new-in-3.2.xml

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  <title>New Features and Enhancements in Spring Framework 3.2</title>

  <section xml:id="new-in-3.2-webmvc-async">
    <title>Support for Servlet 3 based asynchronous request processing</title>

    <para>The Spring MVC programming model now provides explicit Servlet 3
    async support. <interfacename>@RequestMapping</interfacename> methods can
    return one of:</para>

    <itemizedlist>
      <listitem>
        <para><interfacename>java.util.concurrent.Callable</interfacename> to
        complete processing in a separate thread managed by a task executor
        within Spring MVC.</para>
      </listitem>

      <listitem>
        <para><classname>org.springframework.web.context.request.async.DeferredResult</classname>
        to complete processing at a later time from a thread not known to
        Spring MVC — for example, in response to some external event (JMS,
        AMQP, etc.)</para>
      </listitem>

      <listitem>
        <para><classname>org.springframework.web.context.request.async.AsyncTask</classname>
        to wrap a <interfacename>Callable</interfacename> and customize the
        timeout value or the task executor to use.</para>
      </listitem>
    </itemizedlist>

    <para>See <xref linkend="mvc-ann-async"/>.</para>

  </section>

  <section xml:id="new-in-3.2-spring-mvc-test">
    <title>Spring MVC Test framework</title>

    <para>First-class support for testing Spring MVC applications with a
    fluent API and without a Servlet container. Server-side tests involve use
    of the <classname>DispatcherServlet</classname> while client-side REST
    tests rely on the <classname>RestTemplate</classname>. See <xref
    linkend="spring-mvc-test-framework" />.</para>
  </section>

  <section xml:id="new-in-3.2-webmvc-content-negotiation">
    <title>Content negotiation improvements</title>

    <para>A <interfacename>ContentNeogtiationStrategy</interfacename> is now
    available for resolving the requested media types from an incoming
    request. The available implementations are based on the file extension,
    query parameter, the 'Accept' header, or a fixed content type.
    Equivalent options were previously available only in the
    ContentNegotiatingViewResolver but are now available throughout.</para>

    <para><classname>ContentNegotiationManager</classname> is the central
    class to use when configuring content negotiation options.
    For more details see <xref linkend="mvc-config-content-negotiation" />.</para>

    <para>The introduction of <classname>ContentNegotiationManger</classname>
    also enables selective suffix pattern matching for incoming requests.
    For more details, see the Javadoc of
    <link
    xl:href="http://static.springsource.org/spring-framework/docs/3.2.0.BUILD-SNAPSHOT/api/org/springframework/web/servlet/mvc/method/annotation/RequestMappingHandlerMapping.html#setUseRegisteredSuffixPatternMatch(boolean)">RequestMappingHandlerMapping.setUseRegisteredSuffixPatternMatch</link>.</para>
  </section>

  <section xml:id="new-in-3.2-webmvc-controller-advice">
    <title><interfacename>@ControllerAdvice</interfacename> annotation</title>

    <para>Classes annotated with
    <interfacename>@ControllerAdvice</interfacename> can contain
    <interfacename>@ExceptionHandler</interfacename>,
    <interfacename>@InitBinder</interfacename>, and
    <interfacename>@ModelAttribute</interfacename> methods and those will
    apply to <interfacename>@RequestMapping</interfacename> methods across
    controller hierarchies as opposed to the controller hierarchy within which
    they are declared. <interfacename>@ControllerAdvice</interfacename> is a
    component annotation allowing implementation classes to be auto-detected
    through classpath scanning.</para>
  </section>

  <section xml:id="new-in-3.2-matrix-variables">
    <title>Matrix variables</title>

    <para>A new <interfacename>@MatrixVariable</interfacename> annotation adds
    support for extracting matrix variables from the request URI. For more
    details see <xref linkend="mvc-ann-matrix-variables" />.</para>
  </section>

  <section xml:id="new-in-3.2-dispatcher-servlet-initializer">
    <title>Abstract base class for code-based Servlet 3+ container
    initialization</title>

    <para>An abstract base class implementation of the
    <interfacename>WebApplicationInitializer</interfacename> interface is
    provided to simplify code-based registration of a DispatcherServlet and
    filters mapped to it. The new class is named
    <classname>AbstractDispatcherServletInitializer</classname> and its
    sub-class
    <classname>AbstractAnnotationConfigDispatcherServletInitializer</classname>
    can be used with Java-based Spring configuration. For more details see
    <xref linkend="mvc-container-config" />.</para>
  </section>

  <section xml:id="new-in-3.2-webmvc-exception-handler-support">
    <title><classname>ResponseEntityExceptionHandler</classname> class</title>

    <para>A convenient base class with an
    <interfacename>@ExceptionHandler</interfacename> method that handles
    standard Spring MVC exceptions and returns a
    <classname>ResponseEntity</classname> that allowing customizing and
    writing the response with HTTP message converters. This servers as an
    alternative to the <classname>DefaultHandlerExceptionResolver</classname>,
    which does the same but returns a <classname>ModelAndView</classname>
    instead.</para>

    <para>See the revised <xref linkend="mvc-exceptionhandlers" /> including
    information on customizing the default Servlet container error
    page.</para>
  </section>

  <section xml:id="new-in-3.2-webmvc-generic-types-rest-template">
    <title>Support for generic types in the
    <classname>RestTemplate</classname> and in
    <interfacename>@RequestBody</interfacename> arguments</title>

    <para>The <classname>RestTemplate</classname> can now read an HTTP
    response to a generic type (e.g. <code>List&lt;Account&gt;</code>). There
    are three new <code>exchange()</code> methods that accept
    <classname>ParameterizedTypeReference</classname>, a new class that
    enables capturing and passing generic type info.</para>

    <para>In support of this feature, the
    <interfacename>HttpMessageConverter</interfacename> is extended by
    <interfacename>GenericHttpMessageConverter</interfacename> adding a method
    for reading content given a specified parameterized type. The new
    interface is implemented by the
    <classname>MappingJacksonHttpMessageConverter</classname> and also by a
    new <classname>Jaxb2CollectionHttpMessageConverter</classname> that can
    read read a generic <interfacename>Collection</interfacename> where the
    generic type is a JAXB type annotated with
    <interfacename>@XmlRootElement</interfacename> or
    <interfacename>@XmlType</interfacename>.</para>
  </section>

  <section xml:id="new-in-3.2-webmvc-jackson-json">
    <title>Jackson JSON 2 and related improvements</title>

    <para>The Jackson JSON 2 library is now supported. Due to packaging
    changes in the Jackson library, there are separate classes in Spring MVC
    as well. Those are
    <classname>MappingJackson2HttpMessageConverter</classname> and
    <classname>MappingJackson2JsonView</classname>. Other related
    configuration improvements include support for pretty printing as well as
    a <classname>JacksonObjectMapperFactoryBean</classname> for convenient
    customization of an <classname>ObjectMapper</classname> in XML
    configuration.</para>
  </section>

  <section xml:id="new-in-3.2-webmvc-request-body-arg-with-binding-result">
    <title><interfacename>@RequestBody</interfacename> improvements</title>

    <para>An <interfacename>@RequestBody</interfacename> or an
    <interfacename>@RequestPart</interfacename> argument can now be followed
    by an <interfacename>Errors</interfacename> argument making it possible to
    handle validation errors (as a result of an
    <interfacename>@Valid</interfacename> annotation) locally within the
    <interfacename>@RequestMapping</interfacename> method.
    <interfacename>@RequestBody</interfacename> now also supports a required
    flag.</para>
  </section>

  <section xml:id="new-in-3.2-webmvc-http-patch">
    <title>HTTP PATCH method</title>

    <para>The HTTP request method <code>PATCH</code> may now be used in
    <interfacename>@RequestMapping</interfacename> methods as well as in the
    <classname>RestTemplate</classname> in conjunction with Apache
    HttpComponents HttpClient version 4.2 or later. The JDK
    <classname>HttpURLConnection</classname> does not support the
    <code>PATCH</code> method.</para>
  </section>

  <section xml:id="new-in-3.2-webmvc-mapped-interceptor-exclude-patterns">
    <title>Excluded patterns in mapped interceptors</title>

    <para>Mapped interceptors now support URL patterns to be excluded. The MVC
    namespace and the MVC JavaConfig both expose these options.</para>
  </section>

  <section xml:id="new-in-3.2-date-time-format-without-joda">
    <title>Support for <interfacename>@DateTimeFormat</interfacename> without
    Joda Time</title>

    <para>The <interfacename>@DateTimeFormat</interfacename> annotation can
    now be used without needing a dependency on the Joda Time library. If Joda
    Time is not present the JDK <classname>SimpleDateFormat</classname> will
    be used to parse and print date patterns. When Joda Time is present it
    will continue to be used in preference to
    <classname>SimpleDateFormat</classname>.</para>
  </section>

  <section xml:id="new-in-3.2-global-date-time-format">
    <title>Global date &amp; time formatting</title>

    <para>It is now possible to define global formats that will be used when
    parsing and printing date and time types. See <xref
    linkend="format-configuring-formatting-globaldatetimeformat" /> for
    details.</para>
  </section>

  <section xml:id="new-in-3.2-testing">
    <title>New Testing Features</title>

    <para>In addition to the aforementioned inclusion of the <link
    linkend="spring-mvc-test-framework">Spring MVC Test Framework</link> in
    the <literal>spring-test</literal> module, the <emphasis>Spring
    TestContext Framework</emphasis> has been revised with support for
    integration testing web applications as well as configuring application
    contexts with context initializers. For further details, consult the
    following.</para>

    <itemizedlist>
      <listitem>
        <para>Configuring and <link
        linkend="testcontext-ctx-management-web">loading a
        WebApplicationContext</link> in integration tests</para>
      </listitem>

      <listitem>
        <para>Testing <link linkend="testcontext-web-scoped-beans">request and
        session scoped beans</link></para>
      </listitem>

      <listitem>
        <para>Improvements to <link linkend="mock-objects-servlet">Servlet API
        mocks</link></para>
      </listitem>

      <listitem>
        <para>Configuring test application contexts with <link
        linkend="testcontext-ctx-management-initializers">ApplicationContextInitializers</link></para>
      </listitem>
    </itemizedlist>

  </section>
</chapter>