Javaweb中,使用Servlet编写简单的接口

案例:网页提交用户名和密码信息,后端校验密码长度需在6-12位之间

  1. 后端部分

    @WebServlet("/valid")
    public class SimpleServlet extends HttpServlet{
    	public void service(HttpServletRequest req, HttpServletResponse resp) throws IOException{
    		// 获取请求参数
    		String username = req.getParameter("username");
    		String password = req.getParameter("password");
    		// 校验密码长度需在6-12位之间
    		String result = "NO";
    		if (password.length() >= 6 && password.length() <= 12) {
    			result = "YES";
    		}
    		// 将结果写入到响应体中
    		PrintWriter writer = resp.getWriter();
    		writer.write(result);
    	}
    }
    
  2. 前端部分

    <form action="valid" method="post">
    	<div>
    		<span>用户名:span>
    		<input type="text" name="username">
    	div>
    	<div>
    		<span>密码:span>
    		<input type="password" name="password">
    	div>
    	<button type="submit">提交button>
    form>
    

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