struts2核心（二）：xwork/Container/bean/inject

struts2是基于xwork实现的。xwork是一个基于命令模式的通用型框架，独立于Web环境。xwork源自webwork1，而webwork2又基于xwork实现。

xwork入门

需要加入以下包：

跟struts一样，xwork有个默认的配置文件xwork-default.xml，在xwork-core-x.x.x.jar包下：

<!DOCTYPE xwork PUBLIC        "-//Apache Struts//XWork 2.0//EN"        "http://struts.apache.org/dtds/xwork-2.0.dtd"><xwork>    <package name="xwork-default" abstract="true">        <!-- START SNIPPET: xwork2-default-result-types -->        <result-types>            <result-type name="chain" class="com.opensymphony.xwork2.ActionChainResult"/>        </result-types>        <!-- END SNIPPET: xwork2-default-result-types -->        <interceptors>            <!-- START SNIPPET: xwork2-default-interceptors -->            <interceptor name="timer" class="com.opensymphony.xwork2.interceptor.TimerInterceptor"/>            <interceptor name="logger" class="com.opensymphony.xwork2.interceptor.LoggingInterceptor"/>            <interceptor name="chain" class="com.opensymphony.xwork2.interceptor.ChainingInterceptor"/>            <interceptor name="staticParams" class="com.opensymphony.xwork2.interceptor.StaticParametersInterceptor"/>            <interceptor name="params" class="com.opensymphony.xwork2.interceptor.ParametersInterceptor"/>            <interceptor name="filterParams" class="com.opensymphony.xwork2.interceptor.ParameterFilterInterceptor"/>            <interceptor name="removeParams" class="com.opensymphony.xwork2.interceptor.ParameterRemoverInterceptor"/>            <interceptor name="modelDriven" class="com.opensymphony.xwork2.interceptor.ModelDrivenInterceptor"/>            <interceptor name="scopedModelDriven"                         class="com.opensymphony.xwork2.interceptor.ScopedModelDrivenInterceptor"/>            <interceptor name="validation" class="com.opensymphony.xwork2.validator.ValidationInterceptor"/>            <interceptor name="workflow" class="com.opensymphony.xwork2.interceptor.DefaultWorkflowInterceptor"/>            <interceptor name="prepare" class="com.opensymphony.xwork2.interceptor.PrepareInterceptor"/>            <interceptor name="conversionError" class="com.opensymphony.xwork2.interceptor.ConversionErrorInterceptor"/>            <interceptor name="alias" class="com.opensymphony.xwork2.interceptor.AliasInterceptor"/>            <interceptor name="exception" class="com.opensymphony.xwork2.interceptor.ExceptionMappingInterceptor"/>            <interceptor name="i18n" class="com.opensymphony.xwork2.interceptor.I18nInterceptor"/>            <!-- END SNIPPET: xwork2-default-interceptors -->            <!--interceptor name="static-params" class="com.opensymphony.xwork2.interceptor.StaticParametersInterceptor"/>            <interceptor name="filter-params" class="com.opensymphony.xwork2.interceptor.ParameterFilterInterceptor"/>            <interceptor name="remove-params" class="com.opensymphony.xwork2.interceptor.ParameterRemoverInterceptor"/>            <interceptor name="model-driven" class="com.opensymphony.xwork2.interceptor.ModelDrivenInterceptor"/>            <interceptor name="scoped-model-driven"                         class="com.opensymphony.xwork2.interceptor.ScopedModelDrivenInterceptor"/-->            <!-- START SNIPPET: xwork2-default-interceptor-stack -->            <interceptor-stack name="emptyStack"/>            <interceptor-stack name="defaultStack">                <interceptor-ref name="staticParams"/>                <interceptor-ref name="params"/>                <interceptor-ref name="conversionError"/>            </interceptor-stack>            <interceptor-stack name="validationWorkflowStack">                <interceptor-ref name="defaultStack"/>                <interceptor-ref name="validation"/>                <interceptor-ref name="workflow"/>            </interceptor-stack>            <!-- END SNIPPET: xwork2-default-interceptor-stack -->        </interceptors>        <default-class-ref class="com.opensymphony.xwork2.ActionSupport"/>    </package></xwork>

配置了结果类型和拦截器等等。

使用xwork跟使用struts一样，需要开发自己的Action，然后配置在应用程序配置文件xwork.xml中（相当于struts.xml）。配置文件放在类路径下。

下面定义了一个Action：

package org.zzj.action;public class LoginAction {public String login() {return "success";}}

自定义Result：

package org.zzj.action;import com.opensymphony.xwork2.ActionInvocation;import com.opensymphony.xwork2.Result;public class MyResult implements Result {private static final long serialVersionUID = 1L;@Overridepublic void execute(ActionInvocation invocation) throws Exception {System.out.println("MyResult...");}}

配置文件xwork.xml：

<!DOCTYPE xwork PUBLIC"-//OpenSymphonyGroup//XWork1.1.1//EN""xwork-2.3.dtd"><xwork><include file="xwork-default.xml" /><!-- 必须引入，否则无法继承xwork-default --><package name="default" extends="xwork-default"><result-types><result-type name="myResult" class="org.zzj.action.MyResult" /></result-types><action name="login" class="org.zzj.action.LoginAction" method="login"><result name="success" type="myResult" /></action></package></xwork>

注意这里的dtd文件路径一定要正确。我把xwork-core-x.x.x.jar包中的xwork-2.3.dtd文件放到了类路径下。

测试代码：

package org.zzj.action;import java.util.HashMap;import com.opensymphony.xwork2.ActionProxy;import com.opensymphony.xwork2.ActionProxyFactory;import com.opensymphony.xwork2.config.Configuration;import com.opensymphony.xwork2.config.ConfigurationManager;public class Test {static ConfigurationManager cfm = new ConfigurationManager();public static void main(String[] args) throws Exception {Configuration configuration = cfm.getConfiguration();ActionProxyFactory actionProxyFactory = configuration.getContainer().getInstance(ActionProxyFactory.class);ActionProxy actionProxy = actionProxyFactory.createActionProxy("","login", "login", new HashMap<String, Object>());System.out.println(actionProxy.execute());}}

输出：

MyResult...success

Container容器

我们可以在配置文件中配置bean，xwork运行时（加载时）会将bean实例化，并且存放到container中，这样在运行时就可以拿到bean的实例。这是struts插件实现的基础。

自定义一个解码器bean：

package org.zzj.action;import com.opensymphony.xwork2.ObjectFactory;import com.opensymphony.xwork2.inject.Inject;public class Decoder {private ObjectFactory objectFactory;public ObjectFactory getObjectFactory() {return objectFactory;}@Injectpublic void setObjectFactory(ObjectFactory objectFactory) {this.objectFactory = objectFactory;}}

在配置文件的xwork元素下配置该bean：

<bean class="org.zzj.action.Decoder" scope="singleton"/>

关于bean的详细配置可在网上查资料。

测试代码：

package org.zzj.action;import com.opensymphony.xwork2.ObjectFactory;import com.opensymphony.xwork2.config.Configuration;import com.opensymphony.xwork2.config.ConfigurationManager;import com.opensymphony.xwork2.inject.Container;public class TestContainer {static ConfigurationManager cfm = new ConfigurationManager();public static void main(String[] args) {Configuration configuration = cfm.getConfiguration();Container container = configuration.getContainer();System.out.println(container.getInstance(ObjectFactory.class));System.out.println(container.getInstance(Decoder.class));container.inject(Decoder.class);System.out.println(container.getInstance(Decoder.class).getObjectFactory());}}

输出：

[e-mail]@1e13d52com.opensymphony.xwork2.ObjectFactory@5329c5

调用container.inject(Bean.class)方法可以给Bean注入属性（通过注解@inject）。container就是一个IOC容器。

容器的创建是由ContainerBuilder.create()方法完成：

public Container create(boolean loadSingletons) {    ensureNotCreated();    created = true;    final ContainerImpl container = new ContainerImpl(        new HashMap<Key<?>, InternalFactory<?>>(factories));    if (loadSingletons) {      container.callInContext(new ContainerImpl.ContextualCallable<Void>() {        public Void call(InternalContext context) {          for (InternalFactory<?> factory : singletonFactories) {            factory.create(context);          }          return null;        }      });    }    container.injectStatics(staticInjections);    return container;  }