package test; 
import java.io.*; 
import java.util.Date; 
import java.awt.*; 
import java.awt.image.*; 
import javax.imageio.ImageIO; 
import com.sun.image.codec.jpeg.*; 
/** 
 * 图片压缩处理 
 * @author 崔素强 
 */ 
public class ImgCompress { 
  private Image img; 
  private int width; 
  private int height; 
  @SuppressWarnings("deprecation") 
  public static void main(String[] args) throws Exception { 
    System.out.println("开始：" + new Date().toLocaleString()); 
    ImgCompress imgCom = new ImgCompress("C:\\temp\\pic123.jpg"); 
    imgCom.resizeFix(400, 400); 
    System.out.println("结束：" + new Date().toLocaleString()); 
  } 
  /** 
   * 构造函数 
   */ 
  public ImgCompress(String fileName) throws IOException { 
    File file = new File(fileName);// 读入文件 
    img = ImageIO.read(file);   // 构造Image对象 
    width = img.getWidth(null);  // 得到源图宽 
    height = img.getHeight(null); // 得到源图长 
  } 
  /** 
   * 按照宽度还是高度进行压缩 
   * @param w int 最大宽度 
   * @param h int 最大高度 
   */ 
  public void resizeFix(int w, int h) throws IOException { 
    if (width / height > w / h) { 
      resizeByWidth(w); 
    } else { 
      resizeByHeight(h); 
    } 
  } 
  /** 
   * 以宽度为基准，等比例放缩图片 
   * @param w int 新宽度 
   */ 
  public void resizeByWidth(int w) throws IOException { 
    int h = (int) (height * w / width); 
    resize(w, h); 
  } 
  /** 
   * 以高度为基准，等比例缩放图片 
   * @param h int 新高度 
   */ 
  public void resizeByHeight(int h) throws IOException { 
    int w = (int) (width * h / height); 
    resize(w, h); 
  } 
  /** 
   * 强制压缩/放大图片到固定的大小 
   * @param w int 新宽度 
   * @param h int 新高度 
   */ 
  public void resize(int w, int h) throws IOException { 
    // SCALE_SMOOTH 的缩略算法 生成缩略图片的平滑度的 优先级比速度高 生成的图片质量比较好 但速度慢 
    BufferedImage image = new BufferedImage(w, h,BufferedImage.TYPE_INT_RGB );  
    image.getGraphics().drawImage(img, 0, 0, w, h, null); // 绘制缩小后的图 
    File destFile = new File("C:\\temp\\456.jpg"); 
    FileOutputStream out = new FileOutputStream(destFile); // 输出到文件流 
    // 可以正常实现bmp、png、gif转jpg 
    JPEGImageEncoder encoder = JPEGCodec.createJPEGEncoder(out); 
    encoder.encode(image); // JPEG编码 
    out.close(); 
  } 
} 

开始：2014-4-14 16:25:11 
Exception in thread "main" java.lang.OutOfMemoryError: Java heap space 
  at java.awt.image.DataBufferByte.(DataBufferByte.java:58) 
  at java.awt.image.ComponentSampleModel.createDataBuffer(ComponentSampleModel.java:397) 
  at java.awt.image.Raster.createWritableRaster(Raster.java:938) 
  at javax.imageio.ImageTypeSpecifier.createBufferedImage(ImageTypeSpecifier.java:1169) 
  at javax.imageio.ImageReader.getDestination(ImageReader.java:2879) 
  at com.sun.imageio.plugins.jpeg.JPEGImageReader.readInternal(JPEGImageReader.java:943) 
  at com.sun.imageio.plugins.jpeg.JPEGImageReader.read(JPEGImageReader.java:915) 
  at javax.imageio.ImageIO.read(ImageIO.java:1422) 
  at javax.imageio.ImageIO.read(ImageIO.java:1282) 
  at test.ImgCompress.(ImgCompress.java:31) 
  at test.ImgCompress.main(ImgCompress.java:21)