[英]Jetty - Servlet cannot be found
我是Servlets的新手,想通過使用Eclipse的Jetty插件調用一個簡單的Servlet。 我可以調用index.html,但是當我嘗試訪問Servlet時,我得到:
HTTP錯誤:404
訪問/ ProjectServlet時出現問題。 原因:
未找到
我認為我正確配置了所有文件,無法解釋為什么Jetty會返回此錯誤。
謝謝你的幫助!
的index.html
<!DOCTYPE html>
<html>
<head>
<meta charset="ISO-8859-1">
<title>TEST</title>
</head>
<body>
<h1>Servlet Call Test:</h1>
<form action="/ProjectServlet" method="GET">
<input type="text" name="name" maxlength="20" value="Name" onfocus="this.select()"/><br>
<input type="submit" name="callservlet" value="Call Servlet."/>
</form>
</body>
</html>
ProjectServlet.java
package servlets;
import java.io.IOException;
import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
/**
* Servlet implementation class ProjectServlet
*/
@WebServlet(description = "Servlet to return JSON response with project list", urlPatterns = { "/ProjectServlet" })
public class ProjectServlet extends HttpServlet {
private static final long serialVersionUID = 1L;
/**
* Default constructor.
*/
public ProjectServlet() {
super();
}
/**
* @see HttpServlet#doGet(HttpServletRequest request, HttpServletResponse response)
*/
protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
//Call Servlet Button
if (request.getParameter("callservlet") != null) {
response.setContentType("application/json");
String name = request.getParameter("name");
String jsonexample = "hi " + name;
response.getWriter().write(jsonexample);
}
}
/**
* @see HttpServlet#doPost(HttpServletRequest request, HttpServletResponse response)
*/
protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
// TODO Auto-generated method stub
}
}
web.xml中
<?xml version="1.0" encoding="UTF-8"?>
<web-app xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns="http://java.sun.com/xml/ns/javaee" xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_3_0.xsd" id="WebApp_ID" version="3.0">
<display-name>Test</display-name>
<welcome-file-list>
<welcome-file>index.html</welcome-file>
<welcome-file>index.htm</welcome-file>
<welcome-file>index.jsp</welcome-file>
<welcome-file>default.html</welcome-file>
<welcome-file>default.htm</welcome-file>
<welcome-file>default.jsp</welcome-file>
</welcome-file-list>
<servlet>
<servlet-name>ProjectServlet</servlet-name>
<servlet-class>servlets.ProjectServlet</servlet-class>
</servlet>
<servlet-mapping>
<servlet-name>ProjectServlet</servlet-name>
<url-pattern>/ProjectServlet</url-pattern>
</servlet-mapping>
</web-app>
這應該如下所示在Servlet url之前添加上下文路徑 。
<form action="${pageContext.servletContext.contextPath}/ProjectServlet"
method="GET">
代替
<form action="/ProjectServlet" method="GET">
使用web.xml
聲明或使用您正在使用的注釋,這就是發生沖突情況和返回404的原因。從xml文件中刪除注釋或映射。
另外,指定提交按鈕的action
<input type="submit" name="callservlet" value="Call Servlet." onClick="action"/>
^^^^^^^^^^^^^^^^^
您需要使用相對路徑(不帶'/'):
<form action="ProjectServlet" method="GET">
或者包含根上下文的servelt的完整路徑:
<form action="/yourRootContext/ProjectServlet" method="GET">
如果您不打算更改根上下文,則可以在頁面中對其進行硬編碼,否則使用以下任一方法獲取:
Scrplet: action="<%= application.getContextPath() %>/ProjectServlet"
EL: action="${pageContext.servletContext.contextPath}/ProjectServlet"
根據您的喜好。
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