Struts2性能调优拦截器

当我们在工作中需要实现某些小需求时，不妨先进行下简单的调研，看看正在使用的开源框架是否已经具备了我们需要的功能，这样就不用重复发明轮子了。

下面以性能测试为例，看看如何调查Struts2框架是否具备这种功能。

1.struts-default.xml

因为Struts2的许多核心功能都是基于内部拦截器来实现的，所以我们首先要看看它是否有性能调优相关的拦截器。这就需要查看strut2-core-2.3.1.2.jar中的默认配置文件struts-default.xml了。

	<interceptor name="alias" class="com.opensymphony.xwork2.interceptor.AliasInterceptor"/>
            <interceptor name="autowiring" class="com.opensymphony.xwork2.spring.interceptor.ActionAutowiringInterceptor"/>
            <interceptor name="chain" class="com.opensymphony.xwork2.interceptor.ChainingInterceptor"/>
            <interceptor name="conversionError" class="org.apache.struts2.interceptor.StrutsConversionErrorInterceptor"/>
            <interceptor name="cookie" class="org.apache.struts2.interceptor.CookieInterceptor"/>
            <interceptor name="clearSession" class="org.apache.struts2.interceptor.ClearSessionInterceptor" />
            <interceptor name="createSession" class="org.apache.struts2.interceptor.CreateSessionInterceptor" />
            <interceptor name="debugging" class="org.apache.struts2.interceptor.debugging.DebuggingInterceptor" />
            <interceptor name="execAndWait" class="org.apache.struts2.interceptor.ExecuteAndWaitInterceptor"/>
            <interceptorname="exception" class="com.opensymphony.xwork2.interceptor.ExceptionMappingInterceptor"/>
            <interceptor name="fileUpload" class="org.apache.struts2.interceptor.FileUploadInterceptor"/>
            <interceptor name="i18n" class="com.opensymphony.xwork2.interceptor.I18nInterceptor"/>
            <interceptor name="logger" class="com.opensymphony.xwork2.interceptor.LoggingInterceptor"/>
            <interceptor name="modelDriven" class="com.opensymphony.xwork2.interceptor.ModelDrivenInterceptor"/>
            <interceptor name="scopedModelDriven" class="com.opensymphony.xwork2.interceptor.ScopedModelDrivenInterceptor"/>
            <interceptor name="params" class="com.opensymphony.xwork2.interceptor.ParametersInterceptor"/>
            <interceptor name="actionMappingParams" class="org.apache.struts2.interceptor.ActionMappingParametersInteceptor"/>
            <interceptor name="prepare" class="com.opensymphony.xwork2.interceptor.PrepareInterceptor"/>
            <interceptor name="staticParams" class="com.opensymphony.xwork2.interceptor.StaticParametersInterceptor"/>
            <interceptor name="scope" class="org.apache.struts2.interceptor.ScopeInterceptor"/>
            <interceptor name="servletConfig" class="org.apache.struts2.interceptor.ServletConfigInterceptor"/>
            <interceptor name="timer" class="com.opensymphony.xwork2.interceptor.TimerInterceptor"/>
            <interceptor name="token" class="org.apache.struts2.interceptor.TokenInterceptor"/>
            <interceptor name="tokenSession" class="org.apache.struts2.interceptor.TokenSessionStoreInterceptor"/>
            <interceptor name="validation" class="org.apache.struts2.interceptor.validation.AnnotationValidationInterceptor"/>
            <interceptor name="workflow" class="com.opensymphony.xwork2.interceptor.DefaultWorkflowInterceptor"/>
            <interceptor name="store" class="org.apache.struts2.interceptor.MessageStoreInterceptor" />
            <interceptor name="checkbox" class="org.apache.struts2.interceptor.CheckboxInterceptor" />
            <interceptor name="profiling" class="org.apache.struts2.interceptor.ProfilingActivationInterceptor" />
            <interceptor name="roles" class="org.apache.struts2.interceptor.RolesInterceptor" />
            <interceptor name="annotationWorkflow" class="com.opensymphony.xwork2.interceptor.annotations.AnnotationWorkflowInterceptor" />
           <interceptor name="multiselect" class="org.apache.struts2.interceptor.MultiselectInterceptor" />

Struts2像个百宝箱一样内置了很多拦截器，可以看到profiling很可能就是符合我们需求的拦截器，那现在就打开源码一探究竟。

2.ProfilingActivationInterceptor

org.apache.struts2.interceptor.ProfilingActivationInterceptor.java

public class ProfilingActivationInterceptor extendsAbstractInterceptor {
 
    private String profilingKey = "profiling";
    private boolean devMode;
   
    @Inject(StrutsConstants.STRUTS_DEVMODE)
    public void setDevMode(String mode) {
        this.devMode = "true".equals(mode);
    }
 
    @Override
    public String intercept(ActionInvocationinvocation) throws Exception {
        if (devMode) {
            Object val =invocation.getInvocationContext().getParameters().get(profilingKey);
            if (val != null) {
                String sval = (val instanceof String ?(String)val : ((String[])val)[0]);
                boolean enable = "yes".equalsIgnoreCase(sval)|| "true".equalsIgnoreCase(sval);
                UtilTimerStack.setActive(enable);
                invocation.getInvocationContext().getParameters().remove(profilingKey);
            }
        }
        return invocation.invoke();
 
    }
 
}

从源码中可以看到，只要浏览器发过来的HTTP请求参数中包含profiling=true或者yes，性能拦截器就会开启Timer工具类，打印出Action的执行消耗时间。

3.struts.xml

因为profiling拦截器没有包含到默认的defaultStack中，所以我们要先将它追加到我们自定义的拦截器栈中。

<package name="ajax-default" extends="velocity-default">
        <result-types>
            <result-type name="json" class="org.apache.struts2.json.JSONResult"/>
        </result-types>
       
        <interceptors>
            <interceptor-stackname="ajaxInterceptorStack">
            <interceptor-refname="defaultStack" />
            <interceptor-ref name="profiling"/>
            </interceptor-stack>
        </interceptors>
       
        <default-interceptor-refname="ajaxInterceptorStack" />
       
        <global-results>
            <result name="comAjaxResult" type="json">
                <param name="excludeNullProperties">true</param>
                <param name="root">result</param>
                <param name="ignoreHierarchy">false</param>
            </result>
        </global-results>
    </package>

4.userview.js

现在就可以修改AJAX调用参数，追加上profiling参数就可以开始性能调优了。

function searchAllUser(){
    jQuery.ajax({
        type:"post",
        url: "searchAllUser.action",
        processData:true,
        dataType:'json',
        data:jQuery("#userQueryForm").serialize() + "&profiling=yes",
        success:function(data) {
        if (data.status == 1) {
             alert("创建成功");
             generateTableFromJson("result", data.resultRows);
        } else {
             alert("创建失败");
        }
        }
    });
}

5.最终效果

打印结果就是下面这样。除了总执行时间外，Action方法的执行时间和Result的渲染时间都会分别列出。