ImageIO类的使用

如何从文件或URL中读取图像?

1.从本地文本读取图片 

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

 2.从网络上获取图片

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

如何写一个图像文件- Java ImagelO? 

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("https://tse3-mm.cn.bing.net/th/id/OIP-C.g9UbVfyVZX-SfD09JcYr5QHaEK?rs=1&pid=ImgDetMain");
            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:

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("https://tse3-mm.cn.bing.net/th/id/OIP-C.g9UbVfyVZX-SfD09JcYr5QHaEK?rs=1&pid=ImgDetMain");
            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");
    }
}

如何在Java中加载和编写图像?

加载图片:

BufferedImage originalImage = ImageIO.read(new File("D:\\img\\0a3b3288-3446-4420-bbff-f263d0c02d8e.jpg"));

 写入图片：

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

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

        } catch (IOException e) {
            System.out.println(e.getMessage());
        }

    }

}