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      multi/multi_spring-cloud-feign.html
  2. 19
      single/spring-cloud-openfeign.html
  3. 21
      spring-cloud-openfeign.xml

19
multi/multi_spring-cloud-feign.html
Unescape View File

@ -32,10 +32,14 @@ it will resolve the service in the Eureka service registry. If you @@ -32,10 +32,14 @@ it will resolve the service in the Eureka service registry. If you
don’t want to use Eureka, you can simply configure a list of servers
in your external configuration (see
<a class="link" href="">above for example</a>).</p></div><div class="section"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="spring-cloud-feign-overriding-defaults" href="#spring-cloud-feign-overriding-defaults"></a>1.2&nbsp;Overriding Feign Defaults</h2></div></div></div><p>A central concept in Spring Cloud&#8217;s Feign support is that of the named client. Each feign client is part of an ensemble of components that work together to contact a remote server on demand, and the ensemble has a name that you give it as an application developer using the <code class="literal">@FeignClient</code> annotation. Spring Cloud creates a new ensemble as an
<code class="literal">ApplicationContext</code> on demand for each named client using <code class="literal">FeignClientsConfiguration</code>. This contains (amongst other things) an <code class="literal">feign.Decoder</code>, a <code class="literal">feign.Encoder</code>, and a <code class="literal">feign.Contract</code>.</p><p>Spring Cloud lets you take full control of the feign client by declaring additional configuration (on top of the <code class="literal">FeignClientsConfiguration</code>) using <code class="literal">@FeignClient</code>. Example:</p><pre class="programlisting"><em><span class="hl-annotation" style="color: gray">@FeignClient(name = "stores", configuration = FooConfiguration.class)</span></em>
<code class="literal">ApplicationContext</code> on demand for each named client using <code class="literal">FeignClientsConfiguration</code>. This contains (amongst other things) an <code class="literal">feign.Decoder</code>, a <code class="literal">feign.Encoder</code>, and a <code class="literal">feign.Contract</code>.
It is possible to override the name of that ensemble by using the <code class="literal">contextId</code>
attribute of the <code class="literal">@FeignClient</code> annotation.</p><p>Spring Cloud lets you take full control of the feign client by declaring additional configuration (on top of the <code class="literal">FeignClientsConfiguration</code>) using <code class="literal">@FeignClient</code>. Example:</p><pre class="programlisting"><em><span class="hl-annotation" style="color: gray">@FeignClient(name = "stores", configuration = FooConfiguration.class)</span></em>
<span xmlns:d="http://docbook.org/ns/docbook" class="hl-keyword">public</span> <span xmlns:d="http://docbook.org/ns/docbook" class="hl-keyword">interface</span> StoreClient {
<span xmlns:d="http://docbook.org/ns/docbook" class="hl-comment">//..</span>
}</pre><p>In this case the client is composed from the components already in <code class="literal">FeignClientsConfiguration</code> together with any in <code class="literal">FooConfiguration</code> (where the latter will override the former).</p><div class="note" style="margin-left: 0.5in; margin-right: 0.5in;"><table border="0" summary="Note"><tr><td rowspan="2" align="center" valign="top" width="25"><img alt="[Note]" src="images/note.png"></td><th align="left">Note</th></tr><tr><td align="left" valign="top"><p><code class="literal">FooConfiguration</code> does not need to be annotated with <code class="literal">@Configuration</code>. However, if it is, then take care to exclude it from any <code class="literal">@ComponentScan</code> that would otherwise include this configuration as it will become the default source for <code class="literal">feign.Decoder</code>, <code class="literal">feign.Encoder</code>, <code class="literal">feign.Contract</code>, etc., when specified. This can be avoided by putting it in a separate, non-overlapping package from any <code class="literal">@ComponentScan</code> or <code class="literal">@SpringBootApplication</code>, or it can be explicitly excluded in <code class="literal">@ComponentScan</code>.</p></td></tr></table></div><div class="note" style="margin-left: 0.5in; margin-right: 0.5in;"><table border="0" summary="Note"><tr><td rowspan="2" align="center" valign="top" width="25"><img alt="[Note]" src="images/note.png"></td><th align="left">Note</th></tr><tr><td align="left" valign="top"><p>The <code class="literal">serviceId</code> attribute is now deprecated in favor of the <code class="literal">name</code> attribute.</p></td></tr></table></div><div class="warning" style="margin-left: 0.5in; margin-right: 0.5in;"><table border="0" summary="Warning"><tr><td rowspan="2" align="center" valign="top" width="25"><img alt="[Warning]" src="images/warning.png"></td><th align="left">Warning</th></tr><tr><td align="left" valign="top"><p>Previously, using the <code class="literal">url</code> attribute, did not require the <code class="literal">name</code> attribute. Using <code class="literal">name</code> is now required.</p></td></tr></table></div><p>Placeholders are supported in the <code class="literal">name</code> and <code class="literal">url</code> attributes.</p><pre class="programlisting"><em><span class="hl-annotation" style="color: gray">@FeignClient(name = "${feign.name}", url = "${feign.url}")</span></em>
}</pre><p>In this case the client is composed from the components already in <code class="literal">FeignClientsConfiguration</code> together with any in <code class="literal">FooConfiguration</code> (where the latter will override the former).</p><div class="note" style="margin-left: 0.5in; margin-right: 0.5in;"><table border="0" summary="Note"><tr><td rowspan="2" align="center" valign="top" width="25"><img alt="[Note]" src="images/note.png"></td><th align="left">Note</th></tr><tr><td align="left" valign="top"><p><code class="literal">FooConfiguration</code> does not need to be annotated with <code class="literal">@Configuration</code>. However, if it is, then take care to exclude it from any <code class="literal">@ComponentScan</code> that would otherwise include this configuration as it will become the default source for <code class="literal">feign.Decoder</code>, <code class="literal">feign.Encoder</code>, <code class="literal">feign.Contract</code>, etc., when specified. This can be avoided by putting it in a separate, non-overlapping package from any <code class="literal">@ComponentScan</code> or <code class="literal">@SpringBootApplication</code>, or it can be explicitly excluded in <code class="literal">@ComponentScan</code>.</p></td></tr></table></div><div class="note" style="margin-left: 0.5in; margin-right: 0.5in;"><table border="0" summary="Note"><tr><td rowspan="2" align="center" valign="top" width="25"><img alt="[Note]" src="images/note.png"></td><th align="left">Note</th></tr><tr><td align="left" valign="top"><p>The <code class="literal">serviceId</code> attribute is now deprecated in favor of the <code class="literal">name</code> attribute.</p></td></tr></table></div><div class="note" style="margin-left: 0.5in; margin-right: 0.5in;"><table border="0" summary="Note"><tr><td rowspan="2" align="center" valign="top" width="25"><img alt="[Note]" src="images/note.png"></td><th align="left">Note</th></tr><tr><td align="left" valign="top"><p>Using <code class="literal">contextId</code> attribute of the <code class="literal">@FeignClient</code> annotation in addition to changing the name of
the <code class="literal">ApplicationContext</code> ensemble, it will override the alias of the client name
and it will be used as part of the name of the configuration bean created for that client.</p></td></tr></table></div><div class="warning" style="margin-left: 0.5in; margin-right: 0.5in;"><table border="0" summary="Warning"><tr><td rowspan="2" align="center" valign="top" width="25"><img alt="[Warning]" src="images/warning.png"></td><th align="left">Warning</th></tr><tr><td align="left" valign="top"><p>Previously, using the <code class="literal">url</code> attribute, did not require the <code class="literal">name</code> attribute. Using <code class="literal">name</code> is now required.</p></td></tr></table></div><p>Placeholders are supported in the <code class="literal">name</code> and <code class="literal">url</code> attributes.</p><pre class="programlisting"><em><span class="hl-annotation" style="color: gray">@FeignClient(name = "${feign.name}", url = "${feign.url}")</span></em>
<span xmlns:d="http://docbook.org/ns/docbook" class="hl-keyword">public</span> <span xmlns:d="http://docbook.org/ns/docbook" class="hl-keyword">interface</span> StoreClient {
<span xmlns:d="http://docbook.org/ns/docbook" class="hl-comment">//..</span>
}</pre><p>Spring Cloud Netflix provides the following beans by default for feign (<code class="literal">BeanType</code> beanName: <code class="literal">ClassName</code>):</p><div class="itemizedlist"><ul class="itemizedlist" style="list-style-type: disc; "><li class="listitem"><code class="literal">Decoder</code> feignDecoder: <code class="literal">ResponseEntityDecoder</code> (which wraps a <code class="literal">SpringDecoder</code>)</li><li class="listitem"><code class="literal">Encoder</code> feignEncoder: <code class="literal">SpringEncoder</code></li><li class="listitem"><code class="literal">Logger</code> feignLogger: <code class="literal">Slf4jLogger</code></li><li class="listitem"><code class="literal">Contract</code> feignContract: <code class="literal">SpringMvcContract</code></li><li class="listitem"><code class="literal">Feign.Builder</code> feignBuilder: <code class="literal">HystrixFeign.Builder</code></li><li class="listitem"><code class="literal">Client</code> feignClient: if Ribbon is enabled it is a <code class="literal">LoadBalancerFeignClient</code>, otherwise the default feign client is used.</li></ul></div><p>The OkHttpClient and ApacheHttpClient feign clients can be used by setting <code class="literal">feign.okhttp.enabled</code> or <code class="literal">feign.httpclient.enabled</code> to <code class="literal">true</code>, respectively, and having them on the classpath.
@ -85,7 +89,16 @@ thread isolation strategy for Hystrix to `SEMAPHORE</code> or disable Hystrix in @@ -85,7 +89,16 @@ thread isolation strategy for Hystrix to `SEMAPHORE</code> or disable Hystrix in
<span xmlns:d="http://docbook.org/ns/docbook" class="hl-attribute"> default</span>:
<span xmlns:d="http://docbook.org/ns/docbook" class="hl-attribute"> execution</span>:
<span xmlns:d="http://docbook.org/ns/docbook" class="hl-attribute"> isolation</span>:
<span xmlns:d="http://docbook.org/ns/docbook" class="hl-attribute"> strategy</span>: SEMAPHORE</pre></div><div class="section"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="_creating_feign_clients_manually" href="#_creating_feign_clients_manually"></a>1.3&nbsp;Creating Feign Clients Manually</h2></div></div></div><p>In some cases it might be necessary to customize your Feign Clients in a way that is not
<span xmlns:d="http://docbook.org/ns/docbook" class="hl-attribute"> strategy</span>: SEMAPHORE</pre><p>If we want to create multiple feign clients with the same name or url
so that they would point to the same server but each with a different custom configuration then
we have to use <code class="literal">contextId</code> attribute of the <code class="literal">@FeignClient</code> in order to avoid name
collision of these configuration beans.</p><pre class="programlisting"><em><span class="hl-annotation" style="color: gray">@FeignClient(contextId = "fooClient", name = "stores", configuration = FooConfiguration.class)</span></em>
<span xmlns:d="http://docbook.org/ns/docbook" class="hl-keyword">public</span> <span xmlns:d="http://docbook.org/ns/docbook" class="hl-keyword">interface</span> FooClient {
<span xmlns:d="http://docbook.org/ns/docbook" class="hl-comment">//..</span>
}</pre><pre class="programlisting"><em><span class="hl-annotation" style="color: gray">@FeignClient(contextId = "barClient", name = "stores", configuration = BarConfiguration.class)</span></em>
<span xmlns:d="http://docbook.org/ns/docbook" class="hl-keyword">public</span> <span xmlns:d="http://docbook.org/ns/docbook" class="hl-keyword">interface</span> BarClient {
<span xmlns:d="http://docbook.org/ns/docbook" class="hl-comment">//..</span>
}</pre></div><div class="section"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="_creating_feign_clients_manually" href="#_creating_feign_clients_manually"></a>1.3&nbsp;Creating Feign Clients Manually</h2></div></div></div><p>In some cases it might be necessary to customize your Feign Clients in a way that is not
possible using the methods above. In this case you can create Clients using the
<a class="link" href="https://github.com/OpenFeign/feign/#basics" target="_top">Feign Builder API</a>. Below is an example
which creates two Feign Clients with the same interface but configures each one with

19
single/spring-cloud-openfeign.html
Unescape View File

@ -33,10 +33,14 @@ it will resolve the service in the Eureka service registry. If you @@ -33,10 +33,14 @@ it will resolve the service in the Eureka service registry. If you
don&#8217;t want to use Eureka, you can simply configure a list of servers
in your external configuration (see
<a class="link" href="#">above for example</a>).</p></div><div class="section"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="spring-cloud-feign-overriding-defaults" href="#spring-cloud-feign-overriding-defaults"></a>1.2&nbsp;Overriding Feign Defaults</h2></div></div></div><p>A central concept in Spring Cloud&#8217;s Feign support is that of the named client. Each feign client is part of an ensemble of components that work together to contact a remote server on demand, and the ensemble has a name that you give it as an application developer using the <code class="literal">@FeignClient</code> annotation. Spring Cloud creates a new ensemble as an
<code class="literal">ApplicationContext</code> on demand for each named client using <code class="literal">FeignClientsConfiguration</code>. This contains (amongst other things) an <code class="literal">feign.Decoder</code>, a <code class="literal">feign.Encoder</code>, and a <code class="literal">feign.Contract</code>.</p><p>Spring Cloud lets you take full control of the feign client by declaring additional configuration (on top of the <code class="literal">FeignClientsConfiguration</code>) using <code class="literal">@FeignClient</code>. Example:</p><pre class="programlisting"><em><span class="hl-annotation" style="color: gray">@FeignClient(name = "stores", configuration = FooConfiguration.class)</span></em>
<code class="literal">ApplicationContext</code> on demand for each named client using <code class="literal">FeignClientsConfiguration</code>. This contains (amongst other things) an <code class="literal">feign.Decoder</code>, a <code class="literal">feign.Encoder</code>, and a <code class="literal">feign.Contract</code>.
It is possible to override the name of that ensemble by using the <code class="literal">contextId</code>
attribute of the <code class="literal">@FeignClient</code> annotation.</p><p>Spring Cloud lets you take full control of the feign client by declaring additional configuration (on top of the <code class="literal">FeignClientsConfiguration</code>) using <code class="literal">@FeignClient</code>. Example:</p><pre class="programlisting"><em><span class="hl-annotation" style="color: gray">@FeignClient(name = "stores", configuration = FooConfiguration.class)</span></em>
<span xmlns:d="http://docbook.org/ns/docbook" class="hl-keyword">public</span> <span xmlns:d="http://docbook.org/ns/docbook" class="hl-keyword">interface</span> StoreClient {
<span xmlns:d="http://docbook.org/ns/docbook" class="hl-comment">//..</span>
}</pre><p>In this case the client is composed from the components already in <code class="literal">FeignClientsConfiguration</code> together with any in <code class="literal">FooConfiguration</code> (where the latter will override the former).</p><div class="note" style="margin-left: 0.5in; margin-right: 0.5in;"><table border="0" summary="Note"><tr><td rowspan="2" align="center" valign="top" width="25"><img alt="[Note]" src="images/note.png"></td><th align="left">Note</th></tr><tr><td align="left" valign="top"><p><code class="literal">FooConfiguration</code> does not need to be annotated with <code class="literal">@Configuration</code>. However, if it is, then take care to exclude it from any <code class="literal">@ComponentScan</code> that would otherwise include this configuration as it will become the default source for <code class="literal">feign.Decoder</code>, <code class="literal">feign.Encoder</code>, <code class="literal">feign.Contract</code>, etc., when specified. This can be avoided by putting it in a separate, non-overlapping package from any <code class="literal">@ComponentScan</code> or <code class="literal">@SpringBootApplication</code>, or it can be explicitly excluded in <code class="literal">@ComponentScan</code>.</p></td></tr></table></div><div class="note" style="margin-left: 0.5in; margin-right: 0.5in;"><table border="0" summary="Note"><tr><td rowspan="2" align="center" valign="top" width="25"><img alt="[Note]" src="images/note.png"></td><th align="left">Note</th></tr><tr><td align="left" valign="top"><p>The <code class="literal">serviceId</code> attribute is now deprecated in favor of the <code class="literal">name</code> attribute.</p></td></tr></table></div><div class="warning" style="margin-left: 0.5in; margin-right: 0.5in;"><table border="0" summary="Warning"><tr><td rowspan="2" align="center" valign="top" width="25"><img alt="[Warning]" src="images/warning.png"></td><th align="left">Warning</th></tr><tr><td align="left" valign="top"><p>Previously, using the <code class="literal">url</code> attribute, did not require the <code class="literal">name</code> attribute. Using <code class="literal">name</code> is now required.</p></td></tr></table></div><p>Placeholders are supported in the <code class="literal">name</code> and <code class="literal">url</code> attributes.</p><pre class="programlisting"><em><span class="hl-annotation" style="color: gray">@FeignClient(name = "${feign.name}", url = "${feign.url}")</span></em>
}</pre><p>In this case the client is composed from the components already in <code class="literal">FeignClientsConfiguration</code> together with any in <code class="literal">FooConfiguration</code> (where the latter will override the former).</p><div class="note" style="margin-left: 0.5in; margin-right: 0.5in;"><table border="0" summary="Note"><tr><td rowspan="2" align="center" valign="top" width="25"><img alt="[Note]" src="images/note.png"></td><th align="left">Note</th></tr><tr><td align="left" valign="top"><p><code class="literal">FooConfiguration</code> does not need to be annotated with <code class="literal">@Configuration</code>. However, if it is, then take care to exclude it from any <code class="literal">@ComponentScan</code> that would otherwise include this configuration as it will become the default source for <code class="literal">feign.Decoder</code>, <code class="literal">feign.Encoder</code>, <code class="literal">feign.Contract</code>, etc., when specified. This can be avoided by putting it in a separate, non-overlapping package from any <code class="literal">@ComponentScan</code> or <code class="literal">@SpringBootApplication</code>, or it can be explicitly excluded in <code class="literal">@ComponentScan</code>.</p></td></tr></table></div><div class="note" style="margin-left: 0.5in; margin-right: 0.5in;"><table border="0" summary="Note"><tr><td rowspan="2" align="center" valign="top" width="25"><img alt="[Note]" src="images/note.png"></td><th align="left">Note</th></tr><tr><td align="left" valign="top"><p>The <code class="literal">serviceId</code> attribute is now deprecated in favor of the <code class="literal">name</code> attribute.</p></td></tr></table></div><div class="note" style="margin-left: 0.5in; margin-right: 0.5in;"><table border="0" summary="Note"><tr><td rowspan="2" align="center" valign="top" width="25"><img alt="[Note]" src="images/note.png"></td><th align="left">Note</th></tr><tr><td align="left" valign="top"><p>Using <code class="literal">contextId</code> attribute of the <code class="literal">@FeignClient</code> annotation in addition to changing the name of
the <code class="literal">ApplicationContext</code> ensemble, it will override the alias of the client name
and it will be used as part of the name of the configuration bean created for that client.</p></td></tr></table></div><div class="warning" style="margin-left: 0.5in; margin-right: 0.5in;"><table border="0" summary="Warning"><tr><td rowspan="2" align="center" valign="top" width="25"><img alt="[Warning]" src="images/warning.png"></td><th align="left">Warning</th></tr><tr><td align="left" valign="top"><p>Previously, using the <code class="literal">url</code> attribute, did not require the <code class="literal">name</code> attribute. Using <code class="literal">name</code> is now required.</p></td></tr></table></div><p>Placeholders are supported in the <code class="literal">name</code> and <code class="literal">url</code> attributes.</p><pre class="programlisting"><em><span class="hl-annotation" style="color: gray">@FeignClient(name = "${feign.name}", url = "${feign.url}")</span></em>
<span xmlns:d="http://docbook.org/ns/docbook" class="hl-keyword">public</span> <span xmlns:d="http://docbook.org/ns/docbook" class="hl-keyword">interface</span> StoreClient {
<span xmlns:d="http://docbook.org/ns/docbook" class="hl-comment">//..</span>
}</pre><p>Spring Cloud Netflix provides the following beans by default for feign (<code class="literal">BeanType</code> beanName: <code class="literal">ClassName</code>):</p><div class="itemizedlist"><ul class="itemizedlist" style="list-style-type: disc; "><li class="listitem"><code class="literal">Decoder</code> feignDecoder: <code class="literal">ResponseEntityDecoder</code> (which wraps a <code class="literal">SpringDecoder</code>)</li><li class="listitem"><code class="literal">Encoder</code> feignEncoder: <code class="literal">SpringEncoder</code></li><li class="listitem"><code class="literal">Logger</code> feignLogger: <code class="literal">Slf4jLogger</code></li><li class="listitem"><code class="literal">Contract</code> feignContract: <code class="literal">SpringMvcContract</code></li><li class="listitem"><code class="literal">Feign.Builder</code> feignBuilder: <code class="literal">HystrixFeign.Builder</code></li><li class="listitem"><code class="literal">Client</code> feignClient: if Ribbon is enabled it is a <code class="literal">LoadBalancerFeignClient</code>, otherwise the default feign client is used.</li></ul></div><p>The OkHttpClient and ApacheHttpClient feign clients can be used by setting <code class="literal">feign.okhttp.enabled</code> or <code class="literal">feign.httpclient.enabled</code> to <code class="literal">true</code>, respectively, and having them on the classpath.
@ -86,7 +90,16 @@ thread isolation strategy for Hystrix to `SEMAPHORE</code> or disable Hystrix in @@ -86,7 +90,16 @@ thread isolation strategy for Hystrix to `SEMAPHORE</code> or disable Hystrix in
<span xmlns:d="http://docbook.org/ns/docbook" class="hl-attribute"> default</span>:
<span xmlns:d="http://docbook.org/ns/docbook" class="hl-attribute"> execution</span>:
<span xmlns:d="http://docbook.org/ns/docbook" class="hl-attribute"> isolation</span>:
<span xmlns:d="http://docbook.org/ns/docbook" class="hl-attribute"> strategy</span>: SEMAPHORE</pre></div><div class="section"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="_creating_feign_clients_manually" href="#_creating_feign_clients_manually"></a>1.3&nbsp;Creating Feign Clients Manually</h2></div></div></div><p>In some cases it might be necessary to customize your Feign Clients in a way that is not
<span xmlns:d="http://docbook.org/ns/docbook" class="hl-attribute"> strategy</span>: SEMAPHORE</pre><p>If we want to create multiple feign clients with the same name or url
so that they would point to the same server but each with a different custom configuration then
we have to use <code class="literal">contextId</code> attribute of the <code class="literal">@FeignClient</code> in order to avoid name
collision of these configuration beans.</p><pre class="programlisting"><em><span class="hl-annotation" style="color: gray">@FeignClient(contextId = "fooClient", name = "stores", configuration = FooConfiguration.class)</span></em>
<span xmlns:d="http://docbook.org/ns/docbook" class="hl-keyword">public</span> <span xmlns:d="http://docbook.org/ns/docbook" class="hl-keyword">interface</span> FooClient {
<span xmlns:d="http://docbook.org/ns/docbook" class="hl-comment">//..</span>
}</pre><pre class="programlisting"><em><span class="hl-annotation" style="color: gray">@FeignClient(contextId = "barClient", name = "stores", configuration = BarConfiguration.class)</span></em>
<span xmlns:d="http://docbook.org/ns/docbook" class="hl-keyword">public</span> <span xmlns:d="http://docbook.org/ns/docbook" class="hl-keyword">interface</span> BarClient {
<span xmlns:d="http://docbook.org/ns/docbook" class="hl-comment">//..</span>
}</pre></div><div class="section"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="_creating_feign_clients_manually" href="#_creating_feign_clients_manually"></a>1.3&nbsp;Creating Feign Clients Manually</h2></div></div></div><p>In some cases it might be necessary to customize your Feign Clients in a way that is not
possible using the methods above. In this case you can create Clients using the
<a class="link" href="https://github.com/OpenFeign/feign/#basics" target="_top">Feign Builder API</a>. Below is an example
which creates two Feign Clients with the same interface but configures each one with

21
spring-cloud-openfeign.xml
Unescape View File

@ -61,7 +61,9 @@ in your external configuration (see @@ -61,7 +61,9 @@ in your external configuration (see
<section xml:id="spring-cloud-feign-overriding-defaults">
<title>Overriding Feign Defaults</title>
<simpara>A central concept in Spring Cloud&#8217;s Feign support is that of the named client. Each feign client is part of an ensemble of components that work together to contact a remote server on demand, and the ensemble has a name that you give it as an application developer using the <literal>@FeignClient</literal> annotation. Spring Cloud creates a new ensemble as an
<literal>ApplicationContext</literal> on demand for each named client using <literal>FeignClientsConfiguration</literal>. This contains (amongst other things) an <literal>feign.Decoder</literal>, a <literal>feign.Encoder</literal>, and a <literal>feign.Contract</literal>.</simpara>
<literal>ApplicationContext</literal> on demand for each named client using <literal>FeignClientsConfiguration</literal>. This contains (amongst other things) an <literal>feign.Decoder</literal>, a <literal>feign.Encoder</literal>, and a <literal>feign.Contract</literal>.
It is possible to override the name of that ensemble by using the <literal>contextId</literal>
attribute of the <literal>@FeignClient</literal> annotation.</simpara>
<simpara>Spring Cloud lets you take full control of the feign client by declaring additional configuration (on top of the <literal>FeignClientsConfiguration</literal>) using <literal>@FeignClient</literal>. Example:</simpara>
<programlisting language="java" linenumbering="unnumbered">@FeignClient(name = "stores", configuration = FooConfiguration.class)
public interface StoreClient {
@ -74,6 +76,11 @@ public interface StoreClient { @@ -74,6 +76,11 @@ public interface StoreClient {
<note>
<simpara>The <literal>serviceId</literal> attribute is now deprecated in favor of the <literal>name</literal> attribute.</simpara>
</note>
<note>
<simpara>Using <literal>contextId</literal> attribute of the <literal>@FeignClient</literal> annotation in addition to changing the name of
the <literal>ApplicationContext</literal> ensemble, it will override the alias of the client name
and it will be used as part of the name of the configuration bean created for that client.</simpara>
</note>
<warning>
<simpara>Previously, using the <literal>url</literal> attribute, did not require the <literal>name</literal> attribute. Using <literal>name</literal> is now required.</simpara>
</warning>
@ -188,6 +195,18 @@ hystrix: @@ -188,6 +195,18 @@ hystrix:
execution:
isolation:
strategy: SEMAPHORE</programlisting>
<simpara>If we want to create multiple feign clients with the same name or url
so that they would point to the same server but each with a different custom configuration then
we have to use <literal>contextId</literal> attribute of the <literal>@FeignClient</literal> in order to avoid name
collision of these configuration beans.</simpara>
<programlisting language="java" linenumbering="unnumbered">@FeignClient(contextId = "fooClient", name = "stores", configuration = FooConfiguration.class)
public interface FooClient {
//..
}</programlisting>
<programlisting language="java" linenumbering="unnumbered">@FeignClient(contextId = "barClient", name = "stores", configuration = BarConfiguration.class)
public interface BarClient {
//..
}</programlisting>
</section>
<section xml:id="_creating_feign_clients_manually">
<title>Creating Feign Clients Manually</title>

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