viewmessages_servlet.java

来自「Internet 开发技术分章节代码和自己完成的课程设计全代码（在zuoye文件」· Java 代码 · 共 70 行

package message;
import javax.servlet.*;
import javax.servlet.http.*;
import java.sql.*;
import java.util.ArrayList;
import java.util.Collection;
import java.io.*;
 public class ViewMessages_servlet extends javax.servlet.http.HttpServlet implements javax.servlet.Servlet
 {
	 //连接数据库
	 public ViewMessages_servlet()
		{
	    	 String JDriver = "sun.jdbc.odbc.JdbcOdbcDriver"; //声JDBC驱动程序对象
			   String conURL="jdbc:odbc:message"; //定义JDBC的URL对象
			   try {
			     Class.forName(JDriver); //加载JDBC-ODBC桥驱动程序
			     con=DriverManager.getConnection(conURL); //连接数据库URL
			     }
			   catch(Exception e)
			     {  System.err.println(e.getMessage()); }
		}		
	 private Connection con;
	// 得到GET请求，从数据库中读出留言信息
	 public void doGet(HttpServletRequest request,HttpServletResponse response)
	        throws IOException, ServletException
	    {
		 Collection ret=new ArrayList();
			try
			{
				Statement stm=con.createStatement();
				ResultSet result=stm.executeQuery("select count(*) from  MessageTable");		
				int message_count=0;
				if(result.next())
				{
					message_count=result.getInt(1);
					result.close();			
				}
				if(message_count>0)
				{
					result=stm.executeQuery("select * from MessageTable");
					
					while(result.next())
					{ 			
						String title=result.getString("title");
						String name=result.getString("name");
						String email=result.getString("email");
						String content=result.getString("content");
						//将数据保存到MessageDataBean中
						MessageDataBean message=new MessageDataBean();
						message.setTitle(title);
						message.setName(name);
						message.setEmail(email);
						message.setContent(content);
						ret.add(message);						
					}
				result.close();
				stm.close();
				}
		    //访问显示留言的JSP
				request.setAttribute("messages",ret);
				RequestDispatcher requestDispatcher = request.getRequestDispatcher("viewMessages.jsp");
			    requestDispatcher.forward(request,response);
			}
			catch(Exception e){	e.printStackTrace();}
	    }  
	   	public void doPost(HttpServletRequest request,HttpServletResponse response)
		        throws IOException, ServletException
		    {  	doGet(request,response);    }
	}