topiclistservlet.java

学生信息管理系统 jsp + sql + javabean 实现

package sms.servlet;

import javax.servlet.*;
import javax.servlet.http.*;
import java.io.*;
import java.util.*;
import sms.db.*;
import java.sql.*;
import sms.bean.*;

public class TopicListServlet extends HttpServlet {
    private static final String CONTENT_TYPE = "text/html; charset=gb2312";

    public void init() throws ServletException {
    }

    public void doGet(HttpServletRequest request, HttpServletResponse response) throws
            ServletException, IOException {
        response.setContentType(CONTENT_TYPE);
        request.setCharacterEncoding("gb2312");
        //先得到页面参数
        String column = request.getParameter("columnName");
        String topic = request.getParameter("topic");
        String sql = "select * from messege_info where 1=1";
        if(column != null){
            sql += " and column_id = '" +column +  "'";
        }
        if(topic != null && topic.length() > 0){
          sql += " and topic='"+topic+"'";
        }
        sql += " order by browse_num desc";
        DBAccess dba = new DBAccess();
        ArrayList aList = new ArrayList();
        try {
            dba.getConnection();
            ResultSet rs = dba.query(sql);
            if (rs != null) {
                while (rs.next()) {//从ResultSet中得到留言板信息的内容，保存在MessegeBean中
                    MessegeBean msgBean = new MessegeBean();
                    msgBean.setBrowseNum(rs.getString("browse_num"));
                    msgBean.setTopic(rs.getString("topic"));
                    msgBean.setAuthor(rs.getString("author"));
                    msgBean.setMessegeId(rs.getString("id"));
                    msgBean.setColumnName(rs.getString("column_id"));
                    msgBean.setAddTime(rs.getString("add_Time"));
                    aList.add(msgBean);
                }
            }
        } catch (SQLException ex) {
            System.out.println("TopicListServlet.doGet()中产生异常");
            ex.printStackTrace();
        } finally {
            dba.closeConnection();
        }
        request.setAttribute("messegeBeanList", aList);//将留言板Bean组成的信息保存在request中
        RequestDispatcher dispatcher = request.getRequestDispatcher(
                "viewMessegeBoard.jsp");
        dispatcher.forward(request, response);//将请求转发到viewMessegeBoard.jsp页面
    }

    public void doPost(HttpServletRequest request, HttpServletResponse response) throws
            ServletException, IOException {
        doGet(request, response);
    }

    public void destroy() {
    }
}