404错误（Servlet） [英] 404 Error (Servlet)

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本文介绍了404错误（Servlet）的处理方法，对大家解决问题具有一定的参考价值，需要的朋友们下面随着小编来一起学习吧！

问题描述

我想编写自己的JavaEE-App。我使用Linux Mint和Glassfish 4作为App-Server。我的Eclipse是Oxygen（EE版）。



我想测试我的客户是否可以登录。



我还没有包含CSS，所以它可能看起来有点无聊。 ：D



这些是我在Eclipse中使用的项目：
$ b



这是我的索引HTML： 

 < ;! DOCTYPE html> 
< html> 
< head> 
< meta charset =UTF-8/> 
< link rel =stylesheethref =css / styles.css> 
< title>网上商店< /标题> 
< / head> 
< body> 
< header> 
< hgroup> 
< h1 class =title>网上商店< / h1> 
< / hgroup> 
< nav> 
< a href =index.html>主页< / a> 
< a href =register.html> Registrieren< / a> 
< a href =signin.html> Einloggen< / a> 
< a href =sell.html> Verkaufen< / a> 
< a href =search.html> Suchen< / a> 
< / nav> 
< / header> 
 
< footer> 
版权
< / footer> 
< / body>



Registrieren的意思是sign Einloggen意为登录，Verkaufen意味着卖，Suchen意思是搜索。

这是HTML - 点击Registrieren后显示的地点： 

 <！DOCTYPE html> 
< html> 
< head> 
< meta charset =UTF-8/> 
< link rel =stylesheethref =css / styles.css> 
< title>网上商店< /标题> 
< / head> 
< body> 
< header> 
< hgroup> 
< h1 class =title>网上商店< / h1> 
< / hgroup> 
< nav> 
< a href =index.html>主页< / a> 
< a href =register.html> Registrieren< / a> 
< a href =signin.html> Einloggen< / a> 
< a href =sell.html> Verkaufen< / a> 
< a href =search.html> Suchen< / a> 
< / nav> 
< / header> 
< form action =registermethod =post> 
< fieldset> 
< legend> Registrieren< / legend> 
< table> 
< tbody> 
< tr> 
< th> 
< label for =email>电子邮件：< / label> 
< / th> 
< td> 
< input 
 type =email
 name =email
 size =40
 maxlength =40
 title = muster@beispiel.de
 placeholder =E-Mail eingeben
 pattern =。{6,40}
 required =required> 
< / td> 
< / tr> 
< tr> 
< th> 
< label for =password> 
密码：
< / label> 
< / th> 
< td> 
< input 
 type =password
 name =password
 size =10
 maxlength =10
 title = 6-10 Zeichen
 placeholder = 
Passwort eingeben
 pattern =。{6,10}
 required =required> 
< / td> 
< / tr> 
< tr> 
< td>< td> 
< input type =submit> 
< input type =reset> 
< / td> 
< / tr> 
< / tbody> 
< / table> 
< / fieldset> 
< / form> 
 
< footer> 
版权
< / footer> 
< / body>



这是我的Servlet：

  package de.java2enterprise.onlineshop; 
 
 import java.io.IOException; 
 import java.io.PrintWriter; 
 
 import javax.servlet.ServletException; 
 import javax.servlet.annotation.WebServlet; 
 import javax.servlet.http.HttpServlet; 
 import javax.servlet.http.HttpServletRequest; 
 import javax.servlet.http.HttpServletResponse; 
 
 
 @WebServlet（/ register）
 public class RegisterServlet扩展HttpServlet {
 private static final long serialVersionUID = 1L; 
 
 / ** 
 *默认构造函数。 
 * / 
 public RegisterServlet（）{
 // TODO自动生成的构造函数存根
} 
 
 / ** 
 * HttpServlet＃doPost（HttpServletRequest请求，HttpServletResponse 
响应）
 * / 
保护无效doPost（HttpServletRequest请求，HttpServletResponse 
响应）
抛出ServletException，IOException {
 
 response.setContentType（text / html; charset = UTF-8）; 
 
 final String email = request.getParameter（email）; 
 final String password = request.getParameter（password）; 
 
 final PrintWriter out = response.getWriter（）; 
 
 out.println（<！DOCTYPE html>）; 
 out.println（< html>）; 
 out.println（< body>）; 
 out.println（< br> Ihre Eingaben）; 
 out.println（< br> EMail：+ email）; 
 out.println（< br> EMail：+密码）; 
 out.println（< / body>）; 
 out.println（< / html>）; 
 
} 
 
}

写一个Web.xml是因为我只是想用注解来应付它。
现在我有两个问题：



所有Servlet-API的导入都无法解析。但为什么？我确实创建了一个
的Java-Enterprise-Application-Project，并将Webproject onlineshop-war分配给该应用程序。 Glassfish被分配到Java-Enterprise-Application-Project，而Glassfish-Server则被记录到Servlet-API中，不是吗？

和第二个问题：
为什么在输入寄存器HTML中的电子邮件和密码后点击提交后，他找不到Servlet？是否与问题1有关？



非常感谢！

解决方案

第一个问题 -


无法解析所有Servlet-API的导入。但为什么？我做
创建一个Java-Enterprise-Application-Project，并将
Webproject onlineshop-war分配给应用程序。 Glassfish被分配给
的Java-Enterprise-Application-Project，而Glassfish-Server则被分配到
的Servlet-API记录，不是吗？
blockquote>

我使用 eclipse 结合 Java-8 和通过观察你的问题，我简单地在eclipse中创建了一个新的动态Web项目，稍后创建了两个 Tomcat 8.5 web容器 html文件 index.html 和 register.html 以及 Servlet类RegisterServlet

完成所有工作后，我只是首先启动并停止了我的Web容器服务器，稍后再制作a 右键单击项目名称，转到菜单运行方式>在服务器上运行>选择一个现有的服务器，我选择Tomcat 8.5服务器在localhost>从列表中删除所有其他项目而不是当前项目并按下完成。



之前我已经选择了我已经通过步骤选择了默认浏览器选项窗口（菜单）>网络浏览器> Chrome 。



没有这样的web.xml配置文件目录WebContent / WEB-INF /在我的项目中。

因此， Tomcat 8.5服务器将启动并显示 index.html 页面 chrome 新标签页，其中 Optionshop页面出现了，我选择了 Registrieren 链接，然后重定向到 register.html ，我在那里插入了电子邮件ID和密码输入和 servlet映射在新页面中查看了我的电子邮件ID和密码，就是这样。



第二个问题 -
$ b


为什么在输入
之后点击提交后找不到Servlet？和密码在寄存器HTML？是否有问题1
？

我更改了 @WebServlet 到 / RegisterServlet 和 register.html 我将表格的开始标记替换为

 < form name =registermethod =POSTaction =RegisterServlet>

也在 Servlet 类中，方法 doGet（HttpServletRequest请求，HttpServletResponse响应）缺少，所以我创建了一个，我的 Servlet 类如下所示：

  package de.java2enterprise.onlineshop; 
 
 import java.io.IOException; 
 import java.io.PrintWriter; 
 
 import javax.servlet.ServletException; 
 import javax.servlet.annotation.WebServlet; 
 import javax.servlet.http.HttpServlet; 
 import javax.servlet.http.HttpServletRequest; 
 import javax.servlet.http.HttpServletResponse; 
 
 @WebServlet（/ RegisterServlet）
 public class RegisterServlet扩展HttpServlet {
 private static final long serialVersionUID = 1L; 
 $ b $ public RegisterServlet（）{} 
 
 protected void doGet（HttpServletRequest请求，HttpServletResponse响应）
 throws ServletException，IOException {} 
 
 protected void doPost（HttpServletRequest请求，HttpServletResponse响应）
 throws ServletException，IOException {
 
 response.setContentType（text / html）; 
 
 final String email = request.getParameter（email）; 
 final String password = request.getParameter（password）; 
 
 final PrintWriter out = response.getWriter（）; 
 
 out.println（<！DOCTYPE html>）; 
 out.println（< html>）; 
 out.println（< body>）; 
 out.println（< br> Ihre Eingaben）; 
 out.println（< br> EMail：+ email）; 
 out.println（< br> EMail：+密码）; 
 out.println（< / body>）; 
 out.println（< / html>）; 
 
 out.close（）;

希望这会对你有所帮助，谢谢。


I'd like to code my own JavaEE-App. I'm using Linux Mint and Glassfish 4 as an App-Server. My Eclipse is Oxygen (EE-Version).

I'd like to test if my Costumer is able to sign in.

I haven't include CSS yet so it might look a bit boring. :D

These are my projects in Eclipse:

This is my Index-HTML: 

<!DOCTYPE html>
<html>
<head>
    <meta charset="UTF-8"/>
   <link rel="stylesheet" href="css/styles.css">
   <title>Onlineshop</title>
</head>
<body>
    <header>
        <hgroup>
        <h1 class="title">Onlineshop</h1>
        </hgroup>
        <nav>
          <a href="index.html">Home</a>
          <a href="register.html">Registrieren</a>
          <a href="signin.html">Einloggen</a>
          <a href="sell.html">Verkaufen</a>
          <a href="search.html">Suchen</a>
        </nav>
</header>

<footer>
        Copyright
</footer>
</body>

"Registrieren" means "sign up", "Einloggen" means "to log in", "Verkaufen" means "to sell" and "Suchen" means "to search".

This is the HTML-Site which is displayed after clicking on "Registrieren":

<!DOCTYPE html>
<html>
<head>
    <meta charset="UTF-8"/>
<link rel="stylesheet" href="css/styles.css">
   <title>Onlineshop</title>
</head>
<body>
    <header>
        <hgroup>
        <h1 class="title">Onlineshop</h1>
        </hgroup>
        <nav>
          <a href="index.html">Home</a>
          <a href="register.html">Registrieren</a>
          <a href="signin.html">Einloggen</a>
          <a href="sell.html">Verkaufen</a>
          <a href="search.html">Suchen</a>
        </nav>
</header>
<form action="register" method="post">
<fieldset>
<legend>Registrieren</legend>
<table>
    <tbody>
    <tr>
        <th>
            <label for="email">Email:</label>
        </th>
        <td>
            <input 
                type="email" 
                name="email"
                size="40"
                maxlength="40"
                title="muster@beispiel.de"
                placeholder="E-Mail eingeben"
                pattern=".{6,40}" 
                required="required">
        </td>
    </tr>
    <tr>
        <th>
            <label for="password">
                Password:
            </label>
        </th>
        <td>
            <input 
                type="password" 
                name="password"
                size="10"
                maxlength="10"
                title="6-10 Zeichen"
                placeholder=
                    "Passwort eingeben"
                pattern=".{6,10}" 
                required="required">
        </td>
    </tr>
    <tr>
        <td/><td>
            <input type="submit">       
            <input type="reset">        
        </td>
    </tr>
</tbody>
</table>
</fieldset>
</form>

<footer>
        Copyright 
</footer>
</body>

This is my Servlet:

package de.java2enterprise.onlineshop;

import java.io.IOException;
import java.io.PrintWriter;

import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;


@WebServlet("/register")
public class RegisterServlet extends HttpServlet {
private static final long serialVersionUID = 1L;

/**
 * Default constructor. 
 */
public RegisterServlet() {
    // TODO Auto-generated constructor stub
}

/**
 * @see HttpServlet#doPost(HttpServletRequest request, HttpServletResponse    
  response)
 */
protected void doPost(HttpServletRequest request, HttpServletResponse 
 response) 
        throws ServletException, IOException {

    response.setContentType("text/html;charset=UTF-8");

    final String email = request.getParameter("email");
    final String password = request.getParameter("password");

    final PrintWriter out = response.getWriter();

    out.println("<!DOCTYPE html>");
    out.println("<html>");
    out.println("<body>");
    out.println("<br> Ihre Eingaben");
    out.println("<br> EMail: " + email);
    out.println("<br> EMail: " + password);
    out.println("</body>");
    out.println("</html>");

 }

}

I didn't write an Web.xml because i just want to cope it with annotations. Now I have 2 questions:

All the imports of the Servlet-API can't be resolved. But why? I did create a Java-Enterprise-Application-Project and assigned the Webproject onlineshop-war to the App. And the Glassfish is assigned to the Java-Enterprise-Application-Project and on the Glassfish-Server is the Servlet-API recorded, isn't it?

And the Second question: Why can't he find the Servlet after clicking on submit after typing in the EMail and the Password on the register-HTML? Has it something to do with question 1?

Thank you very much!

解决方案

First Question -

All the imports of the Servlet-API can't be resolved. But why? I did create a Java-Enterprise-Application-Project and assigned the Webproject onlineshop-war to the App. And the Glassfish is assigned to the Java-Enterprise-Application-Project and on the Glassfish-Server is the Servlet-API recorded, isn't it?

I am using eclipse with combination of Java-8 and Tomcat 8.5 web container, by watching your question, I simply created a new dynamic web project in eclipse, later created two html files index.html and register.html along with Servlet class RegisterServlet in the same package you defined.

After doing all work, I simply first started and stopped my web container server, later make a Right click on the project name, Go to menu Run As > Run on Server > Choose an existing server, there I choose the Tomcat 8.5 Server at localhost > Remove all other projects from list Configured instead the current one and pressed the Finish.

Earlier I have selected I have selected the default browser by steps option Window(Menu)>Web Browser>Chrome.

No such web.xml configuration file is there in directory WebContent/WEB-INF/ inside my project.

Thus the Tomcat 8.5 server will start and show the index.html page in chrome new tab, there Optionshop page appeared and I chose the Registrieren link, then redirected to register.html, there I inserted email id and password later pressed Enter and the servlet mapping viewed me my email id and password in fresh page, that's it.

Second Question -

Why can't he find the Servlet after clicking on submit after typing in the EMail and the Password on the register-HTML? Has it something to do with question 1?

I changed the @WebServlet to /RegisterServlet and in register.html I replaced the form starting tag to 

<form name="register" method="POST" action="RegisterServlet">

also in Servlet class the method doGet(HttpServletRequest request, HttpServletResponse response) was missing, so I create one and my Servlet class is as follows:

package de.java2enterprise.onlineshop;

import java.io.IOException;
import java.io.PrintWriter;

import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

@WebServlet("/RegisterServlet")
public class RegisterServlet extends HttpServlet {
    private static final long serialVersionUID = 1L;

    public RegisterServlet() { }

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

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

        response.setContentType("text/html");

        final String email = request.getParameter("email");
        final String password = request.getParameter("password");

        final PrintWriter out = response.getWriter();

        out.println("<!DOCTYPE html>");
        out.println("<html>");
        out.println("<body>");
        out.println("<br> Ihre Eingaben");
        out.println("<br> EMail: " + email);
        out.println("<br> EMail: " + password);
        out.println("</body>");
        out.println("</html>");

        out.close();
    }
}

Hope this will help you, thanks.

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