Java縮略圖類

import java.io.*;

import java.awt.*;

import java.awt.image.*;

import com.sun.image.codec.jpeg.*;

/**

 *

 * <p>Title: Thumbnail</p>

 * <p>Description: Picture Thumbnail</p>

 * @author 54powerman

 * @version 1.0

 */

public class Thumbnail {

  private String srcFile;

  private String destFile;

  private int width;

  private int height;

  private Image img;

  public static void main(String[] args) throws Exception {

    Thumbnail thum = new Thumbnail("Winter.png");

    thum.resizeFix(500, 300);

  }

  /**

   * 構造函數

   * @param fileName String

   * @throws IOException

   */

  public Thumbnail(String fileName) throws IOException {

    File _file = new File(fileName); //讀入檔案

    this.srcFile = _file.getName();

    this.destFile = this.srcFile.substring(0, this.srcFile.lastIndexOf(".")) +

        "_s.jpg";

    img = javax.imageio.ImageIO.read(_file); //構造Image對象

    width = img.getWidth(null); //得到源圖寬

    height = img.getHeight(null); //得到源圖長

   * 強制壓縮/放大圖檔到固定的大小

   * @param w int 新寬度

   * @param h int 新高度

  public void resize(int w, int h) throws IOException {

    BufferedImage _image = new BufferedImage(w, h,

                                             BufferedImage.TYPE_INT_RGB);

    _image.getGraphics().drawImage(img, 0, 0, w, h, null); //繪制縮小後的圖

    FileOutputStream out = new FileOutputStream(destFile); //輸出到檔案流

    JPEGImageEncoder encoder = JPEGCodec.createJPEGEncoder(out);

    encoder.encode(_image); //近JPEG編碼

    out.close();

   * 按照固定的比例縮放圖檔

   * @param t double 比例

  public void resize(double t) throws IOException {

    int w = (int) (width * t);

    int h = (int) (height * t);

    resize(w, h);

   * 以寬度為基準，等比例放縮圖檔

  public void resizeByWidth(int w) throws IOException {

    int h = (int) (height * w / width);

   * 以高度為基準，等比例縮放圖檔

  public void resizeByHeight(int h) throws IOException {

    int w = (int) (width * h / height);

   * 按照最大高度限制，生成最大的等比例縮略圖

   * @param w int 最大寬度

   * @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);

   * 設定目标檔案名

   * setDestFile

   * @param fileName String 檔案名字元串

  public void setDestFile(String fileName) throws Exception {

    if (!fileName.endsWith(".jpg")) {

      throw new Exception("Dest File Must end with /".jpg/".");

    destFile = fileName;

   * 擷取目标檔案名

   * getDestFile

  public String getDestFile() {

    return destFile;

   * 擷取圖檔原始寬度

   * getSrcWidth

  public int getSrcWidth() {

    return width;

   * 擷取圖檔原始高度

   * getSrcHeight

  public int getSrcHeight() {

    return height;

}