利用独立的servlet在页面显示图片

hank

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Servlet Java Apache Web SUN

web页面上的图片显示可以指定了一个url, 直接访问后台的一个servlet. 在后台数据库可以专门建一个图片库. 以下是一个简单的示例.在这里采用了imageJ-v1.37项目(网址: http://rsb.info.nih.gov/ij/ ) 进行图片处理.

1, ImageViewServlet

java 代码

package com.hank.web.servlet;
import java.io.IOException;
import java.io.OutputStream;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.springframework.context.ApplicationContext;
import org.springframework.web.context.support.WebApplicationContextUtils;
import com.hank.model.ConAttachs;
import com.hank.service.ConAttachsManager;
import com.hank.util.ImageUtil;
/**
* @author hank
* @date 2007-9-12 03:49:57
* @version
*/
public class ImageViewServlet extends HttpServlet {
private static final long serialVersionUID = 714920135153152003L;
protected final transient Log log = LogFactory.getLog(getClass());
@Override
protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
execute(request, response);
}
@Override
protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
execute(request, response);
}
public void execute(HttpServletRequest request, HttpServletResponse response)
throws IOException, ServletException {
String[] infos = request.getPathInfo().split("/");
String name=infos[1];
String id=infos[2].substring(0, infos[2].lastIndexOf('.'));
OutputStream out = response.getOutputStream();
ApplicationContext ctx =
WebApplicationContextUtils.getWebApplicationContext(getServletContext());
if (name.equals("conAttach")){
ConAttachsManager mgr = (ConAttachsManager)ctx.getBean("conAttachsManager");
ConAttachs conAttachs = mgr.getConAttachsByContextId(id);
if(conAttachs.getFType().intValue()==1){
return;
}
byte[] images = conAttachs.getContextFile();
try {
response.setContentType(conAttachs.getFhttpContent());//设置contentType
ImageUtil.outLogo(images,out,200,100);//显示200*100的缩略图
response.getOutputStream().flush();
} catch (Exception e) {
e.printStackTrace();
}finally{
if(out!=null){
out.close();
}
}
}else if(){
... ...
}
}
}

2, ImageUtil

java 代码

package com.hank.util;
import ij.ImagePlus;
import ij.io.Opener;
import ij.process.Blitter;
import ij.process.ImageProcessor;
import java.awt.Graphics;
import java.awt.Image;
import java.awt.image.BufferedImage;
import java.io.BufferedInputStream;
import java.io.BufferedOutputStream;
import java.io.ByteArrayInputStream;
import java.io.ByteArrayOutputStream;
import java.io.File;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.OutputStream;
import java.io.PrintWriter;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import com.sun.image.codec.jpeg.ImageFormatException;
import com.sun.image.codec.jpeg.JPEGCodec;
import com.sun.image.codec.jpeg.JPEGImageEncoder;
/**
* @author hank
* @date 2007-9-12 03:14:21
* @version
*/
public class ImageUtil {
protected final transient Log log = LogFactory.getLog(getClass());
public static void outLogo(byte[] source,OutputStream out,int dwidth,int dheight) throws Exception{
BufferedInputStream stream = new BufferedInputStream((new ByteArrayInputStream(source)),8092);//控制流速
Image src = javax.imageio.ImageIO.read(stream);
int width=src.getWidth(null);
int height=src.getHeight(null);
int towidth,toheight;
if (width>dwidth || height>dheight){
if (((float)width/dwidth)>=((float)height/dheight)){
towidth = dwidth;
toheight = (height*dwidth)/width;
}else{
toheight = dheight;
towidth = (width* dheight)/height;
}
}else{
towidth= width;
toheight=height;
}
BufferedImage tag = new BufferedImage(towidth,toheight,BufferedImage.TYPE_INT_RGB);
tag.getGraphics().drawImage(src,0,0,towidth,toheight,null);
JPEGImageEncoder encoder = JPEGCodec.createJPEGEncoder(out);
encoder.encode(tag);
}
}

3 ,在web.xml中配置 servlet

4 , 页面上直接使用img标签指定src即可

ij.jar (1 MB)
描述: imageJ包
下载次数: 270

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日期比较的两种方法 | " Ibatis读写CLOB数据 --Klyuan" 读后感

2007-09-19 02:01
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5 楼 javawxl 2008-04-30

学习！！！

4 楼 apchy 2008-04-26

写的不错，以前也实现过相似功能，但没不完善，收藏了

3 楼 liangguanhui 2008-04-08

这样生成的缩略图貌似很粗糙的。

2 楼 wy36928 2008-04-06

<div class='quote_title'>hank 写道</div><div class='quote_div'> web页面上的图片显示可以指定了一个url, 直接访问后台的一个servlet. 在后台数据库可以专门建一个图片库. 以下是一个简单的示例.在这里采用了imageJ-v1.37项目(网址: <a href='http://rsb.info.nih.gov/ij/'>http://rsb.info.nih.gov/ij/</a> ) 进行图片处理. 1, ImageViewServlet <div class='code_title'>java 代码</div><div class='dp-highlighter'><ol class='dp-j'><li class='alt'>package com.hank.web.servlet; </li><li> </li><li class='alt'>import java.io.IOException; </li><li/><li>testtest </li><li>import javax.servlet.http.HttpServletRequest; </li><li class='alt'>import javax.servlet.http.HttpServletResponse; </li><li> </li><li class='alt'>import org.apache.commons.logging.Log; </li><li>import org.apache.commons.logging.LogFactory; </li><li class='alt'>import org.springframework.context.ApplicationContext; </li><li>import org.springframework.web.context.support.WebApplicationContextUtils; </li><li class='alt'> </li><li>import com.hank.model.ConAttachs; </li><li class='alt'>import com.hank.service.ConAttachsManager; </li><li>import com.hank.util.ImageUtil; </li><li class='alt'> </li><li>/** </li><li class='alt'> * @author hank </li><li> * @date 2007-9-12 03:49:57 </li><li class='alt'> * @version </li><li> */ </li><li class='alt'>public class ImageViewServlet extends HttpServlet { </li><li> private static final long serialVersionUID = 714920135153152003L; </li><li class='alt'> protected final transient Log log = LogFactory.getLog(getClass()); </li><li> @Override </li><li class='alt'> protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { </li><li> execute(request, response); </li><li class='alt'> } </li><li> </li><li class='alt'> @Override </li><li> protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { </li><li class='alt'> execute(request, response); </li><li> } </li><li class='alt'> </li><li> public void execute(HttpServletRequest request, HttpServletResponse response) </li><li class='alt'> throws IOException, ServletException { </li><li> String[] infos = request.getPathInfo().split("/"); </li><li class='alt'> String name=infos[1]; </li><li> String id=infos[2].substring(0, infos[2].lastIndexOf('.')); </li><li class='alt'> </li><li> OutputStream out = response.getOutputStream(); </li><li class='alt'> </li><li> ApplicationContext ctx = </li><li class='alt'> WebApplicationContextUtils.getWebApplicationContext(getServletContext()); </li><li> </li><li class='alt'> if (name.equals("conAttach")){ </li><li> ConAttachsManager mgr = (ConAttachsManager)ctx.getBean("conAttachsManager"); </li><li class='alt'> ConAttachs conAttachs = mgr.getConAttachsByContextId(id); </li><li> </li><li class='alt'> if(conAttachs.getFType().intValue()==1){ </li><li> return; </li><li class='alt'> } </li><li> byte[] images = conAttachs.getContextFile(); </li><li class='alt'> try { </li><li> response.setContentType(conAttachs.getFhttpContent());//设置contentType </li><li class='alt'> ImageUtil.outLogo(images,out,200,100);//显示200*100的缩略图 </li><li> response.getOutputStream().flush(); </li><li class='alt'> } catch (Exception e) { </li><li> e.printStackTrace(); </li><li class='alt'> }finally{ </li><li> if(out!=null){ </li><li class='alt'> out.close(); </li><li> } </li><li class='alt'> } </li><li> }else if(){ </li><li class='alt'> ... ... </li><li> } </li><li class='alt'> } </li><li>} </li></ol></div> 2, ImageUtil<div class='code_title'>java 代码</div><div class='dp-highlighter'><ol class='dp-j'><li class='alt'>package com.hank.util; </li><li> </li><li class='alt'>import ij.ImagePlus; </li><li>import ij.io.Opener; </li><li class='alt'>import ij.process.Blitter; </li><li>import ij.process.ImageProcessor; </li><li class='alt'> </li><li>import java.awt.Graphics; </li><li class='alt'>import java.awt.Image; </li><li>import java.awt.image.BufferedImage; </li><li class='alt'>import java.io.BufferedInputStream; </li><li>import java.io.BufferedOutputStream; </li><li class='alt'>import java.io.ByteArrayInputStream; </li><li>import java.io.ByteArrayOutputStream; </li><li class='alt'>import java.io.File; </li><li>import java.io.FileOutputStream; </li><li class='alt'>import java.io.IOException; </li><li>import java.io.OutputStream; </li><li class='alt'>import java.io.PrintWriter; </li><li> </li><li class='alt'>import org.apache.commons.logging.Log; </li><li>import org.apache.commons.logging.LogFactory; </li><li class='alt'> </li><li>import com.sun.image.codec.jpeg.ImageFormatException; </li><li class='alt'>import com.sun.image.codec.jpeg.JPEGCodec; </li><li>import com.sun.image.codec.jpeg.JPEGImageEncoder; </li><li class='alt'> </li><li>/** </li><li class='alt'> * @author hank </li><li> * @date 2007-9-12 03:14:21 </li><li class='alt'> * @version </li><li> */ </li><li class='alt'>public class ImageUtil { </li><li> protected final transient Log log = LogFactory.getLog(getClass()); </li><li class='alt'> </li><li> public static void outLogo(byte[] source,OutputStream out,int dwidth,int dheight) throws Exception{ </li><li class='alt'> BufferedInputStream stream = new BufferedInputStream((new ByteArrayInputStream(source)),8092);//控制流速 </li><li> Image src = javax.imageio.ImageIO.read(stream); </li><li class='alt'> int width=src.getWidth(null); </li><li> int height=src.getHeight(null); </li><li class='alt'> int towidth,toheight; </li><li> if (width>dwidth || height>dheight){ </li><li class='alt'> if (((float)width/dwidth)>=((float)height/dheight)){ </li><li> towidth = dwidth; </li><li class='alt'> toheight = (height*dwidth)/width; </li><li> }else{ </li><li class='alt'> toheight = dheight; </li><li> towidth = (width* dheight)/height; </li><li class='alt'> } </li><li> }else{ </li><li class='alt'> towidth= width; </li><li> toheight=height; </li><li class='alt'> } </li><li> </li><li class='alt'> BufferedImage tag = new BufferedImage(towidth,toheight,BufferedImage.TYPE_INT_RGB); </li><li> tag.getGraphics().drawImage(src,0,0,towidth,toheight,null); </li><li class='alt'> JPEGImageEncoder encoder = JPEGCodec.createJPEGEncoder(out); </li><li> encoder.encode(tag); </li><li class='alt'> } </li><li>} </li></ol></div> 3 ,在web.xml中配置 servlet4 , 页面上直接使用img标签指定src即可 </div>

1 楼 yourgame 2008-04-05

import ij.ImagePlus;
import ij.io.Opener;
import ij.process.Blitter;
import ij.process.ImageProcessor;

貌似没有使用imageJ

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