ImageIO类的使用

重点内容
(一) How to read an image from file or URL？

1. 从本地文本读取图片

File sourceimage = new File("c:\\mypic.jpg");Image image = ImageIO.read(sourceimage);

1. 从网络上获取图片

URL url = new URL("http://www.mkyong.com/image/mypic.jpg");Image image = ImageIO.read(url);

3.使用ImageIO读取图片实例

package ImageIO;import java.awt.Image;import java.io.IOException;import java.net.URL;import javax.imageio.ImageIO;import javax.swing.ImageIcon;import javax.swing.JFrame;import javax.swing.JLabel;public class ReadImage{    public static void main( String[] args )    {        Image image = null;        try {            URL url = new URL("http://img04.tooopen.com/images/20130805/tooopen_10473021.jpg");            image = ImageIO.read(url);        } catch (IOException e) {            e.printStackTrace();        }        JFrame frame = new JFrame();        frame.setSize(300, 300);        JLabel label = new JLabel(new ImageIcon(image));        frame.add(label);        frame.setVisible(true);    }}

结果：

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(二)How to write an image to file - Java ImageIO？

1.ImageIO可以从本地文件中读取图片和写入图片，也可以从网络上读取图片写入本地文件中。

2.演示ImageIO读取URL资源

package ImageIO;import java.awt.image.BufferedImage;import java.io.File;import java.io.IOException;import java.net.URL;import javax.imageio.ImageIO;public class WriteImage{    public static void main( String[] args )    {        BufferedImage image = null;        try {            URL url = new URL("http://p3.so.qhmsg.com/t014d3503dd2d67d728.jpg");            image = ImageIO.read(url);            //.jpg文件占空间最小            ImageIO.write(image, "jpg",new File("D:\\out.jpg"));            ImageIO.write(image, "gif",new File("D:\\out.gif"));            ImageIO.write(image, "png",new File("D:\\out.png"));        } catch (IOException e) {            e.printStackTrace();        }        System.out.println("成功写入D盘");    }}

3.How to load and write an image in Java?

加载图片：

BufferedImage originalImage = ImageIO.read(new File("c:\\image\\1.jpg"));

写入图片：

ImageIO.write(originalImage, "jpg", new File("c:\\image\\1.jpg"));

读写操作实例代码演示：

import java.awt.image.BufferedImage;import java.io.File;import java.io.IOException;import javax.imageio.ImageIO;public class ImageTest {    public static void main(String[] args) {        try {           //使用jpg格式，可以减少存储空间            BufferedImage originalImage = ImageIO.read(new File(                    "c:\\image\\1.jpg"));            ImageIO.write(originalImage, "jpg", new File(                    "c:\\image\\1.jpg"));        } catch (IOException e) {            System.out.println(e.getMessage());        }    }}