本java类能将jpg图片文件

package com.binghe.pub.util;

import java.io.*;
import com.sun.image.codec.jpeg.*;
import java.awt.image.*;
import java.awt.*;
import java.applet.*;

//缩略图类，
//本java类能将jpg图片文件，进行等比或非等比的大小转换。
//具体使用方法
//s_pic(大图片路径,生成小图片路径,大图片文件名,生成小图片文名,生成小图片宽度,生成小图片高度,是否等比缩放(默认为true))
public class SmallPic {
 String InputDir; // 输入图路径

 String OutputDir; // 输出图路径

 String InputFileName; // 输入图文件名

 String OutputFileName; // 输出图文件名

 int OutputWidth = 80; // 默认输出图片宽

 int OutputHeight = 80; // 默认输出图片高

 int rate = 0;

 boolean proportion = true; // 是否等比缩放标记(默认为等比缩放)

 public SmallPic() {
  // 初始化变量
  InputDir = "";
  OutputDir = "";
  InputFileName = "";
  OutputFileName = "";
  OutputWidth = 80;
  OutputHeight = 80;
  rate = 0;
 }

 public void setInputDir(String InputDir) {
  this.InputDir = InputDir;
 }

 public void setOutputDir(String OutputDir) {
  this.OutputDir = OutputDir;
 }

 public void setInputFileName(String InputFileName) {
  this.InputFileName = InputFileName;
 }

 public void setOutputFileName(String OutputFileName) {
  this.OutputFileName = OutputFileName;
 }

 public void setOutputWidth(int OutputWidth) {
  this.OutputWidth = OutputWidth;
 }

 public void setOutputHeight(int OutputHeight) {
  this.OutputHeight = OutputHeight;
 }

 public void setW_H(int width, int height) {
  this.OutputWidth = width;
  this.OutputHeight = height;
 }

 public String s_pic() {
  // 建立输出文件对象
  File file = new File(OutputDir + OutputFileName);
  FileOutputStream tempout = null;
  try {
   tempout = new FileOutputStream(file);
  } catch (Exception ex) {
   System.out.println(ex.toString());
  }
  Image img = null;
  Toolkit tk = Toolkit.getDefaultToolkit();
  Applet app = new Applet();
  MediaTracker mt = new MediaTracker(app);
  try {
   img = tk.getImage(InputDir + InputFileName);
   mt.addImage(img, 0);
   mt.waitForID(0);
  } catch (Exception e) {
   e.printStackTrace();
  }

  if (img.getWidth(null) == -1) {
   System.out.println(" can’t read,retry!" + "<BR>");
   return "no";
  } else {
   int new_w;
   int new_h;
   if (this.proportion == true) // 判断是否是等比缩放.
   {
    // 为等比缩放计算输出的图片宽度及高度
    double rate1 = ((double) img.getWidth(null))
      / (double) OutputWidth + 0.1;
    double rate2 = ((double) img.getHeight(null))
      / (double) OutputHeight + 0.1;
    double rate = rate1 > rate2 ? rate1 : rate2;
    new_w = (int) (((double) img.getWidth(null)) / rate);
    new_h = (int) (((double) img.getHeight(null)) / rate);
   } else {
    new_w = OutputWidth; // 输出的图片宽度
    new_h = OutputHeight; // 输出的图片高度
   }
   BufferedImage buffImg = new BufferedImage(new_w, new_h,
     BufferedImage.TYPE_INT_RGB);

   Graphics g = buffImg.createGraphics();

   g.setColor(Color.white);
   g.fillRect(0, 0, new_w, new_h);

   g.drawImage(img, 0, 0, new_w, new_h, null);
   g.dispose();

   JPEGImageEncoder encoder = JPEGCodec.createJPEGEncoder(tempout);
   try {
    encoder.encode(buffImg);
    tempout.close();
   } catch (IOException ex) {
    System.out.println(ex.toString());
   }
  }
  return "ok";
 }

 public String s_pic(String InputDir, String OutputDir,
   String InputFileName, String OutputFileName) {
  // 输入图路径
  this.InputDir = InputDir;
  // 输出图路径
  this.OutputDir = OutputDir;
  // 输入图文件名
  this.InputFileName = InputFileName;
  // 输出图文件名
  this.OutputFileName = OutputFileName;
  return s_pic();
 }

 public String s_pic(String InputDir, String OutputDir,
   String InputFileName, String OutputFileName, int width, int height,
   boolean gp) {
  // 输入图路径
  this.InputDir = InputDir;
  // 输出图路径
  this.OutputDir = OutputDir;
  // 输入图文件名
  this.InputFileName = InputFileName;
  // 输出图文件名
  this.OutputFileName = OutputFileName;
  // 设置图片长宽
  setW_H(width, height);
  // 是否是等比缩放 标记
  this.proportion = gp;
  return s_pic();
 }

// public static void main(String[] a) {
//  // s_pic(大图片路径,生成小图片路径,大图片文件名,生成小图片文名,生成小图片宽度,生成小图片高度)
//  Small_pic mypic = new Small_pic();
//  System.out.println(mypic.s_pic(
//    "E:\\JAVA\\J2EEDatum\\王亮jsp资料\\缩图例子\\personal\\",
//    "E:\\JAVA\\J2EEDatum\\酒剑仙jsp资料\\缩图例子\\personal\\", "1.jpg",
//    "new1.jpg", 80, 80, true));
// }

}