【jsp】读取WebRoot下的图像文件

package readPic;

import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;

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

public class ReadPic extends HttpServlet{

    /**
     *
     */
    private static final long serialVersionUID = 1L;

    public void doGet(HttpServletRequest req,HttpServletResponse resp)
    throws IOException,ServletException{
        resp.setHeader("content-type","image/jpeg");

        InputStream in=this.getServletContext().getResourceAsStream("1.jpg");
        //1.jpg 放在WebRoot根目录下

        int len=0;
        byte buffer[]=new byte[1024];

        OutputStream out=resp.getOutputStream();
        while( (len=in.read()) > 0){
            out.write(buffer,0,len);
        }
    }
}