java ImageIO处理

javax.imageio
使用 ImageIO 类的静态方法可以执行许多常见的图像 I/O 操作。 　　
此包包含一些基本类和接口，有的用来描述图像文件内容（包括元数据和缩略图）(IIOImage)；

有的用来控制图像读取过程（ImageReader、ImageReadParam）和控制图像写入过程（ImageWriter 和 ImageWriteParam）；

详细 java ImageIO处理图像的封装例子     http://www.gzhost.net/Artdetail-1609-649.html

package com.mapbar.graphics;import java.awt.Graphics;import java.awt.Image;import java.awt.Rectangle;import java.awt.image.BufferedImage;import java.io.File;import java.io.FileOutputStream;import java.io.IOException;import java.util.Arrays;import java.util.Iterator;import javax.imageio.ImageIO;import javax.imageio.ImageReadParam;import javax.imageio.ImageReader;import javax.imageio.metadata.IIOMetadata;import javax.imageio.stream.ImageInputStream;import com.sun.image.codec.jpeg.JPEGCodec;import com.sun.image.codec.jpeg.JPEGImageEncoder;/** *  * Class ImageIOTest.java *  * Description javax.imageio 操作 *  * Company mapbar *  * author Chenll E-mail: [e-mail] *  * Version 1.0 *  * Date 2012-7-23 上午11:16:17 */public class ImageIOTest {/** * Java Image I/O API 支持的读入，写出普通的格式，如果需要开发其它格式，还需要第三方插件，eg JIMI, JMagic */public void formatImageNames() {String[] imageFormats = ImageIO.getReaderFormatNames();// [jpg, BMP, bmp, JPG, wbmp, jpeg, png, PNG, JPEG, WBMP, GIF, gif]System.out.println(Arrays.asList(imageFormats));String[] imageFormats1 = ImageIO.getWriterFormatNames();// [BMP, bmp, jpg, JPG, wbmp, jpeg, png, PNG, JPEG, WBMP, GIF, gif]System.out.println(Arrays.asList(imageFormats1));}/** * Image I/O高级操作 ImageReader ImageWriter 通过ImageReader * 可以获取图片信息而不用把整张图片数据都读入内存。 *  * @throws IOException */public void imageReaderOp() throws IOException {Iterator<ImageReader> readers = ImageIO.getImageReadersByFormatName("JPG");ImageReader reader = readers.next();// 构造输入源File bigFile = new File("E:\\big.JPG");ImageInputStream iis = ImageIO.createImageInputStream(bigFile);// 输入源和ImageReader关联reader.setInput(iis, true);// 获取第一张图片的高度,试图解码文件的必要部分，去获取图片的宽度，而不用读取任何一个象素int imageIndex = 0;int width = reader.getWidth(imageIndex);}/** * 控制图片操作，ImageReadParam 可以让程序更好的控制内存，比如指定一个感兴趣的区域 *  * @throws IOException */public void imageReadParamOp() throws IOException {int imageIndex = 0;Iterator<ImageReader> readers = ImageIO.getImageReadersByFormatName("JPG");ImageReader reader = readers.next();File bigFile = new File("E:\\big.JPG");ImageInputStream iis = ImageIO.createImageInputStream(bigFile);reader.setInput(iis, true);ImageReadParam irp = reader.getDefaultReadParam();int halfWidth = reader.getWidth(imageIndex) / 2;int halfHeight = reader.getHeight(imageIndex) / 2;Rectangle rect = new Rectangle(0, 0, halfWidth, halfHeight);irp.setSourceRegion(rect);BufferedImage bi = reader.read(imageIndex, irp);ImageIO.write(bi, "JPG", new File("E:\\big_half.JPG"));}/** * 图片元信息 *  * @throws IOException */public void ImageMetadata() throws IOException {int imageIndex = 0;Iterator<ImageReader> readers = ImageIO.getImageReadersByFormatName("JPG");ImageReader reader = readers.next();File bigFile = new File("E:\\big.JPG");ImageInputStream iis = ImageIO.createImageInputStream(bigFile);reader.setInput(iis, true);IIOMetadata metadata = reader.getImageMetadata(imageIndex);}/** * 生成缩略图 *  * @throws IOException */public void generateSmall() throws IOException {File bigFile = new File("E:\\big.JPG");Image image = ImageIO.read(bigFile);int width = image.getWidth(null); // 3264int height = image.getHeight(null); // 2448BufferedImage buffi = new BufferedImage(width / 2, height / 2,BufferedImage.TYPE_INT_RGB);Graphics g = buffi.getGraphics();g.drawImage(image, 0, 0, width / 2, height / 2, null);g.dispose();ImageIO.write(buffi, "JPG", new File("E:\\small.JPG"));// width:1632 height:1224}public static void main(String[] args) throws IOException {ImageIOTest iot = new ImageIOTest();iot.generateSmall();iot.formatImageNames();iot.imageReaderOp();iot.imageReadParamOp();iot.ImageMetadata();}}