servlet表单处理
1.表单的语法知识
各种组件的标签以及标签中的属性
其中 name 属性很重要，以后用 Servlet 来处理表单数据就是通过这个属性来获取表单组件的数据的
密码是不能显示出来的
name 相同的 radio 就是一组，只有一个能被选中
name 相同的 radio 就是一组，只有一个能被选中
select 中加上 multiple 就是多选了，可以结合键盘使用来选择
2. 试验
2. 试验
简单的登陆页面：
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN" "http://www.w3.org/TR/html4/strict.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8">
<title>Login HTML</title>
</head>
<body>
<form name="loginform" action="/webproject02/servlet/LoginServlet" method="post" accept-charset="utf-8">
<table width="300" border="0">
<tr>
<td colspan="2">请输入用户名和密码：
</td>
</tr>
<tr>
<td>用户名：
</td>
<td><input type="text" name="username" size="20" maxlength="18">
</td>
</tr>
<tr>
<td>密码：
</td>
<td><input type="password" name="password" size="21" maxlength="18">
</td>
</tr>
<tr>
<td><input type="submit" name="submit" value="submit">
</td>
<td><input type="reset" name="reset" value="reset">
</td>
</tr>
</table>
</form>
</body>
</html>
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8">
<title>Login HTML</title>
</head>
<body>
<form name="loginform" action="/webproject02/servlet/LoginServlet" method="post" accept-charset="utf-8">
<table width="300" border="0">
<tr>
<td colspan="2">请输入用户名和密码：
</td>
</tr>
<tr>
<td>用户名：
</td>
<td><input type="text" name="username" size="20" maxlength="18">
</td>
</tr>
<tr>
<td>密码：
</td>
<td><input type="password" name="password" size="21" maxlength="18">
</td>
</tr>
<tr>
<td><input type="submit" name="submit" value="submit">
</td>
<td><input type="reset" name="reset" value="reset">
</td>
</tr>
</table>
</form>
</body>
</html>
LoginServlet 处理程序：主要部分 dePost 方法
public void doPost(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
response.setContentType("text/html");
PrintWriter out = response.getWriter();
out.println("<!DOCTYPE HTML PUBLIC \"-//W3C//DTD HTML 4.01 Transitional//EN\">");
out.println("<HTML>");
out.println(" <HEAD><TITLE>A Servlet</TITLE></HEAD>");
out.println(" <BODY>");
out.print("username:"+request.getParameter("username")+"<br>");
out.print("password:"+request.getParameter("password")+"<br>");
out.println(" </BODY>");
out.println("</HTML>");
out.flush();
out.close();
}
throws ServletException, IOException {
response.setContentType("text/html");
PrintWriter out = response.getWriter();
out.println("<!DOCTYPE HTML PUBLIC \"-//W3C//DTD HTML 4.01 Transitional//EN\">");
out.println("<HTML>");
out.println(" <HEAD><TITLE>A Servlet</TITLE></HEAD>");
out.println(" <BODY>");
out.print("username:"+request.getParameter("username")+"<br>");
out.print("password:"+request.getParameter("password")+"<br>");
out.println(" </BODY>");
out.println("</HTML>");
out.flush();
out.close();
}
