Question

PersonalInfoOutput.java servlet正在使用doPost方法。用户登录 index.html 。 从index.html，请求将发送到Login.java servlet。

从那里，用户被定向到PersonalInfoOutput.java servlet。

现在，请考虑另一个名为 ChangePassAdmin.html 的网页。在此html代码中，其中一个

转到PersonalInfoOutput.java。但是，当我从该页面点击它时，

我得到 HTTP Status 405 - HTTP method GET is not supported by this URL 。

有人可以帮助我解决这个问题吗？

我尝试将PersonalInfoOutput.java更改为doGet instead of doPost，但随后Login.java servlet将返回 HTTP Status 405 - HTTP method POST is not supported by this URL 。所以我似乎需要这个PersonalInfoOutput.java servlet的doGet和doPost。

PersonalInfoOutput.java（servlet）

import java.io.*;
import javax.servlet.*;
import javax.servlet.http.*;
import java.sql.*;

public class PersonalInfoOutput extends HttpServlet {

    protected void doPost(HttpServletRequest request, HttpServletResponse response)
            throws ServletException, IOException {
            response.setContentType("text/html;charset=UTF-8");
            PrintWriter out = response.getWriter();

            HttpSession session = request.getSession(false);
            String employeeid = ""; 

                       if(session != null) { 
                           employeeid = (String)session.getAttribute("employeeid"); 
                       }


            boolean st = false;
            try { 
                Class.forName("com.mysql.jdbc.Driver").newInstance(); 
                Connection con = DriverManager.getConnection("jdbc:mysql://localhost:3306/payroll_system", "root", ""); 
                PreparedStatement ps = con.prepareStatement("select employeeID,  FirstName, LastName, Admin, DOB, Address, Email, HourlyRate, Gender, ALeaveBalance, SLeaveBalance, ActiveStatus, Role, BSB, BankName, AccNumber, SuperNumber, SuperCompany from payroll_system.employee_info where employeeID = ?");
                ps.setString(1, employeeid);
                ResultSet rs = ps.executeQuery(); 
                st = rs.next(); 
                if(st){
                etc... (rest of the code isn't relevant to question)

的index.html

<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<link rel = "stylesheet" type = "text/css" href = "main.css">
<title>Login</title>
</head>
<body>
<form action="Login" method="post">
<h1>
Login
</h1>
 <b>Employee ID:</b> <br>
 <input type="text"name="employee_id" size="20"><br><br>
<b>Password:</b><br>
<input type="password" name="password" size="20"><br><br>
<input type="submit" value="Login"><br><br>
</form>
</body>
</html>

Login.java（servlet）

import java.io.*;
import javax.servlet.*;
import javax.servlet.http.*;
import java.sql.*;

public class Login extends HttpServlet {

    protected void doPost(HttpServletRequest request, HttpServletResponse response)
            throws ServletException, IOException {
        response.setContentType("text/html;charset=UTF-8");
        PrintWriter out = response.getWriter();

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

        HttpSession session = request.getSession(); 
        session.setAttribute("employeeid", employee_id);

        if(ValidateLogin.user(employee_id, password)) { 
            RequestDispatcher rs = request.getRequestDispatcher("PersonalInfoOutput");
            rs.forward(request, response);
        }
        else
        {
           out.print("Employee ID or Password is incorrect. Please try again.");
           RequestDispatcher rs = request.getRequestDispatcher("index.html");
           rs.include(request, response);
        }
    }  


        }

ChangePassAdmin.html

<!DOCTYPE html> 
<html> 
<head> 
<meta charset = "UTF-8"> 
<link rel = "stylesheet" type = "text/css" href = "main.css">
<link rel = "stylesheet" type = "text/css" href = "sidebar.css">
<title>Change Password</title>
<style>
table { border-collapse: collapse; width: 50%; } th, td { text-align: left; padding: 8px; } tr:nth-child(even){background-color: #f2f2f2}
tr:hover {background-color: #e2f4ff;}
</style>
</head>

<body>

<ul>

<li><a  href=PersonalInfoOutput>View Personal Information</a></li>
<li><a  href=PersonalInfoOutput>View Expense Claims</a></li>
<li><a  href=PersonalInfoOutput>View Payslips</a></li>
<li><a  class=active >Change Password</a></li>
<li><a  href=PersonalInfoOutput>Maintain Employee Information</a></li>
<li><a  href=PersonalInfoOutput>Maintain Tax Information</a></li>
<li><a  href=PersonalInfoOutput>Maintain Payroll Items</a></li>
<li><a  href=PersonalInfoOutput>Maintain Timesheet</a></li>
<li><a  href=PersonalInfoOutput>Maintain Employee Expenses</a></li>
<li><a  href=PersonalInfoOutput>Run Payroll</a></li>
<li><a  href=PersonalInfoOutput>Generate Reports</a></li>

</ul>

<div style=margin-left:25%;padding:1px;>
</div>

<div id="container">
    <h1>Change Password</h1>
    <form action ="NewPassword" method = post> 

    <table border ="1"> 

    <tr>
    <td>Existing Password:</td>
    <td><input type = "password" name = "oldpassword" size = "20"></td>
    </tr>

    <tr>
    <td>New Password:</td>
    <td><input type = "password" name = "newpassword" size = "20"></td>
    </tr>

    <tr>
    <td>Confirm New Password</td>
    <td><input type = "password" name = "confirmpassword" size = "20"></td>
    </tr>
    </table>
    <br>
    <br>
    <input type = "submit" value = "Update Password">
    </form>.
    </div>
</body>

</html>

Answer 1

在ChangePassAdmin.html中，帖子周围的双引号丢失。您的表单使用时，您的Servlet都应该使用doPost方法＆＃34; post＆＃34;行动。

<form action ="NewPassword" method = "post">

此外，在这种情况下您需要两种方法。在servlet中添加doGet和doPost。表单和doGet将通过链接使用doPost。默认情况下，所有链接都是GET。你可以这样做：

修改

public class PersonalInfoOutput extends HttpServlet { protected void processRequest(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { // Your servlets code should be here } @Override protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { processRequest(request, response); } @Override protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { processRequest(request, response); }

doPost()方法，用于接收基于form的请求。 doGet()方法，用于接收基于href的请求。但在这两种情况下都会调用processRequest()方法。

Answer 2

我认为问题在于您以两种方式使用PersonalInfoOutput servlet：

从登录servlet转发，通过转发继续使用POST方法
来自HTML的href，默认情况下使用方法GET

对于您来说，重构代码不是一个可能的解决方案，这对您来说很有帮助，因此您可以在doGet()中同时实现doPost()和PersonalInfoOutput servlet没有重复很多代码？

或者您可以将员工数据库检索重构为外部类，该外部类将从Login调用而无需从一个servlet重定向到另一个servlet，并在PersonalInfoOutput中实现GET而不是POST。

我遇到了doGet和doPost方法的问题

2 个答案: