1。这里会连接数据库--JDBC的学习实例

一共有3个页面。

2.第一个页面是一个form表单，第二个页面是处理数据，第三个页面是显示页面

vote.jsp

<body bgcolor="green">

   	选择你要投票的人：
    <form action="vote_end.jsp">
    	<input type="radio" name="pp" value="a"/>周杰伦<img src="img/a.jpg"/>
    	<br><input type="radio" name="pp" value="b"/>张   杰<img src="img/b.jpg"/>
    	<br><input type="radio" name="pp" value="c"/>范冰冰<img src="img/c.jpg"/>
    	<br><input type="radio" name="pp" value="d"/>赵  薇<img src="img/d.jpg"/>
    	<br><input type="radio" name="pp" value="e"/>黄晓明<img src="img/e.jpg"/>
    	<br><br><input type="submit" value="提交"/>
    </form>
  </body>

　　vote_end2.jsp

<body bgcolor="red">
  	<center>
    <%
    	String sess = request.getSession().getId();
    	String sess2 = null;
    
    
    	out.print("恭喜你，投票成功。<br>");
    	
    	String pp = request.getParameter("pp");
    	String people = null;
    	if(pp.equals("a")){
			people="'周杰伦'";
		}else if(pp.equals("b")){
			people="'张杰'";
		}else if(pp.equals("c")){
			people="'范冰冰'";
		}else if(pp.equals("d")){
			people="'赵薇'";
		}else if(pp.equals("e")){
			people="'黄晓明'";
		}
    	
		Class.forName("com.mysql.jdbc.Driver");
		Connection connection=DriverManager.getConnection("jdbc:mysql://localhost/test?user=root&password=123&useUnicode=true&characterEncoding=gbk");
		Statement statement = connection.createStatement();
		
		//查看是否投过票
		ResultSet rs2 = statement.executeQuery("SELECT * FROM sess");
		while(rs2.next()){
			sess2 = rs2.getString("id");
			if(sess2.equals(sess)){
				%>
					<jsp:forward page="vote_no.jsp"/>
				<% 
			}
		}
		
		
		//查找数据库
		ResultSet rs = statement.executeQuery("SELECT * FROM people where name="+people);
		rs.next();
		int count = rs.getInt("count");
		count = count+1;
		//更新数据库
		statement.executeUpdate("UPDATE people SET count="+count+" where name="+people);
		
		//投票session号保存到数据库

		statement.executeUpdate("insert into sess values('"+sess+"')");
		
		
		//显示数据库
		ResultSet rss = statement.executeQuery("SELECT * FROM people");
		out.print("<table border=1>");
		out.print("<tr>");
		out.print("<th>姓名</th>");
		out.print("<th>票数</th>");
		out.print("</tr>");
		while(rss.next()) {
			out.print("<tr>");
			out.print("<td>"+rss.getString(1)+"</td>");
			out.print("<td>"+rss.getString(2)+"</td>");
			out.print("</tr>");
		}
		out.print("</table>");
		rs.close();
		statement.close();
		connection.close();

     %>
     
     </center>
  </body>

　　vote_end.jsp

<body bgcolor="red">
  	<center>
    <%

    
    
    
    	out.print("恭喜你，投票成功。<br>");
    	
    	String pp = request.getParameter("pp");
    	String people = null;
    	if(pp.equals("a")){
			people="'周杰伦'";
		}else if(pp.equals("b")){
			people="'张杰'";
		}else if(pp.equals("c")){
			people="'范冰冰'";
		}else if(pp.equals("d")){
			people="'赵薇'";
		}else if(pp.equals("e")){
			people="'黄晓明'";
		}
    	
		Class.forName("com.mysql.jdbc.Driver");
		Connection connection=DriverManager.getConnection("jdbc:mysql://localhost/test?user=root&password=123&useUnicode=true&characterEncoding=gbk");
		Statement statement = connection.createStatement();
		//查找数据库
		ResultSet rs = statement.executeQuery("SELECT * FROM people where name="+people);
		rs.next();
		int count = rs.getInt("count");
		count = count+1;
		//更新数据库
		statement.executeUpdate("UPDATE people SET count="+count+" where name="+people);
		
		
		
		//显示数据库
		ResultSet rss = statement.executeQuery("SELECT * FROM people");
		out.print("<table border=1>");
		out.print("<tr>");
		out.print("<th>姓名</th>");
		out.print("<th>票数</th>");
		out.print("</tr>");
		while(rss.next()) {
			out.print("<tr>");
			out.print("<td>"+rss.getString(1)+"</td>");
			out.print("<td>"+rss.getString(2)+"</td>");
			out.print("</tr>");
		}
		out.print("</table>");
		rs.close();
		statement.close();
		connection.close();

     %>
     </center>
  </body>