提交 e9ac4bc0 编写于 作者: A Arjen Poutsma

Moved REST HTTP Method Conversion to View chapter.

上级 06777c81
......@@ -38,50 +38,6 @@
configuration</link> to understand the general programming model.</para>
</section>
<section id="rest-method-conversion">
<title>HTTP Method Conversion</title>
<para>A key principle of REST is the use of the Uniform Interface. This
means that all resources (URLs) can be manipulated using the same four
HTTP methods: GET, PUT, POST, and DELETE. For each methods, the HTTP
specification defines the exact semantics. For instance, a GET should
always be a safe operation, meaning that is has no side effects, and a
PUT or DELETE should be idempotent, meaning that you can repeat these
operations over and over again, but the end result should be the same.
While HTTP defines these four methods, HTML only supports two: GET and
POST. Fortunately, there are two possible workarounds: you can either
use JavaScript to do your PUT or DELETE, or simply do a POST with the
'real' method as an additional parameter (modeled as a hidden input
field in an HTML form). This latter trick is what Spring's
<classname>HiddenHttpMethodFilter</classname> does. This filter is a
plain Servlet Filter and therefore it can be used in combination with
any web framework (not just Spring MVC). Simply add this filter to your
web.xml, and a POST with a hidden _method parameter will be converted
into the corresponding HTTP method request.</para>
<section id="rest-form-tags">
<title>Supporting Spring form tags</title>
<para>To support HTTP method conversion the Spring MVC form tag was
updated to support setting the HTTP method. For example, the following
snippet taken from the updated Petclinic sample</para>
<programlisting language="xml">&lt;form:form method="delete"&gt;
&lt;p class="submit"&gt;&lt;input type="submit" value="Delete Pet"/&gt;&lt;/p&gt;
&lt;/form:form&gt;</programlisting>
<para>This will actually perform an HTTP POST, with the 'real' DELETE
method hidden behind a request parameter, to be picked up by the
<classname>HiddenHttpMethodFilter</classname>. The corresponding
@Controller method is shown below</para>
<programlisting language="java">@RequestMapping(method = RequestMethod.DELETE)
public String deletePet(@PathVariable int ownerId, @PathVariable int petId) {
this.clinic.deletePet(petId);
return "redirect:/owners/" + ownerId;
}</programlisting>
</section>
</section>
<section id="rest-etag">
<title>ETag support</title>
......
......@@ -737,6 +737,57 @@ productList.url=/WEB-INF/jsp/productlist.jsp</programlisting>
&lt;/tr&gt;
&lt;/form&gt;</programlisting>
</section>
<section id="rest-method-conversion">
<title>HTTP Method Conversion</title>
<para>A key principle of REST is the use of the Uniform Interface.
This means that all resources (URLs) can be manipulated using the same
four HTTP methods: GET, PUT, POST, and DELETE. For each methods, the
HTTP specification defines the exact semantics. For instance, a GET
should always be a safe operation, meaning that is has no side
effects, and a PUT or DELETE should be idempotent, meaning that you
can repeat these operations over and over again, but the end result
should be the same. While HTTP defines these four methods, HTML only
supports two: GET and POST. Fortunately, there are two possible
workarounds: you can either use JavaScript to do your PUT or DELETE,
or simply do a POST with the 'real' method as an additional parameter
(modeled as a hidden input field in an HTML form). This latter trick
is what Spring's <classname>HiddenHttpMethodFilter</classname> does.
This filter is a plain Servlet Filter and therefore it can be used in
combination with any web framework (not just Spring MVC). Simply add
this filter to your web.xml, and a POST with a hidden _method
parameter will be converted into the corresponding HTTP method
request.</para>
<para>To support HTTP method conversion the Spring MVC form tag was
updated to support setting the HTTP method. For example, the following
snippet taken from the updated Petclinic sample</para>
<programlisting language="xml">&lt;form:form method="delete"&gt;
&lt;p class="submit"&gt;&lt;input type="submit" value="Delete Pet"/&gt;&lt;/p&gt;
&lt;/form:form&gt;</programlisting>
<para>This will actually perform an HTTP POST, with the 'real' DELETE
method hidden behind a request parameter, to be picked up by the
<classname>HiddenHttpMethodFilter</classname>, as defined in web.xml:</para>
<programlisting language="java">&lt;filter&gt;
&lt;filter-name&gt;httpMethodFilter&lt;/filter-name&gt;
&lt;filter-class&gt;org.springframework.web.filter.HiddenHttpMethodFilter&lt;/filter-class&gt;
&lt;/filter&gt;
&lt;filter-mapping&gt;
&lt;filter-name&gt;httpMethodFilter&lt;/filter-name&gt;
&lt;servlet-name&gt;petclinic&lt;/servlet-name&gt;
&lt;/filter-mapping&gt;</programlisting><para>The corresponding @Controller method
is shown below:</para>
<programlisting language="java">@RequestMapping(method = RequestMethod.DELETE)
public String deletePet(@PathVariable int ownerId, @PathVariable int petId) {
this.clinic.deletePet(petId);
return "redirect:/owners/" + ownerId;
}</programlisting>
</section>
</section>
</section>
......@@ -2435,7 +2486,7 @@ simpleReport.reportDataKey=myBeanData</programlisting>
</section>
</section>
<section id="rest-feedview">
<section id="view-feeds">
<title>Feed Views</title>
<para>Both <classname>AbstractAtomFeedView</classname> and
......
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