Question

我有这段代码：

package com.cjburkey.downloads.wie_ein_chef;

import java.awt.FlowLayout;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.beans.PropertyChangeEvent;
import java.beans.PropertyChangeListener;
import java.io.BufferedOutputStream;
import java.io.File;
import java.net.HttpURLConnection;
import java.net.URL;
import java.util.concurrent.ExecutionException;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JOptionPane;
import javax.swing.JProgressBar;
import javax.swing.SwingWorker;

import net.lingala.zip4j.core.ZipFile;
import net.lingala.zip4j.exception.ZipException;

public class Download {

final static JFrame frm = new JFrame();
final static JLabel status = new JLabel("Downloading...");
final static JButton cancel = new JButton("Cancel");
static File fileDown = null;
static String dire = null;

public Download(String site, File file, String dir) {

    fileDown = file;
    dire = dir;
    final JProgressBar current = new JProgressBar(0, 100);
    current.setSize(50, 100);
    current.setValue(0);
    current.setStringPainted(true);
    frm.setSize(640,  480);
    frm.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    frm.setLayout(new FlowLayout());
    frm.add(status);
    frm.add(current);
    frm.add(cancel);
    frm.pack();
    frm.setLocationRelativeTo(null);
    frm.setResizable(false);
    frm.setVisible(true);
    final Worker worker = new Worker(site, file);
    worker.addPropertyChangeListener(new PropertyChangeListener() {
        @Override
        public void propertyChange(PropertyChangeEvent pcEvt) {
            if ("progress".equals(pcEvt.getPropertyName())) {
                current.setValue((Integer) pcEvt.getNewValue());
            } else if (pcEvt.getNewValue() == SwingWorker.StateValue.DONE) {
                try {
                    worker.get();
                } catch (InterruptedException | ExecutionException e) {
                    JOptionPane.showMessageDialog(frm, e.getMessage(), null, JOptionPane.ERROR_MESSAGE);
                    frm.getContentPane().removeAll();
                    frm.dispose();
                    Home.frame.getContentPane().removeAll();
                    Home.frame.repaint();
                    new Home();
                }
            }

        }
    });
    cancel.addActionListener(new ActionListener() {
        public void actionPerformed(ActionEvent e) {
            int option = JOptionPane.showConfirmDialog(frm, "Are you sure you wish to cancel download?");
            if(option == JOptionPane.YES_OPTION) {
                Download.fileDown.delete();
                System.exit(0);
            } else {
                JOptionPane.showMessageDialog(frm, "Resuming");
            }
        }
    });
    worker.execute();
}
}

class Worker extends SwingWorker<Void, Void> {
private String site;
private File file;

public Worker(String site, File file) {
    this.site = site;
    this.file = file;
}

@Override
protected Void doInBackground() throws Exception {
    URL url = new URL(site);
    HttpURLConnection connection = (HttpURLConnection) url.openConnection();
    int filesize = connection.getContentLength();
    int totalDataRead = 0;
    try (java.io.BufferedInputStream in = new java.io.BufferedInputStream(connection.getInputStream())) {
        java.io.FileOutputStream fos = new java.io.FileOutputStream(file);
        try (java.io.BufferedOutputStream bout = new BufferedOutputStream(fos, 1024)) {
            byte[] data = new byte[1024];
            int i;
            while ((i = in.read(data, 0, 1024)) >= 0) {
                totalDataRead = totalDataRead + i;
                bout.write(data, 0, i);
                int percent = (totalDataRead * 100) / filesize;
                Download.status.setText(totalDataRead / 1024 + "kb/" + filesize / 1024 + "kb");
                setProgress(percent);
                Download.frm.setTitle("Downloading File");
                Download.frm.pack();
                Download.frm.setLocationRelativeTo(null);
                if(percent == 100.0) {
                    JButton finish = new JButton("Finish Install(WARNING: WILL OVERRIDE YOU CURRENT MINECRAFT PROFILES)");
                    Download.frm.getContentPane().removeAll();
                    Download.frm.repaint();
                    Download.frm.add(finish);
                    Download.frm.setTitle("Extracting...");
                    Download.frm.pack();
                    Download.frm.setLocationRelativeTo(null);
                    finish.addActionListener(new ActionListener() {
                        public void actionPerformed(ActionEvent e) {
                            Download.status.setText("Waiting");
                            ZipFile file = null;
                            try {
                                file = new ZipFile(Download.fileDown);
                            } catch (ZipException e1) {
                                JOptionPane.showMessageDialog(null, e1.getMessage(), null, JOptionPane.ERROR_MESSAGE);
                            }
                            System.out.println(Download.fileDown.toString());
                            file.setRunInThread(true);
                            try {
                                file.extractAll(Download.dire);
                                JOptionPane.showMessageDialog(null, "Completed Install!!");
                                Download.fileDown.delete();
                                System.exit(0);
                            } catch (ZipException e1) {
                                JOptionPane.showMessageDialog(null, e1.getMessage(), null, JOptionPane.ERROR_MESSAGE);
                            }
                        }
                    });
                }
            }
        }
    }
    return null;
}
}

它过去工作正常，但是现在，当它达到约27％时，它会出错，抱怨价值必须介于0到100之间，但问题是，它用于工作，突然间，它没有。为什么呢？

Answer 1

您遇到的问题是这段代码：

int percent = (totalDataRead * 100) / filesize;
Download.status.setText(totalDataRead / 1024 + "kb/" + filesize / 1024 + "kb");
setProgress(percent);

由于异常消息来自setProgress方法，因此百分比值必须在0 ... 100范围之外： http://docs.oracle.com/javase/7/docs/api/javax/swing/SwingWorker.html#setProgress(int)

注意：

IllegalArgumentException - 值不是0到100

Java值必须介于0到100之间

1 个答案: