Question

我试图以乐透模拟器的形式从网页中获取一组数字。我运行服务器，通过浏览器中的本地主机打开页面，输入数字并提交它，但下一页上没有显示任何内容，甚至没有404错误。可能是一个映射问题，但我迷路了。有什么想法吗？

Lotto.class

 import java.io.*;   
 import java.util.Arrays;
 import java.util.Comparator;

 import javax.servlet.*;
 import javax.servlet.http.*;

 public class Lotto extends HttpServlet {

 public void doGet(HttpServletRequest servletRequest, HttpServletResponse   
 servletResponse)
                           throws ServletException, IOException {

  servletResponse.setContentType("text/html");
  PrintWriter out = servletResponse.getWriter();

  String userInput1 = servletRequest.getParameter("number1");
  int userNum = Integer.parseInt(userInput1);

  String userInput2 = servletRequest.getParameter("number2");
  int userNum2 = Integer.parseInt(userInput2);

  String userInput3 = servletRequest.getParameter("number3");
  int userNum3 = Integer.parseInt(userInput3);

  String userInput4 = servletRequest.getParameter("number4");
  int userNum4 = Integer.parseInt(userInput4);

  String userInput5 = servletRequest.getParameter("number5");
  int userNum5 = Integer.parseInt(userInput5);

  String userInput6 = servletRequest.getParameter("number6");
  int userNum6 = Integer.parseInt(userInput6);


  if(
   userNum != userNum2 || userNum != userNum3 || userNum != userNum4 || 
   userNum != userNum5 || userNum != userNum6 &&
   userNum2 != userNum || userNum2 != userNum3 || userNum2 != userNum4 || 
   userNum2 != userNum5 || userNum2 != userNum6 &&
   userNum3 != userNum || userNum3 != userNum2 || userNum3 != userNum4 || 
  userNum3 != userNum5 || userNum != userNum6 &&
   userNum4 != userNum || userNum4 != userNum2 || userNum4 != userNum3 ||   
  userNum4 != userNum5 || userNum5 != userNum6 &&
   userNum5 != userNum || userNum5 != userNum2 || userNum5 != userNum3 ||   
  userNum5 != userNum4 || userNum5 != userNum6 &&
   userNum6 != userNum || userNum6 != userNum2 || userNum6 != userNum3 || 
  userNum6 != userNum4 || userNum6 != userNum5){

   int[] numberArray = {userNum, userNum2,    
  userNum3,userNum4,userNum5,userNum6,};

    out.println("<html><body>Your numbers selection in order, " +     
  Arrays.toString(numberArray) + "  valid </body></html>");
   }
   else{
    out.println("<html><body> Error! </body></html>");
   }

   }
  }

的index.html

<!DOCTYPE html>
<html>
<body>

 <h1 > Lotto Servlet Game </h1 >
 <h2 > Please choose your numbers below </h2 >

 <form action="Lotto">
 <fieldset>
 Please enter your name: <br><input type="text" name="username"><br>
 #1:<br>
 <input type="text" name="number1" min="1" max="42">
 <br>
 #2:<br>
 <input type="text" name="number1" min="1" max="42">
 <br>
 #3:<br>
 <input type="text" name="number1" min="1" max="42">
 <br>
 #4:<br>
 <input type="text" name="number1" min="1" max="42">
 <br>
 #5:<br>
 <input type="text" name="number1" min="1" max="42">
 <br>
 #6:<br>
 <input type="text" name="number1" min="1" max="42">
 <br><br>
 <input type="submit" min="Submit">
 </fieldset>
 </form>



</body>
</html>

的web.xml

<?xml version="1.0" encoding="ISO-8859-1"?>
<web-app version="2.4" xsi:schemaLocation="http://java.sun.com/xml/ns/j2ee 
                                       http://java.sun.com/xml/ns/j2ee/web-
app_2_4.xsd" xmlns:xsi="
                                       http://www.w3.org/2001/XMLSchema-   
instance" xmlns="
                                       http://java.sun.com/xml/ns/j2ee">


 <display-name>Sample Application</display-name>
 <description> Sample Application. </description>


 <servlet>
   <servlet-name>LottoServlet</servlet-name> 
   <servlet-class>Lotto</servlet-class> 
 </servlet>

 <servlet-mapping>
      <servlet- name>LottoServlet</servlet-name> 
      <url-pattern>/Lotto</url-pattern> 
 </servlet-mapping>
</web-app>

这三个文件包含以下目录：

Lotto.class Z：\ Apache的Tomcat的8.5.5 \ web应用\样品\ WEB-INF \类\ Lotto.class

的index.html Z：\ Apache的Tomcat的8.5.5 \ web应用\样品\ index.html的

的web.xml Z：\ Apache的Tomcat的8.5.5 \ web应用\样品\ WEB-INF \ web.xml中

Answer 1

在index.html中，所有字段名称都是number1。

将这些参数传递给servlet时。它将在您调用Integer.parseInt（userInput2）时抛出异常。

Answer 2

如有疑问，请删除代码。例如，将servlet更改为：

public class Lotto extends HttpServlet {
    public void doGet(HttpServletRequest servletRequest,
                      HttpServletResponse servletResponse)
            throws ServletException, IOException {

        servletResponse.setContentType("text/html");
        PrintWriter out = servletResponse.getWriter();

        out.println("<html><body>You are in the servlet</body></html>");
    }
}

可以告诉你它正在运作。如果你走得那么远，你可以进一步调试。那时你将了解到你的比较逻辑有点搞砸了。但首先，让事情运转起来。正如@adamM所提到的，你可以尝试点击，例如首先在你的浏览器中点击http://localhost:8080/sample/Lotto。

Answer 3

您是否检查过.war文件是否具有正确的结构？即如果你＆＃34;添加框架支持 - ＆gt;网页＆＃34;它创建了web.xml，但是如果你看看你的工件结构是不正确的......

使用以下结构构建工件：

name.war
    -> META-INF
        ->MANIFEST.MF
    ->WEB-INF
        ->lib
            ->required .jars if needed
    ->compile-output (thats the name in IntelliJ)

如果为部署选择了.war文件，请检查运行配置。也许这有帮助，我在tomcat上部署时遇到了很多问题，因为控制台没有提供.war文件不正确的信息。

页面不会加载，Apache Tomcat服务器错误

3 个答案: