struts2-rest-插件失败："org.apache.struts2.dispatcher.Dispatcher - Could not find action or result"

Question

我正在编写一个 REST 服务器，使用 struts2-rest-plugin。我正在使用 SoapUI 和 Postman 测试 REST 调用。我在这里遵循示例代码：

https://cwiki.apache.org/confluence/display/WW/REST+Plugin

我对 controller.index()) 和 controllers.create() 的 REST 调用工作正常。

但是虽然controller.update()成功调用控制器并更新了记录：

19:46:05.361 [http-nio-8080-exec-3] DEBUG com.opensymphony.xwork2.validator.ValidationInterceptor - Validating /contacts with method update.
19:46:05.393 [http-nio-8080-exec-3] DEBUG com.opensymphony.xwork2.DefaultActionInvocation - Executing action method = update
19:46:05.398 [http-nio-8080-exec-3] DEBUG com.opensymphony.xwork2.ognl.SecurityMemberAccess - Checking access for [target: com.example.contactsapp.controllers.ContactsController@7e69160c, member: public java.lang.String com.example.contactsapp.controllers.ContactsController.update(), property: null]
19:46:07.862 [http-nio-8080-exec-3] DEBUG com.example.contactsapp.controllers.ContactsController - Updating existing contact(97)...
...

...它在 "return" 上失败，出现此错误：

...
19:46:11.380 [http-nio-8080-exec-3] WARN  org.apache.struts2.dispatcher.Dispatcher - Could not find action or result: /StrutsContactsApp/contacts/97
com.opensymphony.xwork2.config.ConfigurationException: No result defined for action com.example.contactsapp.controllers.ContactsController and result update
    at org.apache.struts2.rest.RestActionInvocation.findResult(RestActionInvocation.java:283) ~[struts2-rest-plugin-2.5.22.jar:2.5.22]
    at org.apache.struts2.rest.RestActionInvocation.executeResult(RestActionInvocation.java:225) ~[struts2-rest-plugin-2.5.22.jar:2.5.22]
    at org.apache.struts2.rest.RestActionInvocation.processResult(RestActionInvocation.java:189) ~[struts2-rest-plugin-2.5.22.jar:2.5.22]
    at org.apache.struts2.rest.RestActionInvocation.invoke(RestActionInvocation.java:137) ~[struts2-rest-plugin-2.5.22.jar:2.5.22]
    at com.opensymphony.xwork2.DefaultActionProxy.execute(DefaultActionProxy.java:157) ~[struts2-core-2.5.22.jar:2.5.22]
    ...

这是控制器：

public class ContactsController implements ModelDriven<Object> {
    private static final Logger log = LogManager.getLogger(ContactsController.class);
    private String id;
    private Contact model = new Contact();
    private Collection<Contact> list;
    private ContactsRepository contactsRepository = new ContactsRepositoryImpl();

    @Override
    public Object getModel() {
        return (list != null ? list : model);
    }

    public void setId(String id) {
        if (id != null) {
            int contactId = Integer.parseInt(id);
            this.model = contactsRepository.getContact(contactId);
        }
        this.id = id;
    }

    public HttpHeaders index () {
        log.debug("Reading all contacts...");
        list = contactsRepository.getContacts();
        return new DefaultHttpHeaders("index").disableCaching();
    }

   ...
    // PUT /orders/1
    public String update() {
        log.debug("Updating existing contact(" + id + ")...", model);
        contactsRepository.updateContact(model);
        return "update";
    }
    ...

... 和 struts.xml:

<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE struts PUBLIC
        "-//Apache Software Foundation//DTD Struts Configuration 2.5//EN"
        "http://struts.apache.org/dtds/struts-2.5.dtd">
<struts>
    <constant name="struts.mapper.class" value="rest" />
    <constant name="struts.convention.action.suffix" value="Controller"/>
    <constant name="struts.convention.action.mapAllMatches" value="true"/>
    <constant name="struts.convention.default.parent.package" value="rest-default"/>
    <constant name="struts.convention.package.locators" value="controllers"/>

    <package name="contacts" extends="rest-default">
        <global-allowed-methods>index,show,create,update,destroy,deleteConfirm</global-allowed-methods>
    </package>
</struts>

在我添加 <package name="contacts"> 之前没有任何效果。我尝试了几种添加 <action> 和 <result> 的不同变体，但无济于事。

示例网址：

GET Endpoint= http://localhost:8080, Resource= /StrutsContactsApp/contacts.json: 好的
POST Endpoint= http://localhost:8080, Resource= /StrutsContactsApp/contacts.json + JSON body：好的
PUT Endpoint= http://localhost:8080, Resource= http://localhost:8080, + JSON body:

API调用成功，浏览器获取"HTTP 404"；日志显示 "No result defined for action com.example.contactsapp.controllers.ContactsController and result update"

问：对于解决错误和让 "update()" 使用 struts2-rest-plugin 有什么建议吗？

PS: 我在 "update()"、"show()" 和 "destroy()" 这三个方面都遇到了类似的问题。每个人都期望一个 id（我可以在 Eclipse 调试器中看到它被正确传递）。

还有：

struts-rest-plugin 支持像 http://localhost:8080/myapp/contacts.json（对于 JSON）和 http://localhost:8080/myapp/contacts.xml（对于 XML）这样的 URL。我不确定 "update()" 是否需要 contacts.json/id，或者只是 contacts/id。都不起作用:(

Answer 1

好的 - 整个问题是我以 "seemed reasonable" 的方式采用了示例代码。但事实证明 struts2-rest-plugin 有很多我不知道的 "unspoken conventions"。具体来说：

默认情况下，struts2-rest-plugin 映射预先指定的操作名称 index()、show()、create()、update() 和 destroy() 到 CRUD 操作。
我确实 不需要 需要在 struts.xml 中定义 "package" 或任何 "actions"。除非我需要自定义，否则 Struts2-rest-plugin 想要自己管理这些细节。这是（最小的！）struts.xml 我结束了：

我不想使用 .jsp（如示例）。我认为需要从每个动作中 "return something"（如 JSON 响应）。

相反，我只需要重定向到一个动作。例如：

public HttpHeaders create() {
    log.debug("Creating new contact...", model);
    contactsRepository.addContact(model);
    return new DefaultHttpHeaders("index");
    ...

最重要的是，我不清楚 struts2-rest-plugin URI 约定来调用每个不同的 CRUD 操作：

Struts-rest-plugin URL mappings (https://struts.apache.org/plugins/rest/):
**Default**
**Method**   **Description**                                                   **Example**
------    -----------                                                    -------
index()   GET request with no id parameter.                              GET http://localhost:8080/StrutsContactsApp/contacts.json
show()    GET request with an id parameter.                              GET http://localhost:8080/StrutsContactsApp/contacts/1.json
create()  POST request with no id parameter and JSON/XML body.           POST http://localhost:8080/StrutsContactsApp/contacts.json
update()  PUT request with an id parameter and JSON/XML body.            PUT http://localhost:8080/StrutsContactsApp/contacts/65.json
destroy() DELETE request with an id parameter.                           DELETE http://localhost:8080/StrutsContactsApp/contacts/33.json
edit()    GET  request with an id parameter and the edit view specified. 
editNew() GET  request with no id parameter and the new view specified.

Struts-rest-plugin runtime automatically manages:
 - Parsing object ID from REST URI
 - Serializing/deserializing input parameters and return objects
 - By default, controller will implement interface com.opensymphony.xwork2.ModelDriven
 - By default, shouldn't need to (i.e. *shouldn't*) declare any packages or actions in struts.xml
   <= "Follow conventions", and struts2-rest-plugin will manage all the details...

struts2-rest-插件失败："org.apache.struts2.dispatcher.Dispatcher - Could not find action or result"

struts2-rest-plugin failing: "org.apache.struts2.dispatcher.Dispatcher - Could not find action or result"

struts2

struts2-rest-plugin