Servlet从本地文件中读取图片,并显示在页面中

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api
import 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 implements
javax.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>

这样图片便显示在htm上了

 转载于:http://tntxia.iteye.com/blog/826193
 

JSP中显示图片的主要代码就是:

  <img src="http://localhost:8080/imgShow/ImageShowServlet" />

  其中"imgShow"是项目名称, "ImageShowServlet"是url-pattern.

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