Servlet实现图片展示和下载的代码

  
import java.io.File;  
  
public class ShowImage extends HttpServlet {  
  
    /** 
     * Constructor of the object. 
     */  
    public ShowImage() {  
        super();  
    }  
  
    /** 
     * Destruction of the servlet. 
 
     */  
    public void destroy() {  
        super.destroy(); // Just puts "destroy" string in log  
        // Put your code here  
    }  
  
    public void doGet(HttpServletRequest request, HttpServletResponse response)  
            throws ServletException, IOException {  
  
//      showImage(request, response);  
        downlodeImage(request, response);  
    }  
  
    public void showImage(HttpServletRequest request,  
            HttpServletResponse response) throws ServletException, IOException {  
        // 读取方式  
        // response.setContentType("application/zip");  
        response.setContentType("image/jpeg");  
        // 获取图片绝对路径  
        String path = this.getServletContext().getRealPath("/");  
        File file = new File(path + "/images/WIN_20131027_214421.JPG");  
        // 创建文件输入流  
        FileInputStream is = new FileInputStream(file);  
        // 响应输出流  
        ServletOutputStream out = response.getOutputStream();  
        // 创建缓冲区  
        byte[] buffer = new byte[1024];  
        int len = 0;  
        while ((len = is.read(buffer)) != -1) {  
            out.write(buffer, 0, len);  
        }  
        is.close();  
        out.flush();  
        out.close();  
  
    }  
  
    public void downlodeImage(HttpServletRequest request,  
            HttpServletResponse response) throws ServletException, IOException {  
          
        // 获取图片绝对路径  
        String path = this.getServletContext().getRealPath("/");  
        File file = new File(path + "/images/WIN_20131027_214421.JPG");  
        //设置头信息,内容处理的方式,attachment以附件的形式打开,就是进行下载,并设置下载文件的命名  
        response.setHeader("Content-Disposition","attachment;filename="+file.getName());  
        // 创建文件输入流  
        FileInputStream is = new FileInputStream(file);  
        // 响应输出流  
        ServletOutputStream out = response.getOutputStream();  
        // 创建缓冲区  
        byte[] buffer = new byte[1024];  
        int len = 0;  
        while ((len = is.read(buffer)) != -1) {  
            out.write(buffer, 0, len);  
        }  
        is.close();  
        out.flush();  
        out.close();  
  
    }  
  
    public void doPost(HttpServletRequest request, HttpServletResponse response)  
            throws ServletException, IOException {  
  
        this.doGet(request, response);  
    }  
  
}