eclipse GWT：Servlet URL 映射给出 404 错误
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GWT: Servlet URL mapping gives a 404 error
提问by simchona
I have read the other GWT Servlet questions, but I'm having trouble solving my problem still. My package is called Maps, and it has a service named MyService (which was set up according to a GWT Tutorial). The web.xml file includes the following:
我已经阅读了其他 GWT Servlet 问题，但我仍然无法解决我的问题。我的包名为 Maps，它有一个名为 MyService 的服务（根据 GWT 教程设置）。web.xml 文件包括以下内容：
<servlet>
<servlet-name>MyServiceImpl</servlet-name>
<servlet-class>com.xerox.maps.maps.server.MyServiceImpl</servlet-class>
</servlet>
<servlet-mapping>
<servlet-name>MyServiceImpl</servlet-name>
<url-pattern>/Maps/service</url-pattern>
</servlet-mapping>
In MyService, I have the line:
在 MyService 中，我有一行：
@RemoteServiceRelativePath("service")
public interface MyService extends RemoteService { ...
However, when I try to make an RPC call, there is an error thrown. The details of the error say that it is a 404 HTTP error. How can I fix this, to make sure that the mapping is correct?
但是，当我尝试进行 RPC 调用时，会抛出错误。错误的详细信息说它是 404 HTTP 错误。我该如何解决这个问题，以确保映射正确？
Edit 7.27
编辑 7.27
MyService.java contains the annotation:
MyService.java 包含注释：
@RemoteServiceRelativePath("service")
And web.xml contains:
而 web.xml 包含：
<servlet-name>MyServiceImpl</servlet-name>
<url-pattern>/com.x.maps.Maps/service</url-pattern>
If I follow the XHR with FireBug, it shows me that there is a call to com.x.maps.Maps
如果我使用 FireBug 跟踪 XHR，它会告诉我有一个对 com.x.maps.Maps 的调用
采纳答案by Zasz
404 Not found is thrown usually when service endpoint path is inferred wrongly by GWT. Try removing @RemoteServiceRelativePath("service")and recompile and check, If that does not work find out the URL endpoint of the service manually (by hitting likely paths from a browser till the error changes to 500 internal error) and then give the correct path as argument to @RemoteServiceRelativePath("correct/path"). Few trials I would try right away is @RemoteServiceRelativePath("/Maps/service")and @RemoteServiceRelativePath("Maps/service")without the slash
当 GWT 错误地推断服务端点路径时，通常会抛出 404 Not found。尝试删除@RemoteServiceRelativePath("service")并重新编译并检查，如果这不起作用，手动找出服务的 URL 端点（通过从浏览器点击可能的路径，直到错误更改为 500 内部错误），然后将正确的路径作为参数提供给@RemoteServiceRelativePath("correct/path"). 我会立即尝试的少数试验是@RemoteServiceRelativePath("/Maps/service")并且@RemoteServiceRelativePath("Maps/service")没有斜线
回答by Erel Segal-Halevi
According to this tutorial: https://developers.google.com/web-toolkit/doc/latest/tutorial/RPC
根据本教程：https: //developers.google.com/web-toolkit/doc/latest/tutorial/RPC
The servlet-mapping should be composed of the module "rename-to" and the service "RemoteServiceRelativePath". So, if you have, in your *.gwt.xml file, the following line:
servlet-mapping 应该由模块“rename-to”和服务“RemoteServiceRelativePath”组成。因此，如果您在 *.gwt.xml 文件中有以下行：
<module rename-to='XXX'>
And in your *Service.java file you have the following line:
在您的 *Service.java 文件中，您有以下行：
@RemoteServiceRelativePath("YYY")
Then, in your "web.xml" file, you should have the following lines:
然后，在您的“web.xml”文件中，您应该有以下几行：
<servlet-mapping>
<servlet-name>...servlet-name>
<url-pattern>/XXX/YYY</url-pattern>
</servlet-mapping>
回答by Zasz
New answer after all the comments :
所有评论后的新答案：
Cool, you have made progress! You are hitting this URL -
酷，你进步了！你正在点击这个网址 -
http://127.0.0.1:8888/com.x.maps.maps.Maps
With this POST data I assume - /%7C98544A4AED8C7D42E80C55859E9CEC4C%7Ccom.x.maps.maps.client.MyService%7CreadFile%7Cjava.lang.String/2004016611%7CPrinterList.xls%7C1%7C2%7C3%7C4%7C1%7C5%7C6%7C
有了这个 POST 数据，我假设 - /%7C98544A4AED8C7D42E80C55859E9CEC4C%7Ccom.x.maps.maps.client.MyService%7CreadFile%7Cjava.lang.String/2004016611%7CPrinterList.xls%7C1%7C2%7C3%7C4%7C1%7C5%7C6%7C
This is where the problem is, your servlet is mapped to respond to XHR requests coming to <url-pattern>/Maps/service</url-pattern>but you are hitting /com.x.maps.maps.Mapsinstead. Hence you are getting the 404 path not found status code.
这就是问题所在，您的 servlet 被映射为响应到达的 XHR 请求，<url-pattern>/Maps/service</url-pattern>但您正在点击/com.x.maps.maps.Maps。因此，您将获得 404 路径未找到状态代码。
Alter the url-pattern on the server-side web.xml to match what the browser is making,
OR
Alter the GWT code using the RemoteServiceRelativePath annotation to make the request to /Maps/service instead of to /com.x.maps.maps.Maps
回答by Javier_ts
I have had the same problem but I solved it changing the url-pattern of the Servlet in the web.xml
我遇到了同样的问题，但我通过更改 web.xml 中 Servlet 的 url-pattern 解决了这个问题
Try to put in your web.xml the path to the directory where your GWT javascript module is generated, behind WEB-INF/deploy. in my case:
尝试将生成 GWT javascript 模块的目录的路径放在 web.xml 中，位于 WEB-INF/deploy 后面。就我而言：
<url-pattern>/gwtmodulemain/selection</url-pattern>
You can also rename your module name in your gwt.xml file:
您还可以在 gwt.xml 文件中重命名模块名称：
<module rename-to='gwtmodulemain'>
so you can refer your module from your HTML in this way:
所以你可以通过这种方式从你的 HTML 引用你的模块：
<script type="text/javascript" language="javascript" src="gwtmodulemain/gwtmodulemain.nocache.js"></script>
Good luck!
祝你好运！
