JavaWeb中对数据维护——以新闻中的主题（增删改查为例）

<body>
	<div id="header">
		<div id="welcome">欢迎使用新闻管理系统！</div>
		<div id="nav">
			<div id="logo">
				<img src="../images/logo.jpg" alt="新闻中国" />
			</div>
			<div id="a_b01">
				<img src="../images/a_b01.gif" alt="" />
			</div>
		</div>
	</div>
	<div id="admin_bar">
		<div id="status">
			管理员： 登录 &#160;&#160;&#160;&#160;<a href="#">login out</a>
		</div>
		<div id="channel"></div>
	</div>
	<div id="main">
		<div id="opt_list">
			<ul>
				<li><a href="newspages/add_new.jsp">添加新闻</a></li>
				<li><a href="WEB-INF/admin.jsp">编辑新闻</a></li>
				<li><a href="#">查找新闻</a></li>
				<li><a href="newspages/add_sub.jsp">添加主题</a></li>
				<li><a href="#">编辑主题</a></li>
			</ul>
		</div>
		<div id="opt_area">
			<h1 id="opt_type">修改主题：</h1>
			<form action="doupda_sub.jsp" method="post">
				主题:<select name="tid">
				<%
			  	Class.forName("oracle.jdbc.driver.OracleDriver");
			  	String url = "jdbc:oracle:thin:@localhost:1521:orcl";
			  	Connection con = DriverManager.getConnection(url, "scott", "tiger");
			  	PreparedStatement ps=con.prepareStatement("select* from subject");
			  	ResultSet rs=ps.executeQuery();
			  	while(rs.next()){
			  		
				%>
					<option value="<%=rs.getInt(1) %>"><%=rs.getString(2) %></option>
				<%} %>
				<option>主题</option>
				</select>
				<p>
					<label> 改为： </label> 
					<input name="tname" type="text" class="opt_input" />
				</p>
				<input name="action" type="hidden" value="addnews"> <input
					type="submit" value="提交" class="opt_sub" /> <input type="reset"
					value="重置" class="opt_sub" />
			</form>
		</div>
	</div>
</body>

<%
    //获取主题的编号
	int tid=Integer.valueOf(request.getParameter("tid"));
    //获取主题名
	String tname=request.getParameter("tname");
    //注册驱动类
	Class.forName("oracle.jdbc.driver.OracleDriver");
     //连接oracle数据库
  	String url = "jdbc:oracle:thin:@localhost:1521:orcl";
  	Connection con = DriverManager.getConnection(url, "scott", "tiger");
         //创建个对象来执行sql语句
  	PreparedStatement ps=con.prepareStatement("update subject set tname=? where tid="+tid);
  	ps.setString(1, tname);
  	int i=ps.executeUpdate();
    //处理结果集
  	if(i>0){
  		out.print("<script>alert('成功成功！！');location.href='update_sub.jsp'</script>");
  	}else{
  		out.print("<script>alert('修改失败！！');location.href='updasub.jsp'</script>");
  	}
%>