程序员网: 使用J2SE1.4新特性来获取图象资源

使用J2SE1.4新特性来获取图象资源

14:28

下面的这个例子示范怎样使用javax.imageio包来从一个文件、输入流或URL获取图象资源，同时也示范了如何来把Image显示到屏幕上. javax.imageio包默认支持GIF,PNG和JPEG格式的图片，这个例子只能工作在J2SE1.4或以上版本

 
    Image image = null;
    try {
        File file = new File("image.gif");
        image = ImageIO.read(file);
 
        InputStream is = new BufferedInputStream(
            new FileInputStream("image.gif"));
        image = ImageIO.read(is);
    
        URL url = new URL("http://hostname.com/image.gif");
        image = ImageIO.read(url);
    } catch (IOException e) {
    }
    
    JFrame frame = new JFrame();
    JLabel label = new JLabel(new ImageIcon(image));
    frame.getContentPane().add(label, BorderLayout.CENTER);
    frame.pack();
    frame.setVisible(true);

包javax.imageio默认可以读和写一个GIF,PNG和JPEG图片，你可以调用ImageIO.getReaderFormatNames() 和ImageIO.getWriterFormatNames()来列出全部可读和可写的图片格式

 
    String[] formatNames = ImageIO.getReaderFormatNames();
    formatNames = unique(formatNames);
    
    formatNames = ImageIO.getWriterFormatNames();
    formatNames = unique(formatNames);
    // png jpeg jpg
    

    formatNames = ImageIO.getReaderMIMETypes();
    formatNames = unique(formatNames);
    // image/jpeg image/png image/x-png image/gif
    
    formatNames = ImageIO.getWriterMIMETypes();
    formatNames = unique(formatNames);
    // image/jpeg image/png image/x-png
    

    public static String[] unique(String[] strings) {
        Set set = new HashSet();
        for (int i=0; i

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