Question

这是我第一次设置Java Servlet，我试图在用户单击特定按钮时从JSP表单中的输入字段中将值检索到Java Servlet中。我也不确定我是否使用了正确的做法来创建我的Servlet。我只需右键单击我的Apache Tomcat 8.0服务器，然后选择新的Servlet。

Java Servlet：

@WebServlet("/loginServlet")
public class loginServlet extends HttpServlet {

    private static final long serialVersionUID = 3719628899527775749L;

    public loginServlet() {
        super();
    }

    protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        response.getWriter().append("Served at: ").append(request.getContextPath());
    }

    protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {

        String username = request.getParameter("username");
        String password = request.getParameter("password");

        // do some processing here...

        // get response writer
        PrintWriter writer = response.getWriter();

        // build HTML code
        String htmlRespone = "<html>";
        htmlRespone += "<h2>Your username is: " + username + "<br/>";      
        htmlRespone += "Your password is: " + password + "</h2>";    
        htmlRespone += "</html>";

        // return response
        writer.println(htmlRespone);
    }
}

JSP：

<form name="loginForm" action="loginServlet" method="post" id="loginForm">
            <div class="imgcontainer">
                <img src="images/img_avatar2.png" alt="Avatar" class="avatar">
            </div>

            <div class="container">
                <label><b>Username</b></label>
                <input type="text" placeholder="Enter Username" name="uname" required>

                <label><b>Password</b></label>
                <input type="password" placeholder="Enter Password" name="psw" required>

                <button id="loginButton" name="loginButton" type="submit">Login</button>
                <button id="registerButton" name="registerButton" type="button">Register</button>
                <input type="checkbox" checked="checked"> Remember me
            </div>

            <div class="container" style="background-color:#f1f1f1">
                <button type="button" class="cancelbtn">Cancel</button>
                <span class="psw">Forgot <a href="#">password?</a></span>
            </div>
        </form>

Answer 1

您的请求属性的名称是{J}页面上添加的uname和psw。所以你必须像这样改变你的doPost方法。

String username = request.getParameter("uname");
String password = request.getParameter("psw");

或

您必须在jsp页面中更改您的表单，如下所示：

<label><b>Username</b></label>
<input type="text" placeholder="Enter Username" name="username" required>
<label><b>Password</b></label>
<input type="password" placeholder="Enter Password" name="password" required>

Java Servlet没有从JSP Form接收值

1 个答案: