java 截取局部图片

package com.image;
 
import java.awt.Rectangle;
import java.awt.image.BufferedImage;
import java.io.*;
import java.util.Iterator;
import javax.imageio.ImageIO;
import javax.imageio.ImageReadParam;
import javax.imageio.ImageReader;
import javax.imageio.stream.ImageInputStream;
 
public class ImageUtils {
    public static void cutJPG(InputStream input, OutputStream out, int x,
            int y, int width, int height) throws IOException {
        ImageInputStream imageStream = null;
        try {
            Iterator readers = ImageIO.getImageReadersByFormatName("jpg");
            ImageReader reader = readers.next();
            imageStream = ImageIO.createImageInputStream(input);
            reader.setInput(imageStream, true);
            ImageReadParam param = reader.getDefaultReadParam();
            
            System.out.println(reader.getWidth(0));
            System.out.println(reader.getHeight(0));
            Rectangle rect = new Rectangle(x, y, width, height);
            param.setSourceRegion(rect);
            BufferedImage bi = reader.read(0, param);
            ImageIO.write(bi, "jpg", out);
        } finally {
            imageStream.close();
        }
    }
    
    
    public static void cutPNG(InputStream input, OutputStream out, int x,
            int y, int width, int height) throws IOException {
        ImageInputStream imageStream = null;
        try {
            Iterator readers = ImageIO.getImageReadersByFormatName("png");
            ImageReader reader = readers.next();
            imageStream = ImageIO.createImageInputStream(input);
            reader.setInput(imageStream, true);
            ImageReadParam param = reader.getDefaultReadParam();
            
            System.out.println(reader.getWidth(0));
            System.out.println(reader.getHeight(0));
            
            Rectangle rect = new Rectangle(x, y, width, height);
            param.setSourceRegion(rect);
            BufferedImage bi = reader.read(0, param);
            ImageIO.write(bi, "png", out);
        } finally {
            imageStream.close();
        }
    }
    
    public static void cutImage(InputStream input, OutputStream out, String type,int x,
            int y, int width, int height) throws IOException {
        ImageInputStream imageStream = null;
        try {
            String imageType=(null==type||"".equals(type))?"jpg":type;
            Iterator readers = ImageIO.getImageReadersByFormatName(imageType);
            ImageReader reader = readers.next();
            imageStream = ImageIO.createImageInputStream(input);
            reader.setInput(imageStream, true);
            ImageReadParam param = reader.getDefaultReadParam();
            Rectangle rect = new Rectangle(x, y, width, height);
            param.setSourceRegion(rect);
            BufferedImage bi = reader.read(0, param);
            ImageIO.write(bi, imageType, out);
        } finally {
            imageStream.close();
        }
    }
 
    
    public static void main(String[] args) throws Exception {
        ImageUtils.cutJPG(new FileInputStream("c:\\test.JPG"),
                  new FileOutputStream("c:\\test2.jpg"), 0,0,200,100);
        
        ImageUtils.cutPNG(new FileInputStream("c:\\1.png"),
                new FileOutputStream("c:\\test3.png"), 0,0,50,40);
    }
}