java做带进度条的上传

(目录)

Java可以使用Swing的JProgressBar组件来实现带进度条的上传功能。

以下是一个简单的示例代码：

import javax.swing.*;
import java.awt.*;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.IOException;

public class FileUploadWithProgressBar extends JFrame {
    private JLabel label;
    private JProgressBar progressBar;
    private JButton uploadButton;

    public FileUploadWithProgressBar() {
        setTitle("文件上传");
        setSize(300, 150);
        setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        setLayout(new FlowLayout());

        label = new JLabel("选择文件：");
        progressBar = new JProgressBar(0, 100);
        uploadButton = new JButton("上传");

        add(label);
        add(progressBar);
        add(uploadButton);

        uploadButton.addActionListener(new ActionListener() {
            @Override
            public void actionPerformed(ActionEvent e) {
                JFileChooser fileChooser = new JFileChooser();
                fileChooser.setDialogTitle("选择文件");
                int selection = fileChooser.showOpenDialog(null);
                if (selection == JFileChooser.APPROVE_OPTION) {
                    File file = fileChooser.getSelectedFile();
                    uploadFile(file);
                }
            }
        });
    }

    private void uploadFile(File file) {
        SwingWorker<Void, Integer> worker = new SwingWorker<Void, Integer>() {
            @Override
            protected Void doInBackground() throws Exception {
                FileInputStream inputStream = null;
                FileOutputStream outputStream = null;

                try {
                    long fileSize = file.length();
                    long uploadedSize = 0;

                    inputStream = new FileInputStream(file);
                    outputStream = new FileOutputStream("path/to/save/file");

                    byte[] buffer = new byte[1024];
                    int bytesRead;

                    while ((bytesRead = inputStream.read(buffer)) != -1) {
                        outputStream.write(buffer, 0, bytesRead);
                        uploadedSize += bytesRead;

                        int progress = (int) (uploadedSize * 100 / fileSize);
                        publish(progress);
                    }
                } catch (IOException ex) {
                    ex.printStackTrace();
                } finally {
                    if (inputStream != null) {
                        try {
                            inputStream.close();
                        } catch (IOException ex) {
                            ex.printStackTrace();
                        }
                    }
                    if (outputStream != null) {
                        try {
                            outputStream.close();
                        } catch (IOException ex) {
                            ex.printStackTrace();
                        }
                    }
                }
                return null;
            }

            @Override
            protected void process(java.util.List<Integer> chunks) {
                int progress = chunks.get(chunks.size() - 1);
                progressBar.setValue(progress);
            }

            @Override
            protected void done() {
                progressBar.setValue(100);
                JOptionPane.showMessageDialog(null, "文件上传完成！");
            }
        };

        worker.execute();
    }

    public static void main(String[] args) {
        SwingUtilities.invokeLater(new Runnable() {
            @Override
            public void run() {
                FileUploadWithProgressBar frame = new FileUploadWithProgressBar();
                frame.setVisible(true);
            }
        });
    }
}

通过使用Swing的JProgressBar组件显示上传进度，并使用SwingWorker来在后台线程中执行文件上传操作。在doInBackground()方法中，通过FileInputStream读取文件内容，并通过FileOutputStream将文件内容写入到指定路径。在每次写入文件内容之后，使用publish()方法来更新上传进度，然后在process()方法中更新进度条的值。最后，在done()方法中设置进度条的值为100，并弹出提示框显示上传完成的消息，代码中的"path/to/save/file"替换保存文件的路径。