请求分析
表单的action属性值是Jsp1.jsp，这意味着请求（包括上载的文件）将发送给Jsp1.jsp文件。Jsp1.jsp简单地调用名为SimpleBean的JavaBean。

<%
TheBean.doUpload(request);
%>

下面是SimpleBean的实现代码：
import java.io.*;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.ServletInputStream;

public class FileUploadBean {

public void doUpload(HttpServletRequest request) throws
IOException {
PrintWriter pw = new PrintWriter(
new BufferedWriter(new FileWriter("Demo.out")));
ServletInputStream in = request.getInputStream();

int i = in.read();
while (i != -1) {
pw.print((char) i);
i = in.read();
}
pw.close();
}
}