noteservlet.java

留言管理程序 jsp+servlet+DAO+MVC实现留言程序

package cn.mldn.lxh.note.servlet ;

import java.io.* ;
import javax.servlet.* ;
import javax.servlet.http.* ;
import cn.mldn.lxh.note.factory.* ;
import cn.mldn.lxh.note.vo.* ;

public class NoteServlet extends HttpServlet
{
	public void doGet(HttpServletRequest request,HttpServletResponse response) throws IOException,ServletException
	{
		this.doPost(request,response) ;
	}
	public void doPost(HttpServletRequest request,HttpServletResponse response) throws IOException,ServletException
	{
		request.setCharacterEncoding("GB2312") ;
		String path = "errors.jsp" ;
		// 接收要操作的参数值
		String status = request.getParameter("status") ;
		if(status!=null)
		{
			// 参数有内容，之后选择合适的方法
			// 查询全部操作
			if("selectall".equals(status))
			{
				try
				{
					request.setAttribute("all",DAOFactory.getNoteDAOInstance().queryAll()) ;
				}
				catch (Exception e)
				{
				}
				path = "list_notes.jsp" ;
			}
			// 插入操作
			if("insert".equals(status))
			{
				// 1、接收插入的信息
				String title = request.getParameter("title") ;
				String author = request.getParameter("author") ;
				String content = request.getParameter("content") ;
				// 2、实例化VO对象
				Note note = new Note() ;
				note.setTitle(title) ;
				note.setAuthor(author) ;
				note.setContent(content) ;
				// 3、调用DAO完成数据库的插入操作
				boolean flag = false ;
				try
				{
					DAOFactory.getNoteDAOInstance().insert(note) ;
					flag = true ;
				}
				catch (Exception e)
				{}
				request.setAttribute("flag",new Boolean(flag)) ;
				path = "insert_do.jsp" ;
			}
			// 按ID查询操作，修改之前需要将数据先查询出来
			if("selectid".equals(status))
			{
				// 接收参数
				int id = 0 ;
				try
				{
					id = Integer.parseInt(request.getParameter("id")) ;
				}
				catch(Exception e)
				{}
				try
				{
					request.setAttribute("note",DAOFactory.getNoteDAOInstance().queryById(id)) ;
				}
				catch (Exception e)
				{
				}				
				path = "update.jsp" ;
			}
			// 更新操作
			if("update".equals(status))
			{
				int id = 0 ;
				try
				{
					id = Integer.parseInt(request.getParameter("id")) ;
				}
				catch(Exception e)
				{}
				String title = request.getParameter("title") ;
				String author = request.getParameter("author") ;
				String content = request.getParameter("content") ;
				Note note = new Note() ;
				note.setId(id) ;
				note.setTitle(title) ;
				note.setAuthor(author) ;
				note.setContent(content) ;
				boolean flag = false ;
				try
				{
					DAOFactory.getNoteDAOInstance().update(note) ;
					flag = true ;
				}
				catch (Exception e)
				{}
				request.setAttribute("flag",new Boolean(flag)) ;
				path = "update_do.jsp" ;
			}
			// 模糊查询
			if("selectbylike".equals(status))
			{
				String keyword = request.getParameter("keyword") ;
				try
				{
					request.setAttribute("all",DAOFactory.getNoteDAOInstance().queryByLike(keyword)) ;
				}
				catch (Exception e)
				{
				}
				path = "list_notes.jsp" ;
			}
			// 删除操作
			if("delete".equals(status))
			{
				// 接收参数
				int id = 0 ;
				try
				{
					id = Integer.parseInt(request.getParameter("id")) ;
				}
				catch(Exception e)
				{}
				boolean flag = false ;
				try
				{
					DAOFactory.getNoteDAOInstance().delete(id) ;
					flag = true ;
				}
				catch (Exception e)
				{}
				request.setAttribute("flag",new Boolean(flag)) ;
				path = "delete_do.jsp" ;
			}
		}
		else
		{
			// 则表示无参数，非法的客户请求
		}
		request.getRequestDispatcher(path).forward(request,response) ;
	}
};
/*
  <servlet>
	<servlet-name>note</servlet-name>
	<servlet-class>cn.mldn.lxh.note.servlet.NoteServlet</servlet-class>
  </servlet>
  <servlet-mapping>
	<servlet-name>note</servlet-name>
	<url-pattern>/note/note_mvc/Note</url-pattern>
  </servlet-mapping>
*/