Controller and Requestmapping

<span id="Label3"></p><p><p><strong>Defining controllers with @controller</strong><br>Spring MVC distributes requests for specific URLs to the controller class for processing<br>In spring 3.0, class is defined as a controller class by @controller Annotations. In order for spring to find a bean defined as a controller, you need to add the following definition in the Spring-context configuration File.</p></p><pre><pre><context:component-scan base-<span style="color: #0000ff;"></span> package</pre></pre><p><p><strong>Use @requestmapping annotations to correlate URLs and controllers</strong><br>With @requestmapping annotations, You can bind a specific URL to a method in a specific controller class or controller class. Such as</p></p><pre><pre><span style="color: #000000;">@Controller @requestmapping (</span>"/helloworld"<span style="color: #000000;">)</span> <span style="color: #0000ff;"></span> public <span style="color: #0000ff;">class</span> <span style="color: #000000;">Helloworld { @RequestMapping (method</span>=<span style="color: #000000;">requestmethod.get) </span>public<span style="color: #0000ff;"></span> <span style="color: #000000;"> Modelandview Hello () { </span><span style="color: #0000ff;">new</span> <span style="color: #000000;"> Modelandview (); Mv.setviewname (</span>"helloworld"<span style="color: #000000;">); </span> <span style="color: #0000ff;">return</span> <span style="color: #000000;">mv; }}</span></pre></pre><p><p>Bind the controller Class/hellowrold and hellowrold, and the @requestmapping (method=requestmethod.get) before the Hello () method will be the Hello method and/ The GET request of the hellorworld.action is bound together.</p></p><p><p><strong>Define Multiaction Controllers</strong><br>Use a controller to handle multiple actions, called Multiaction Controllers. @RequestMapping annotations are not required to be placed before the class definition, but can be used directly as a label for a method level, and when used, the Contorller class becomes a multiaction controller, such as</p></p><pre><span style="color: #000000;"><span style="color: #000000;">@Controller</span></span><span style="color: #0000ff;"><span style="color: #0000ff;"></span> public</span> <span style="color: #0000ff;"><span style="color: #0000ff;">class</span></span><span style="color: #000000;"><span style="color: #000000;">Multiactionhelloworld {@RequestMapping (</span></span>"/hello1"<span style="color: #000000;"><span style="color: #000000;">) </span></span><span style="color: #0000ff;"><span style="color: #0000ff;"></span> public</span><span style="color: #000000;"><span style="color: #000000;">modelandview hello1 () {modelandview mv</span></span>=<span style="color: #0000ff;"><span style="color: #0000ff;">New</span></span><span style="color: #000000;"><span style="color: #000000;">Modelandview (); Mv.setviewname (</span></span>"helloworld"<span style="color: #000000;"><span style="color: #000000;">); </span></span><span style="color: #0000ff;"><span style="color: #0000ff;">return</span></span><span style="color: #000000;"><span style="color: #000000;">mv; } @RequestMapping (</span></span>"/hello2"<span style="color: #000000;"><span style="color: #000000;">) </span></span><span style="color: #0000ff;"><span style="color: #0000ff;"></span> public</span><span style="color: #000000;"><span style="color: #000000;">modelandview Hello2 () {modelandview mv</span></span>=<span style="color: #0000ff;"><span style="color: #0000ff;">New</span></span><span style="color: #000000;"><span style="color: #000000;">Modelandview (); Mv.setviewname (</span></span>"helloworld"<span style="color: #000000;"><span style="color: #000000;">); </span></span><span style="color: #0000ff;"><span style="color: #0000ff;">return</span></span><span style="color: #000000;"><span style="color: #000000;">mv; }</span></span></pre><p><p>The two methods Hello1 and Hello2 are defined here respectively, and the corresponding URLs are/hello1 And/hello2</p></p><p><p></p></p><p><p><strong>URL Template</strong><br>The URL in the @requestmapping parameter, in addition to the regular url, can use the URL template to define a URL that forms a similar rest request.<br>For example</p></p><pre><pre> @RequestMapping ("/urltemplate/{username}" <span style="color: #000000;">) </span> <span style="color: #0000ff;">public </span> <span style="color: #000000;"> Modelandview test1 (@PathVariable String username) {modelandview mv = <span style="color: #0000ff;">new </span> <span style="color: #000000;"> Modelandview (); Mv.addobject (</span> "userName" <span style="color: #000000;">, userName); System.out.println (username); Mv.setviewname (</span> "test002" <span style="color: #000000;">); </span> <span style="color: #0000ff;">return </span> <span style="color: #000000;"> mv; } </span> <span style= "white-space:normal;" ></span> </span></pre></pre><p><p>The above is bound with the values of {username} and {userid} in the request url, respectively, by @pathvariable the username and userid in the incoming parameter<br><br><strong>Optional parameters for @requestmapping</strong><br><strong>value</strong>: Represents the format of the URL that needs to be matched.<br><strong>method</strong>: Represents the HTTP protocol required to process the request (such as get,post,put,delete, etc.), and the optional value is the value of the enum REQUESTMETHOD.<br><strong>params</strong>: The format is "paramname=paramvalue" or "paramname!=paramvalue". Without parameters, the paramvalue can be any Value.<br>such as params = {"param1=1", "param2!=2", "param3"}, The corresponding URL must include PARAM1,PARAM2,PARAM3 three parameters, where the value of param1 must be 1,PARAM2 value cannot be 2, The value of the PARAM3 can be any Value.<br><strong>headers</strong>: The content that must be included in the headers that is used to qualify the corresponding reqeust request, such as<br>headers={"connection=keep-alive"}, which indicates that the value of Connection in the request header must be Keep-alive.</p></p><p><p></p></p><p><p>Controller and Requestmapping</p></p></span>