reply.java

浪子学习的留言本 主要功能就是记录留言

package guestbook;

import javax.servlet.*;
import javax.servlet.http.*;
import java.io.*;
import javax.sql.DataSource;
import java.sql.*;

public class reply extends HttpServlet {
  private static final String CONTENT_TYPE = "text/html; charset=GB2312";
  private DataSource dataSource=null;
  private int id;
  //Initialize global variables
  public void init() throws ServletException {
    Init init=new Init(getServletContext().getRealPath("/"));
    dataSource=LinkDB.getDB();
    if (dataSource==null) {
      LinkDB.setDB(init.getDriverName(),init.getDBURL(),init.getDBUser(),init.getDBPassword());
      dataSource=LinkDB.getDB();
    }
  }
  //Process the HTTP Get request
  public void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
    try{
      id = Integer.parseInt(request.getParameter("id"));
    }
    catch(NumberFormatException e){
      throw new RuntimeException("错误的ID号");
    }
    response.sendRedirect("reply.jsp");
  }
  //Process the HTTP Post request
  public void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
    request.setCharacterEncoding("GB2312");
    response.setContentType(CONTENT_TYPE);
    PrintWriter out=response.getWriter();
    String content=request.getParameter("replyContent");
    if(content.getBytes().length>1000){
      out.println("<script>alert('回复内容太长，请不要超过500字');document.location='javascript:history.go(-1);'</script>");
      return;
    }
    content=Check.toHTML(content);
    content=Check.insteadCode(content,"'","''");
    String replytime=Head.getTime();
    Connection conn=null;
    Statement stmt=null;
    try{
      conn=dataSource.getConnection();
      stmt=conn.createStatement(ResultSet.TYPE_SCROLL_SENSITIVE,ResultSet.CONCUR_UPDATABLE);
      int num=stmt.executeUpdate("update guestbook set reply='"+content+"',replytime='"+replytime+"' where id='"+id+"'");
      if(num==0){
        out.println("<script>alert('回复失败，可能ID不存在');document.location='index.jsp';</script>");
      }
      else{
        out.println("<script>alert('回复成功');document.location='index.jsp';</script>");
      }
    }
    catch(SQLException e){
      out.println(e);
    }
    finally {
      try{
        stmt.close();
        conn.close();
        LinkDB.shutdownDataSource(dataSource);
      }
      catch(SQLException e) {
        out.println(e);
      }
    }
  }
}