java如何转换图片格式，高分求助，急！！

Question

jdk里有专门的api你可以找找.忘记是啥了。好象是...Stream.class

Answer 1

package com.liming.applet;import java.awt.*;
import java.awt.event.*;
import java.awt.image.*;
import javax.swing.*;
import java.io.*;
import java.net.*;
import javax.imageio.*;public class Converting
    extends JFrame {
    JLabel promptLabel;
    JTextField prompt;
    JButton promptButton;
    JFileChooser fileChooser;
    JComboBox comboBox;
    JButton saveButton;
    public Converting() {
        super("Image Conversion");
        setDefaultCloseOperation(EXIT_ON_CLOSE);
        Container contentPane = getContentPane();
        JPanel inputPanel = new JPanel();
        promptLabel = new JLabel("Filename:");
        inputPanel.add(promptLabel);
        prompt = new JTextField(20);
        inputPanel.add(prompt);
        promptButton = new JButton("Browse");
        inputPanel.add(promptButton);
        contentPane.add(inputPanel, BorderLayout.NORTH);
        fileChooser = new JFileChooser();
        promptButton.addActionListener(new ActionListener() {
            public void actionPerformed(ActionEvent e) {
                int returnValue = fileChooser.showOpenDialog(null);
                if (returnValue == JFileChooser.APPROVE_OPTION) {
                    File selectedFile = fileChooser.getSelectedFile();
                    if (selectedFile != null) {
                        prompt.setText(selectedFile.getAbsolutePath());
                    }
                }
            }
        });
        JPanel outputPanel = new JPanel();
        String writerFormats[] = ImageIO.getWriterFormatNames();
        ComboBoxModel comboBoxModel = new DefaultComboBoxModel(writerFormats);
        comboBox = new JComboBox(comboBoxModel);
        outputPanel.add(comboBox);
        saveButton = new JButton("Save");
        outputPanel.add(saveButton);
        saveButton.addActionListener(new ActionListener() {
            public void actionPerformed(ActionEvent e) {
                try {
                    String name = prompt.getText();
                    File file = new File(name);
                    if (file.exists()) {
                        BufferedImage image = ImageIO.read(file.toURL());
                        if (image == null) {
                            System.err.println(
                                "Invalid input file format");
                        }
                        else {
                            String selection = (String
                                                ) comboBox.getSelectedItem();
                            String outputFilename = name + "." + selection;
                            File outputFile = new File(outputFilename);
                            boolean found = ImageIO.write(image, selection,
                                outputFile);
                            if (found) {
                                JDialog window = new JDialog();
                                Container windowContent = window.getContentPane();
                                BufferedImage newImage = ImageIO.read(
                                    outputFile);
                                JLabel label = new JLabel(new ImageIcon(
                                    newImage));
                                JScrollPane pane = new JScrollPane(label);
                                windowContent.add(pane, BorderLayout.CENTER);
                                window.setSize(300, 300);
                                window
                                    .show();
                            }
                            else {
                                System.err.println("Error saving");
                            }
                        }
                    }
                    else {
                        System.err.println("Bad filename");
                    }
                }
                catch (MalformedURLException mur) {
                    System.err.println("Bad filename");
                }
                catch (IOException ioe) {
                    System.err.println("Error reading file");
                }
            }
        });
        contentPane.add(outputPanel, BorderLayout.SOUTH);
    }    public static void main(String args[]) {
        JFrame frame = new Converting();
        frame.pack();
        frame.show();
    }
}

Answer 2

dreamno,你好，我看了你的程序，给了我一些启发，但是执行你的程序后，总是显示“Invalid input file format”，我选择的是tif格式的图片文件，要转换成jpg的格式，我选择bmp的都不行，请问为什么，

Answer 3

public static boolean convert(String source,String target){
        try {
            RenderedOp rop = JAI.create("fileload", source);
            OutputStream outStream = new FileOutputStream(target);
            BMPEncodeParam param = new BMPEncodeParam();
            ImageEncoder imageEncoder = ImageCodec.createImageEncoder("BMP",
                outStream,
                param);
            imageEncoder.encode(rop);
            outStream.close();
        }
        catch(Exception ex){
            return false;
        }
        return true;
    }

Answer 4

需要jai_codec.jar,jai_core.jar这两个包。
可以在：
http://java.sun.com/products/java-media/jai/downloads/download-iio.html
下在到.如果不行的话。你给我留个
mail我给你发过去。