studentfileservlet.java

采用Eclispe开发平台

package com.whatratimes.util;

import com.whatratimes.dbms.QuerySQLExecuter;
import com.whatratimes.tables.t_exam_question_upload;

import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.ServletException;
import java.io.IOException;
import java.io.OutputStream;

public class StudentFileServlet extends HttpServlet
{
    private static int index = 0;

    protected void service(HttpServletRequest httpServletRequest, HttpServletResponse httpServletResponse) throws ServletException, IOException
    {

        OutputStream os = httpServletResponse.getOutputStream();
        StringBuffer sb = new StringBuffer(httpServletRequest.getPathInfo());

        try
        {
            sb.deleteCharAt(0);
            Integer upload_id = Integer.valueOf(sb.substring(0,sb.indexOf("/")).toString());


            QuerySQLExecuter sql = new QuerySQLExecuter();
            sql.setReturnClassName("t_exam_question_upload");
            sql.appendTableName("t_exam_question_upload");
            sql.appendColumn("*");
            sql.appendWhereCondition("UploadId", "=", upload_id);

            Object[] objs = sql.executeQuery();

            if (objs.length > 0)
            {
                t_exam_question_upload qf = (t_exam_question_upload) objs[0];

                httpServletResponse.setContentType(qf.FileType);
                httpServletResponse.setContentLength(qf.FileSize);

                os.write( (byte[]) qf.FileContent );
                return;
            }
        } catch (Exception e)
        {
//            e.printStackTrace();
        }

        httpServletResponse.setStatus(HttpServletResponse.SC_NOT_FOUND);
    }
}