servlet缩放图片

package util;

import java.awt.Image;
import java.awt.image.BufferedImage;
import java.io.File;
import java.io.FileOutputStream;

import javax.imageio.ImageIO;

import com.sun.image.codec.jpeg.JPEGCodec;
import com.sun.image.codec.jpeg.JPEGImageEncoder;

public class ScaleImage {
	private int width;

	private int height;

	private int scaleWidth;

	double support = (double) 3.0;

	double PI = (double) 3.14159265358978;

	double[] contrib;

	double[] normContrib;

	double[] tmpContrib;

	int startContrib, stopContrib;

	int nDots;

	int nHalfDots;
	
	
	public void suoImage(File file2,String savaurl) throws Exception
	{
		
		java.io.File file = file2;
		
		Image src = javax.imageio.ImageIO.read(file); 

		float tagsize=160;

		int old_w=src.getWidth(null); 

		int old_h=src.getHeight(null);

		int new_w=0;

		int new_h=0; 

		int tempsize;

		float tempdouble;

		if(old_w>old_h){

		tempdouble=old_w/tagsize;

		}else{

		tempdouble=old_h/tagsize;

		}

		new_w=Math.round(old_w/tempdouble);

		new_h=Math.round(old_h/tempdouble);//计算新图长宽

		BufferedImage tag = new BufferedImage(new_w,new_h,BufferedImage.TYPE_INT_RGB);

		tag.getGraphics().drawImage(src,0,0,new_w,new_h,null); 

		FileOutputStream newimage=new FileOutputStream(savaurl); 

		JPEGImageEncoder encoder = JPEGCodec.createJPEGEncoder(newimage);

		encoder.encode(tag); 

		newimage.close(); 

		
	}
	

	// fromFileStr原图片地�?,saveToFileStr生成缩略图地�?,formatWideth生成图片宽度,formatHeight高度
	public void saveImageAsJpg(String fromFileStr, String saveToFileStr,
			int formatWideth, int formatHeight) throws Exception {
		BufferedImage srcImage;
		File saveFile = new File(saveToFileStr);
		File fromFile = new File(fromFileStr);
		srcImage = javax.imageio.ImageIO.read(fromFile); // construct image
		int imageWideth = srcImage.getWidth(null);
		int imageHeight = srcImage.getHeight(null);
		int changeToWideth = 0;
		int changeToHeight = 0;
		if (imageWideth > 0 && imageHeight > 0) {
			// flag=true;
			if (imageWideth / imageHeight >= formatWideth / formatHeight) {
				if (imageWideth > formatWideth) {
					changeToWideth = formatWideth;
					changeToHeight = (imageHeight * formatWideth) / imageWideth;
				} else {
					changeToWideth = imageWideth;
					changeToHeight = imageHeight;
				}
			} else {
				if (imageHeight > formatHeight) {
					changeToHeight = formatHeight;
					changeToWideth = (imageWideth * formatHeight) / imageHeight;
				} else {
					changeToWideth = imageWideth;
					changeToHeight = imageHeight;
				}
			}
		}

		srcImage = imageZoomOut(srcImage, changeToWideth, changeToHeight);
		ImageIO.write(srcImage, "JPEG", saveFile);
	}

	public BufferedImage imageZoomOut(BufferedImage srcBufferImage, int w, int h) {
		width = srcBufferImage.getWidth();
		height = srcBufferImage.getHeight();
		scaleWidth = w;

		if (DetermineResultSize(w, h) == 1) {
			return srcBufferImage;
		}
		CalContrib();
		BufferedImage pbOut = HorizontalFiltering(srcBufferImage, w);
		BufferedImage pbFinalOut = VerticalFiltering(pbOut, h);
		return pbFinalOut;
	}

	// 决定图片尺寸
	private int DetermineResultSize(int w, int h) {
		double scaleH, scaleV;
		scaleH = (double) w / (double) width;
		scaleV = (double) h / (double) height;
		// �?要判断一下scaleH，scaleV，不做放大操�?
		if (scaleH >= 1.0 && scaleV >= 1.0) {
			return 1;
		}
		return 0;

	} // end of DetermineResultSize()

	private double Lanczos(int i, int inWidth, int outWidth, double Support) {
		double x;

		x = (double) i * (double) outWidth / (double) inWidth;

		return Math.sin(x * PI) / (x * PI) * Math.sin(x * PI / Support)
				/ (x * PI / Support);

	}

	private void CalContrib() {
		nHalfDots = (int) ((double) width * support / (double) scaleWidth);
		nDots = nHalfDots * 2 + 1;
		try {
			contrib = new double[nDots];
			normContrib = new double[nDots];
			tmpContrib = new double[nDots];
		} catch (Exception e) {
			System.out.println("init   contrib,normContrib,tmpContrib" + e);
		}

		int center = nHalfDots;
		contrib[center] = 1.0;

		double weight = 0.0;
		int i = 0;
		for (i = 1; i <= center; i++) {
			contrib[center + i] = Lanczos(i, width, scaleWidth, support);
			weight += contrib[center + i];
		}

		for (i = center - 1; i >= 0; i--) {
			contrib[i] = contrib[center * 2 - i];
		}

		weight = weight * 2 + 1.0;

		for (i = 0; i <= center; i++) {
			normContrib[i] = contrib[i] / weight;
		}

		for (i = center + 1; i < nDots; i++) {
			normContrib[i] = normContrib[center * 2 - i];
		}
	} // end of CalContrib()

	// 处理边缘
	private void CalTempContrib(int start, int stop) {
		double weight = 0;

		int i = 0;
		for (i = start; i <= stop; i++) {
			weight += contrib[i];
		}

		for (i = start; i <= stop; i++) {
			tmpContrib[i] = contrib[i] / weight;
		}

	} // end of CalTempContrib()

	private int GetRedValue(int rgbValue) {
		int temp = rgbValue & 0x00ff0000;
		return temp >> 16;
	}

	private int GetGreenValue(int rgbValue) {
		int temp = rgbValue & 0x0000ff00;
		return temp >> 8;
	}

	private int GetBlueValue(int rgbValue) {
		return rgbValue & 0x000000ff;
	}

	private int ComRGB(int redValue, int greenValue, int blueValue) {

		return (redValue << 16) + (greenValue << 8) + blueValue;
	}

	// 行水平滤�?
	private int HorizontalFilter(BufferedImage bufImg, int startX, int stopX,
			int start, int stop, int y, double[] pContrib) {
		double valueRed = 0.0;
		double valueGreen = 0.0;
		double valueBlue = 0.0;
		int valueRGB = 0;
		int i, j;

		for (i = startX, j = start; i <= stopX; i++, j++) {
			valueRGB = bufImg.getRGB(i, y);

			valueRed += GetRedValue(valueRGB) * pContrib[j];
			valueGreen += GetGreenValue(valueRGB) * pContrib[j];
			valueBlue += GetBlueValue(valueRGB) * pContrib[j];
		}

		valueRGB = ComRGB(Clip((int) valueRed), Clip((int) valueGreen),
				Clip((int) valueBlue));
		return valueRGB;

	} // end of HorizontalFilter()

	// 图片水平滤波
	private BufferedImage HorizontalFiltering(BufferedImage bufImage, int iOutW) {
		int dwInW = bufImage.getWidth();
		int dwInH = bufImage.getHeight();
		int value = 0;
		BufferedImage pbOut = new BufferedImage(iOutW, dwInH,
				BufferedImage.TYPE_INT_RGB);

		for (int x = 0; x < iOutW; x++) {

			int startX;
			int start;
			int X = (int) (((double) x) * ((double) dwInW) / ((double) iOutW) + 0.5);
			int y = 0;

			startX = X - nHalfDots;
			if (startX < 0) {
				startX = 0;
				start = nHalfDots - X;
			} else {
				start = 0;
			}

			int stop;
			int stopX = X + nHalfDots;
			if (stopX > (dwInW - 1)) {
				stopX = dwInW - 1;
				stop = nHalfDots + (dwInW - 1 - X);
			} else {
				stop = nHalfDots * 2;
			}

			if (start > 0 || stop < nDots - 1) {
				CalTempContrib(start, stop);
				for (y = 0; y < dwInH; y++) {
					value = HorizontalFilter(bufImage, startX, stopX, start,
							stop, y, tmpContrib);
					pbOut.setRGB(x, y, value);
				}
			} else {
				for (y = 0; y < dwInH; y++) {
					value = HorizontalFilter(bufImage, startX, stopX, start,
							stop, y, normContrib);
					pbOut.setRGB(x, y, value);
				}
			}
		}

		return pbOut;

	} // end of HorizontalFiltering()

	private int VerticalFilter(BufferedImage pbInImage, int startY, int stopY,
			int start, int stop, int x, double[] pContrib) {
		double valueRed = 0.0;
		double valueGreen = 0.0;
		double valueBlue = 0.0;
		int valueRGB = 0;
		int i, j;

		for (i = startY, j = start; i <= stopY; i++, j++) {
			valueRGB = pbInImage.getRGB(x, i);

			valueRed += GetRedValue(valueRGB) * pContrib[j];
			valueGreen += GetGreenValue(valueRGB) * pContrib[j];
			valueBlue += GetBlueValue(valueRGB) * pContrib[j];

		}

		valueRGB = ComRGB(Clip((int) valueRed), Clip((int) valueGreen),
				Clip((int) valueBlue));

		return valueRGB;

	} // end of VerticalFilter()

	private BufferedImage VerticalFiltering(BufferedImage pbImage, int iOutH) {
		int iW = pbImage.getWidth();
		int iH = pbImage.getHeight();
		int value = 0;
		BufferedImage pbOut = new BufferedImage(iW, iOutH,
				BufferedImage.TYPE_INT_RGB);

		for (int y = 0; y < iOutH; y++) {

			int startY;
			int start;
			int Y = (int) (((double) y) * ((double) iH) / ((double) iOutH) + 0.5);

			startY = Y - nHalfDots;
			if (startY < 0) {
				startY = 0;
				start = nHalfDots - Y;
			} else {
				start = 0;
			}

			int stop;
			int stopY = Y + nHalfDots;
			if (stopY > (int) (iH - 1)) {
				stopY = iH - 1;
				stop = nHalfDots + (iH - 1 - Y);
			} else {
				stop = nHalfDots * 2;
			}

			if (start > 0 || stop < nDots - 1) {
				CalTempContrib(start, stop);
				for (int x = 0; x < iW; x++) {
					value = VerticalFilter(pbImage, startY, stopY, start, stop,
							x, tmpContrib);
					pbOut.setRGB(x, y, value);
				}
			} else {
				for (int x = 0; x < iW; x++) {
					value = VerticalFilter(pbImage, startY, stopY, start, stop,
							x, normContrib);
					pbOut.setRGB(x, y, value);
				}
			}

		}

		return pbOut;

	} // end of VerticalFiltering()

	int Clip(int x) {
		if (x < 0)
			return 0;
		if (x > 255)
			return 255;
		return x;
	}

}

package servlet;

import java.io.File;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.util.List;

import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import org.apache.commons.fileupload.FileItem;
import org.apache.commons.fileupload.disk.DiskFileItemFactory;
import org.apache.commons.fileupload.servlet.ServletFileUpload;

import util.ScaleImage;

public class FileUpload extends HttpServlet {
	private static int formatWideth = 200;// 生成缩略图的宽
	private static int formatHeight = 200;// 生成缩略图的高

	public void doPost(HttpServletRequest request, HttpServletResponse response)
			throws ServletException, IOException {
		//request.setCharacterEncoding("utf-8"); // 设置编码
		response.setContentType("text/html; charset=utf-8");
		response.setCharacterEncoding("utf-8");// 设置编码

		// 获得磁盘文件条目工厂
		DiskFileItemFactory factory = new DiskFileItemFactory();
		// 获取文件需要上传到的路径
		String path = request.getRealPath("/upload");

		// 如果没以下两行设置的话，上传大的 文件 会占用 很多内存，
		// 设置暂时存放的 存储室 , 这个存储室，可以和 最终存储文件 的目录不同
		/**
		 * 原理 它是先存到 暂时存储室，然后在真正写到 对应目录的硬盘上， 按理来说 当上传一个文件时，其实是上传了两份，第一个是以 .tem
		 * 格式的 然后再将其真正写到 对应目录的硬盘上
		 */
		factory.setRepository(new File(path));
		// 设置 缓存的大小，当上传文件的容量超过该缓存时，直接放到 暂时存储室
		factory.setSizeThreshold(1024 * 1024);

		// 高水平的API文件上传处理
		ServletFileUpload upload = new ServletFileUpload(factory);

		try {
			// 可以上传多个文件
			List<FileItem> list = (List<FileItem>) upload.parseRequest(request);

			for (FileItem item : list) {
				// 获取表单的属性名字
				String name = item.getFieldName();

				// 如果获取的 表单信息是普通的 文本 信息
				if (item.isFormField()) {
					// 获取用户具体输入的字符串 
					String value = item.getString();
					
					value = new String(value.getBytes("ISO-8859-1"),"utf-8");
					
					request.setAttribute(name, value);
				}
				// 对传入的非 简单的字符串进行处理 ，比如说二进制的 图片，电影这些
				else {
					// 获取路径名
					String value = item.getName();
					// 索引到最后一个反斜杠
					int start = value.lastIndexOf("\\");
					// 截取 上传文件的 字符串名字，加1是 去掉反斜杠，
					String filename = value.substring(start + 1);

					request.setAttribute(name, filename);

					OutputStream out = new FileOutputStream(new File(path, filename));

					InputStream in = item.getInputStream();

					int length = 0;
					byte[] buf = new byte[1024];

					System.out.println("获取上传文件的总共的容量：" + item.getSize());

					// in.read(buf) 每次读到的数据存放在 buf 数组中
					while ((length = in.read(buf)) != -1) {
						// 在 buf 数组中 取出数据 写到 （输出流）磁盘上
						out.write(buf, 0, length);

					}

					in.close();
					out.close();

					ScaleImage si = new ScaleImage();
					//String filenameNew = filename.substring(0,filename.lastIndexOf("."));//缩略图名
					//String ext = filename.substring(filename.lastIndexOf("."));          //缩略图扩展名
					//si.saveImageAsJpg(path+"\\"+filename, path+"\\small\\"+filenameNew+ext, formatWideth, formatHeight);
					si.saveImageAsJpg(path+"\\"+filename, path+"\\small\\"+filename, formatWideth, formatHeight);
					request.setAttribute("smallName", filename);

				}
			}

		} catch (Exception e) {
			e.printStackTrace();
		}
		request.getRequestDispatcher("filedemo.jsp").forward(request, response);
	}

	public void doGet(HttpServletRequest request, HttpServletResponse response)
			throws ServletException, IOException {
		doPost(request, response);
	}

}

index.jsp

<%@ page language="java" import="java.util.*" contentType="text/html; charset=utf-8"%>
<%
String path = request.getContextPath();
String basePath = request.getScheme()+"://"+request.getServerName()+":"+request.getServerPort()+path+"/";
%>

<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
  <head>
    <base href="<%=basePath%>">
    <title>My JSP 'fileupload.jsp' starting page</title>
	<meta http-equiv="pragma" content="no-cache">
	<meta http-equiv="cache-control" content="no-cache">
	<meta http-equiv="expires" content="0">    
	<meta http-equiv="keywords" content="keyword1,keyword2,keyword3">
	<meta http-equiv="description" content="This is my page">
	<!--
	<link rel="stylesheet" type="text/css" href="styles.css">
	-->
  </head>
  <body>
     <form action="FileUpload" enctype="multipart/form-data" method="post" >
	               用户名：<input type="text" name="usename"> <br/>
	               上传文件：<input type="file" name="file1"><br/>
	    <!-- 
	              上传文件： <input type="file" name="file2"><br/>
	    -->
        <input type="submit" value="提交"/>
     </form>
  </body>
</html>

filedemo.jsp

<%@ page language="java" import="java.util.*" pageEncoding="UTF-8"%>
<%
String path = request.getContextPath();
String basePath = request.getScheme()+"://"+request.getServerName()+":"+request.getServerPort()+path+"/";
%>

<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
  <head>
    <base href="<%=basePath%>">
    
    <title>My JSP 'filedemo.jsp' starting page</title>
    
	<meta http-equiv="pragma" content="no-cache">
	<meta http-equiv="cache-control" content="no-cache">
	<meta http-equiv="expires" content="0">    
	<meta http-equiv="keywords" content="keyword1,keyword2,keyword3">
	<meta http-equiv="description" content="This is my page">
	<!--
	<link rel="stylesheet" type="text/css" href="styles.css">
	-->

  </head>
  
  <body>
    
    用户名：${requestScope.usename } <br/>
    文件：${requestScope.file1 }<br/>
    ${requestScope.file2 }<br/>
    <!-- 把上传的图片显示出来 -->
    <img alt="go" src="upload/small/<%=(String)request.getAttribute("file1")%> " />
    <br><br><br><br><br>
    <img alt="go" src="upload/<%=(String)request.getAttribute("file1")%> " />
    
  </body>
</html>

web.xml

<?xml version="1.0" encoding="UTF-8"?>
<web-app version="2.5" xmlns="http://java.sun.com/xml/ns/javaee"
	xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
	xsi:schemaLocation="http://java.sun.com/xml/ns/javaee 
	http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd">

	
	<servlet>
		<servlet-name>FileUpload</servlet-name>
		<servlet-class>servlet.FileUpload</servlet-class>
	</servlet>
 
	<servlet-mapping>
		<servlet-name>FileUpload</servlet-name>
		<url-pattern>/FileUpload</url-pattern>
	</servlet-mapping>

	<welcome-file-list>
		<welcome-file>index.jsp</welcome-file>
	</welcome-file-list>
</web-app>

源码http://download.csdn.net/detail/djun100/5994569