore) {
ignore.printStackTrace();
text = ignore.getMessage();
}
}
System.out.println(key + ":" + text + "(" + i + "ms)");
}
};
model.addRow(new Object[]{str, 0});
worker.execute();
}
public static void main(String[] args) {
EventQueue.invokeLater(new Runnable() {
@Override
public void run() {
createAndShowGUI();
}
});
}
public static void createAndShowGUI() {
JFrame frame = new JFrame();
frame.setDefaultCloseOperation(WindowConstants.EXIT_ON_CLOSE);
frame.getContentPane().add(new TableCellProgressBar().makeUI());
frame.setSize(320, 240);
frame.setLocationRelativeTo(null);
frame.setVisible(true);
}
}
class ProgressRenderer extends DefaultTableCellRenderer {
private final JProgressBar b = new JProgressBar(0, 100);
public ProgressRenderer() {
super();
setOpaque(true);
b.setBorder(BorderFactory.createEmptyBorder(1, 1, 1, 1));
}
@Override
public Component getTableCellRendererComponent(JTable table, Object value, boolean isSelected, boolean hasFocus, int row, int column) {
Integer i = (Integer) value;
String text = "Completed";
if (i < 0) {
text = "Error";
} else if (i < 100) {
b.setValue(i);
return b;
}
super.getTableCellRendererComponent(table, text, isSelected, hasFocus, row, column);
return this;
}
}
但是为什么要使用SwingWorker来复杂化Wwing GUI呢？（这需要对Java Essential Classes和Generics有深入的了解）
Runnable#Thread的基本实现只需要使用invokeLater来输出到Swing GUI中，而且如果是从EDT（从Swing/AWT Listener）启动，并且没有任何包含Thread.sleep(int)代码行，则只建议/要求在生产代码中使用invokeLater
import java.awt.Component;
import java.util.Random;
import javax.swing.JFrame;
import javax.swing.JProgressBar;
import javax.swing.JScrollPane;
import javax.swing.JTable;
import javax.swing.SwingUtilities;
import javax.swing.table.DefaultTableModel;
import javax.swing.table.TableCellRenderer;
public class TableWithProgressBars {
public static class ProgressRenderer extends JProgressBar implements TableCellRenderer {
private static final long serialVersionUID = 1L;
public ProgressRenderer(int min, int max) {
super(min, max);
this.setStringPainted(true);
}
@Override
public Component getTableCellRendererComponent(JTable table, Object value,
boolean isSelected, boolean hasFocus, int row, int column) {
this.setValue((Integer) value);
return this;
}
}
private static final int maximum = 100;
public static void main(String[] args) {
SwingUtilities.invokeLater(new Runnable() {
@Override
public void run() {
new TableWithProgressBars().createGUI();
}
});
}
public void createGUI() {
final JFrame frame = new JFrame("Progressing");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
Integer[] oneRow = {0, 0, 0, 0};
String[] headers = {"One", "Two", "Three", "Four"};
Integer[][] data = {oneRow, oneRow, oneRow, oneRow, oneRow,};
final DefaultTableModel model = new DefaultTableModel(data, headers);
final JTable table = new JTable(model);
table.setDefaultRenderer(Object.class, new ProgressRenderer(0, maximum));
table.setPreferredScrollableViewportSize(table.getPreferredSize());
frame.add(new JScrollPane(table));
frame.pack();
frame.setLocationRelativeTo(null);
frame.setVisible(true);
new Thread(new Runnable() {
@Override
public void run() {
Object waiter = new Object();
synchronized (waiter) {
int rows = model.getRowCount();
int columns = model.getColumnCount();
Random random = new Random(System.currentTimeMillis());
boolean done = false;
while (!done) {
int row = random.nextInt(rows);
int column = random.nextInt(columns);
Integer value = (Integer) model.getValueAt(row, column);
value++;
if (value <= maximum) {
model.setValueAt(value, row, column);
try {
waiter.wait(15);
} catch (InterruptedException e) {
e.printStackTrace();
}
}
done = true;
for (row = 0; row < rows; row++) {
for (column = 0; column < columns; column++) {
if (!model.getValueAt(row, column).equals(maximum)) {
done = false;
break;
}
}
if (!done) {
break;
}
}
}
frame.setTitle("All work done");
}
}
}).start();
}
}
对于真正的繁重且长时间运行的任务，你需要查看 Runnable#Thread（简单、易懂、无错误和清晰），只有当你非常熟悉Java和Swing时，才可以考虑使用SwingWorker。
SwingWorker.publish(V...)方法是在doInBackground方法内部使用的，用于将中间结果传递到事件分派线程以在process方法中进行处理。 - Andrew Thompson