如何将Struts约定与tile集成，从而保持约定的好处

Question

如何将Struts约定与Tiles集成在一起，同时保持约定的好处?

问题是约定自动链接url-to-action-to-result，并且在jsp、velocity和freemarker结果中做得很好。它不期望处理tile的结果。

当使用tile时，我们通常希望我们所有的UI操作(与json/xml服务操作相反)都使用tile，但这样做我们就失去了结果组件的约定，需要使用注解。注释允许我们偏离预期，但在大型应用程序中，当期望使用tile时，这是一种烦恼。进一步的约定允许我们仅通过指定视图来创建操作。我们希望在使用瓷砖时也能保持这样的好处。为了纠正这一点，我们需要建立一种将结果传递到瓷砖的约定，这样我们就不需要使用注释将操作绑定到瓷砖结果，并且我们可以继续创建没有操作类的jsp，这将获得约定的好处(没有xml)和瓷砖的好处(所有的锅炉板都被分解成瓷砖)。

如何实现这一点?

这是一个自我回答，帮助那些希望解决这个问题的人

Answer 1

以下是需要的步骤:

• 创建自定义tiles结果，动态构建一个"location"字符串(location字符串是传递给tiles的值)，考虑到命名空间actionName。
• 创建一个使用这个结果的包(命名为"tiles")，并按照惯例使用它作为父包
• 实现并注册一个"com.opensymphony.xwork2"这个步骤是最关键的，因为这个处理程序是在结果无法解析时调用的
• 使用从第一步传入的"location"的tile定义

上述步骤需要在struts.xml

中执行以下操作

<struts>
   <constant name="struts.convention.default.parent.package" value="tiles-package"/>
   <bean type="com.opensymphony.xwork2.UnknownHandler" name="tilesUnknownHandler" class="com.kenmcwilliams.tiles.result.TilesUnknownHandler"/>
   <package  name="tiles-package" extends="convention-default">
      <result-types>
         <result-type default="true" name="tiles" class="com.kenmcwilliams.tiles.result.TilesResult"/>
      </result-types>
   </package>   
</struts>

自定义结果类型实现:

package com.kenmcwilliams.tiles.result;
import com.opensymphony.xwork2.ActionInvocation;
import java.util.logging.Level;
import java.util.logging.Logger;
import javax.servlet.ServletContext;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import org.apache.struts2.ServletActionContext;
import org.apache.struts2.dispatcher.ServletDispatcherResult;
import org.apache.tiles.TilesContainer;
import org.apache.tiles.access.TilesAccess;
import org.apache.tiles.request.ApplicationContext;
import org.apache.tiles.request.servlet.ServletRequest;
import org.apache.tiles.request.servlet.ServletUtil;
public class TilesResult extends ServletDispatcherResult {
    private static final Logger log = Logger.getLogger(TilesResult.class.getName());
    public TilesResult() {
        super();
    }
    public TilesResult(String location) {
        super(location);
    }
    @Override
    public void doExecute(String location, ActionInvocation invocation) throws Exception {
        //location = "test.definition"; //for test
        log.log(Level.INFO, "TilesResult doExecute() location: {0}", location);
        //Start simple conventions
        //
        if (/** tiles && **/location == null) {
            String namespace = invocation.getProxy().getNamespace();
            String actionName = invocation.getProxy().getActionName();
            location = namespace + "#" + actionName + ".jsp"; //Warning forcing extension
            log.log(Level.INFO, "TilesResult namespace: {0}", namespace);
            log.log(Level.INFO, "TilesResult actionName: {0}", actionName);
            log.log(Level.INFO, "TilesResult location: {0}", location);
        }
        //End simple conventions
        setLocation(location);
        ServletContext context = ServletActionContext.getServletContext();
        ApplicationContext applicationContext = ServletUtil.getApplicationContext(context);
        TilesContainer container = TilesAccess.getContainer(applicationContext);
        HttpServletRequest request = ServletActionContext.getRequest();
        HttpServletResponse response = ServletActionContext.getResponse();
        ServletRequest servletRequest = new ServletRequest(applicationContext, request, response);
        container.render(location, servletRequest);
    }
}

TilesUnknownHandler实现:

package com.kenmcwilliams.tiles.result;
import com.opensymphony.xwork2.ActionContext;
import com.opensymphony.xwork2.ObjectFactory;
import com.opensymphony.xwork2.Result;
import com.opensymphony.xwork2.XWorkException;
import com.opensymphony.xwork2.config.Configuration;
import com.opensymphony.xwork2.config.entities.ActionConfig;
import com.opensymphony.xwork2.config.entities.ResultConfig;
import com.opensymphony.xwork2.config.entities.ResultConfig.Builder;
import com.opensymphony.xwork2.inject.Container;
import com.opensymphony.xwork2.inject.Inject;
import flexjson.JSONSerializer;
import java.util.LinkedHashMap;
import java.util.Map;
import java.util.logging.Level;
import java.util.logging.Logger;
import javax.servlet.ServletContext;
import org.apache.commons.lang.StringUtils;
import org.apache.struts2.convention.ConventionUnknownHandler;
public class TilesUnknownHandler extends ConventionUnknownHandler {
    private static final Logger log = Logger.getLogger(TilesUnknownHandler.class.getName());
    private static final String conventionBase = "/WEB-INF/content";
    @Inject
    public TilesUnknownHandler(Configuration configuration, ObjectFactory objectFactory,
            ServletContext servletContext, Container container,
            @Inject("struts.convention.default.parent.package") String defaultParentPackageName,
            @Inject("struts.convention.redirect.to.slash") String redirectToSlash,
            @Inject("struts.convention.action.name.separator") String nameSeparator) {
        super(configuration, objectFactory, servletContext, container, defaultParentPackageName,
                redirectToSlash, nameSeparator);
        log.info("Constructed TilesUnknownHandler");
    }
    @Override
    public ActionConfig handleUnknownAction(String namespace, String actionName)
            throws XWorkException {
        ActionConfig actionConfig;
        log.info("TilesUnknownHandler: before handleUnknownAction");
        ActionConfig handleUnknownAction = super.handleUnknownAction(namespace, actionName);
        log.info("TilesUnknownHandler: after handleUnknownAction, returning with:");
        log.log(Level.INFO, "...ActionConfig value: {0}", (new JSONSerializer().serialize(handleUnknownAction)));
        log.log(Level.INFO, "Modifying handleUnknowAction result handler");
        Map<String, ResultConfig> results = handleUnknownAction.getResults();
        ResultConfig resultConfig = results.get("success");
        Builder builder = new ResultConfig.Builder("com.opensymphony.xwork2.config.entities.ResultConfig", "com.kenmcwilliams.tiles.result.TilesResult");
        Map<String, String> params = resultConfig.getParams();
        String tilesResultString = null;
        String location = params.get("location");
        if (location != null && !location.isEmpty()) {
            int length = conventionBase.length();
            if(StringUtils.startsWith(location, conventionBase)){
                String subString = location.substring(length); //chop off "/WEB-INF/content"
                int count = StringUtils.countMatches(subString, "/");//TODO: maybe check for "//", although I don't know why it would be in the string
                if (count == 1){//empty namespace
                    tilesResultString = subString.replaceFirst("/", "#"); //TODO: because I am doing a straight replacement of the last element the else can probably be removed
                }else{ //replace the last slash between the namespace and the file with "#"
                    int lastIndex = subString.lastIndexOf("/");
                    //subString.substring(lastIndex, lastIndex);
                    String nameSpace = subString.substring(0, lastIndex);
                    String file = subString.substring(lastIndex + 1);
                    tilesResultString = nameSpace + "#" + file;
                }
            }
        }
        Map<String, String> myParams = new LinkedHashMap<String, String>();
        myParams.put("location", tilesResultString);
        builder.addParams(myParams);
        ResultConfig build = builder.build();
        Map<String, ResultConfig> myMap = new LinkedHashMap<String, ResultConfig>();
        myMap.put("success", build);
        log.log(Level.INFO, "nn...results: {0}nn", (new JSONSerializer().serialize(results)));
        actionConfig = new ActionConfig.Builder(handleUnknownAction).addResultConfigs(myMap).build();
        //className("com.kenmcwilliams.tiles.result.TilesResult")
        return actionConfig;
    }
    @Override
    public Result handleUnknownResult(ActionContext actionContext, String actionName,
            ActionConfig actionConfig, String resultCode) throws XWorkException {
        log.info("TilesUnknownHandler: before handleUnknownResult");
        Result handleUnknownResult = super.handleUnknownResult(actionContext, actionName, actionConfig, resultCode);
        log.info("TilesUnknownHandler: after handleUnknownResult, returning with:");
        log.log(Level.INFO, "...Result value: {0}", (new JSONSerializer().serialize(handleUnknownResult)));
        return handleUnknownResult;
    }
}

一个如何使用我们的"location"字符串的例子，它的形式是:NameSpace + "#" + ActionName + ".jsp"，注意下面的<definition name="REGEXP:(.*)#(.*)" extends="default">定义:

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE tiles-definitions PUBLIC "-//Apache Software Foundation//DTD Tiles Configuration 3.0//EN" "http://tiles.apache.org/dtds/tiles-config_3_0.dtd">
<tiles-definitions>
    <definition name="default" template="/WEB-INF/template/template.jsp">
        <put-list-attribute name="cssList" cascade="true">
            <add-attribute value="/style/cssreset-min.css" />
            <add-attribute value="/style/cssfonts-min.css" />
            <add-attribute value="/style/cssbase-min.css" />  
            <add-attribute value="/style/grids-min.css" />
            <add-attribute value="/script/jquery-ui-1.8.24.custom/css/ui-lightness/jquery-ui-1.8.24.custom.css" />
            <add-attribute value="/style/style.css" />
        </put-list-attribute>    
        <put-list-attribute name="jsList" cascade="true">
            <add-attribute value="/script/jquery/1.8.1/jquery.min.js" />
            <add-attribute value="/script/jquery-ui-1.8.24.custom/js/jquery-ui-1.8.24.custom.min.js" />
            <add-attribute value="/script/jquery.sort.js" />
            <add-attribute value="/script/custom/jquery-serialize.js" />
        </put-list-attribute>   
        <put-attribute name="title" value="defaults-name" cascade="true"  type="string"/>
        <put-attribute name="head" value="/WEB-INF/template/head.jsp"/>
        <put-attribute name="header" value="/WEB-INF/template/header.jsp"/>
        <put-attribute name="body" value="/WEB-INF/template/body.jsp"/>
        <put-attribute name="footer" value="/WEB-INF/template/footer.jsp"/>
    </definition>
    <definition name="REGEXP:(.*)#(.*)"  extends="default">
        <put-attribute name="title" cascade="true" expression="OGNL:@com.opensymphony.xwork2.ActionContext@getContext().name"/>
        <put-attribute name="body" value="/WEB-INF/content{1}/{2}"/>
    </definition>
</tiles-definitions>

这样你就可以在/WEB-INF/content/somewhere/my-action.jsp下创建JSP了

就像你使用惯例一样，AND tiles也会适当地修饰它，如果你创建一个名为com.myapp.action.someplace.MyAction的动作类，没有任何结果类型，这段代码将执行，/WEB-INF/content/someplace/my-action.jsp结果仍然会呈现。

你有它的约定+瓷砖没有更多的注释(好为正常情况)。

指出

:

• 这个答案当然不完美，但它确实提供了一个可以应用于其他视图技术(sitemesh，其他)的策略的工作示例。
• 目前，您可以看到"。jsp"被附加在tile结果中，而不是在tile定义中，这是不灵活的。特定的扩展应该在tile中指定，也就是说，定义中的body属性应该附加特定的视图类型(.jsp、.fml、.vm)，因为那时您应该最清楚。
• 重要的是要注意，定义是按照给出的顺序进行尝试的，因此您可以通过在default和REGEXP:(.*)#(.*)定义之间放置定义来覆盖正常情况下的REGEXP:(.*)#(.*)。例如，一个名为authenticated(.*)的定义可以放在这两个定义之间。毕竟，如果你不能做到这一点，所有的页面都必须平铺，我们真的不会使用平铺!
• 就像你知道的，当你使用tiles3 (struts2 tiles3插件)时，你可以使用所有三种类型的视图技术(jsp, freemarker, velocity)来组成一个tile。它的工作原理。您可能会一直使用单一视图技术，但很高兴知道这是可能的。