Question

// web.xml    
<?xml version="1.0" encoding="UTF-8"?>
    <web-app xmlns="http://xmlns.jcp.org/xml/ns/javaee"
             xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
             xsi:schemaLocation="http://xmlns.jcp.org/xml/ns/javaee http://xmlns.jcp.org/xml/ns/javaee/web-app_3_1.xsd"
             version="3.1">

        <servlet>
            <servlet-name>welcome</servlet-name>
            <servlet-class>com.rippleworks.WelcomeServlet</servlet-class>
        </servlet>

        <servlet-mapping>
            <servlet-name>welcome</servlet-name>
            <url-pattern>/welcome</url-pattern>
        </servlet-mapping>
    </web-app>

// WelcomeServlet.java

package com.rippleworks;

import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;
import java.io.PrintStream;

public class WelcomeServlet extends HttpServlet {
    @Override
    protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        super.doGet(req, resp);
        PrintStream out = new PrintStream(resp.getOutputStream());
        out.println("Hello students!");
    }
}

// index.jsp

<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<html>
<head>
    <title>Title</title>
</head>
<body>
    <h1>HEllo world!</h1>
</body>
</html>

我已将Intellij配置为使用本地tomcat安装。当我部署我的项目时，只有index.jsp似乎工作。对/ welcome路径的http请求给出了405.我做错了什么？

Answer 1

servlet映射似乎错误..执行以下操作：

  <servlet>
    <servlet-name>WelcomeServlet</servlet-name>
    <servlet-class>com.rippleworks.WelcomeServlet</servlet-class>
  </servlet>
  <servlet-mapping>
    <servlet-name>WelcomeServlet</servlet-name>
    <url-pattern>/welcome</url-pattern>
  </servlet-mapping>

你的servlet：

public class WelcomeServlet extends HttpServlet {

    protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {

    //do whatever you want here


    //forward request to index
    RequestDispatcher rd=req.getRequestDispatcher("index.jsp");    
    rd.forward(req,resp);  

    }
}

尝试一下，让我知道它是否适合你。请记住在尝试之前重新启动服务器。

Answer 2

导致问题的是super.doGet（..）。从源代码 HttpServlet，默认实现是这个，

public void doGet(..) {
        String protocol = req.getProtocol();
        String msg = lStrings.getString("http.method_get_not_supported");
        if (protocol.endsWith("1.1")) {
            resp.sendError(405, msg);
        } else {
            resp.sendError(400, msg);
        }
}

它始终会回复错误。删除了对super方法的调用，现在工作正常。

PS。感谢大家的回复。

使用tomcat服务器8.5

2 个答案: