Servlet从本地文件中读取图片，并显示在页面中

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文章来源： http://tntxia.iteye.com/blog/826193

import java.io.IOException;import javax.servlet.ServletException;import javax.servlet.http.HttpServletRequest;import javax.servlet.http.HttpServletResponse;import java.io.*;import javax.servlet.*;import javax.servlet.http.*;import com.sun.image.codec.jpeg.*;//sun公司仅提供了jpg图片文件的编码apiimport javax.imageio.stream.*;import java.awt.*;import java.awt.image.BufferedImage;/** *  * 显示文件的Servlet * 负责从本地文件中读取图片， *  */public class ShowPic extends javax.servlet.http.HttpServlet implementsjavax.servlet.Servlet {private static final String GIF = "image/gif;charset=GB2312";// 设定输出的类型private static final String JPG = "image/jpeg;charset=GB2312";/* * (non-Java-doc) *  * @see javax.servlet.http.HttpServlet#HttpServlet() */public ShowPic() {super();}/* * (non-Java-doc) *  * @see javax.servlet.http.HttpServlet#doGet(HttpServletRequest request, *      HttpServletResponse response) */protected void doGet(HttpServletRequest request,HttpServletResponse response) throws ServletException, IOException {doPost(request, response);}/* * (non-Java-doc) *  * @see javax.servlet.http.HttpServlet#doPost(HttpServletRequest request, *      HttpServletResponse response) */protected void doPost(HttpServletRequest request,HttpServletResponse response) throws ServletException, IOException {String spec = request.getParameter("spec");// 输出图片的类型的标志String imagePath = "D:\\temp\\1.jpg";response.reset();OutputStream output = response.getOutputStream();// 得到输出流if (imagePath.toLowerCase().endsWith(".jpg"))// 使用编码处理文件流的情况：{response.setContentType(JPG);// 设定输出的类型// 得到图片的真实路径// 得到图片的文件流InputStream imageIn = new FileInputStream(new File(imagePath));// 得到输入的编码器，将文件流进行jpg格式编码JPEGImageDecoder decoder = JPEGCodec.createJPEGDecoder(imageIn);// 得到编码后的图片对象BufferedImage image = decoder.decodeAsBufferedImage();// 得到输出的编码器JPEGImageEncoder encoder = JPEGCodec.createJPEGEncoder(output);encoder.encode(image);// 对图片进行输出编码imageIn.close();// 关闭文件流}if (imagePath.toLowerCase().endsWith(".gif"))// 不使用编码处理文件流的情况：{response.setContentType(GIF);ServletContext context = getServletContext();// 得到背景对象InputStream imageIn = context.getResourceAsStream(imagePath);// 文件流BufferedInputStream bis = new BufferedInputStream(imageIn);// 输入缓冲流BufferedOutputStream bos = new BufferedOutputStream(output);// 输出缓冲流byte data[] = new byte[4096];// 缓冲字节数int size = 0;size = bis.read(data);while (size != -1) {bos.write(data, 0, size);size = bis.read(data);}bis.close();bos.flush();// 清空输出缓冲流bos.close();}output.close();}}

想要调用的话，你可以简单的映射一下servelt，我就将servet的名映射为

<servlet>  <servlet-name>ShowPic</servlet-name>  <display-name>ShowPic</display-name>  <description></description>  <servlet-class>  cn.ccb.zlgz.web.servlet.ShowPic</servlet-class>  </servlet>  <servlet-mapping>  <servlet-name>ShowPic</servlet-name>  <url-pattern>/ShowPic</url-pattern>  </servlet-mapping>

使用HTML调用：

<html><body><img src="ShowPic?spec=2"></a></body></html>

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