package csdn.servlet;
import java.io.File;
import java.io.FileInputStream;
import java.io.IOException;
import java.io.PrintWriter;
import javax.servlet.ServletException;
import javax.servlet.ServletOutputStream;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
public class DemoServlet extends HttpServlet {
public void doGet(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
showImg(request, response);
// downImg(request, response);
}
public void doPost(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
this.doGet(request, response);
}
public void showImg(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
response.setContentType("image/jpeg ");
//获取项目绝对路径
String p = this.getServletContext().getRealPath("/");
//图片的路径
File file = new File(p+"./images/3.jpg");
//创建文件的输入流
FileInputStream is = new FileInputStream(file);
//响应的输出流
ServletOutputStream out = response.getOutputStream();
//读取缓冲区
byte buffer[] = new byte[1024];
int len = 0;//记录读取的长度
while ((len = is.read(buffer)) != -1) {
out.write(buffer, 0, len);//写入
}//释放资源
is.close();
out.flush();
out.close();
}
public void downImg(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
//
String p = this.getServletContext().getRealPath("/");
File file = new File(p + "/images/j.jpg");
FileInputStream is = new FileInputStream(file);
response.setHeader("Content-Disposition", "attachment;filename="+file.getName());
ServletOutputStream out = response.getOutputStream();
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();
}
}

