Struts2-Tiles 2.5.2 升级指南和通配符拓展

﹏ヽ暗。殇╰゛Y 2022-07-17 03:47 130阅读 0赞

最近工程从Struts2.3.18升级Struts2.5.2导致相关联的插件都需要升级到相同版本，其中tiles的变化最大。  
1、web.xml上

*  listener

org.apache.struts2.tiles.StrutsTilesListener

*  context-param

新增tiles资源位置定义参数：org.apache.tiles.definition.DefinitionsFactory.DEFINITIONS_CONFIG

2、tiles.xml 资源声明改成使用value指定！！

由：
    <definition name="web.standard.layout.witherror" template="layout.jsp">
     <put-attribute name="header">header.jsp</put-attribute
    </definition>
    改为：
    <definition name="web.standard.layout.witherror" template="layout.jsp">
            <put-attribute name="header" value="header.jsp"></put-attribute
        </definition>

3、默认会加载/WEB-INF/tiles.xml

这样tiles升级基本完成。

--------------------

下面介绍自定义tiles资源搜索功能：  
从org.apache.struts2.tiles.StrutsTilesInitializer源码：

@Override
        protected ApplicationContext createTilesApplicationContext(ApplicationContext preliminaryContext) {
            ServletContext servletContext = (ServletContext) preliminaryContext.getContext();
    
            if (servletContext.getInitParameter(DefinitionsFactory.DEFINITIONS_CONFIG) != null) {
                LOG.trace("Found definitions config in web.xml, using standard Servlet support ....");
                return new ServletApplicationContext(servletContext);
            } else {
                LOG.trace("Initializing Tiles wildcard support ...");
                return new StrutsWildcardServletApplicationContext(servletContext);
            }
        }

上可得知当在web.xml上自定义了tiles的资源文件位置的话使用ServletApplicationContext进行资源文件的查找。但是一般工程都是使用通配符的形式或者使用spring的文件路径定义的方式配置文件，例如：

> file:/WEB-INF/tiles.xml,classpath:/com/cml/test/*\*/resource/*.tiles.xml

此时需要自己拓展了，使用spring的ResourcePatternResolver进行资源查找。  
1、第一步，自定义listener

public class WildcardTilesListener extends AbstractTilesListener { 
    
        private static final Logger LOG = LogManager.getLogger(WildcardTilesListener.class);
    
        @Override
        protected TilesInitializer createTilesInitializer() {
            LOG.info("Starting Struts Tiles 3 integration ...");
            return new WildcardInitializer();
        }
    
    }

2、第二步 自定义StrutsTilesInitializer

public class WildcardInitializer extends StrutsTilesInitializer { 
        private static final Logger LOG = LogManager.getLogger(WildcardInitializer.class);
    
        @Override
        protected ApplicationContext createTilesApplicationContext(ApplicationContext preliminaryContext) {
            ServletContext servletContext = (ServletContext) preliminaryContext.getContext();
            return new WildcardApplicationContext(servletContext);
        }
    
        @Override
        protected AbstractTilesContainerFactory createContainerFactory(ApplicationContext context) {
            LOG.trace("Creating dedicated Struts factory to create Tiles container");
            return new StrutsTilesContainerFactory();
        }
    
    }

将tiles文件搜索的ApplicationContext更改为自定义的WildcardApplicationContext  
3、第三步 继承ServletApplicationContext实现通配符资源文件搜索

public class WildcardApplicationContext extends ServletApplicationContext { 
    
        private static final Logger LOG = LogManager.getLogger(StrutsWildcardServletApplicationContext.class);
    
        private ServletContext context;
    
        public WildcardApplicationContext(ServletContext context) {
            super(context);
            this.context = context;
        }
    
        public Collection<ApplicationResource> getResources(String path) {
            Set<ApplicationResource> resources = new HashSet<>();
    
            if (path.startsWith("/")) {
                LOG.trace("Using ServletContext to load resource {}", path);
                ApplicationResource resource = getResource(path);
                if (resource != null) {
                    resources.add(resource);
                }
            }
    
            try {
                resources.addAll(findResources(path));
            } catch (IOException e) {
                LOG.error("Cannot find resources for [{}]", path, e);
            }
    
            return resources;
        }
    
        public ApplicationResource getResource(ApplicationResource base, Locale locale) {
            String localePath = base.getLocalePath(locale);
            if (new File(localePath).exists()) {
                try {
                    return new StrutsApplicationResource(URI.create("file://" + localePath).toURL());
                } catch (MalformedURLException e) {
                    LOG.warn("Cannot access [{}]", localePath, e);
                    return null;
                }
            }
            return null;
        }
    
        protected Set<ApplicationResource> findResources(String path) throws IOException {
            Set<ApplicationResource> resources = new HashSet<>();
    
            LOG.trace("Using ResourceFinder to find matches for {}", path);
    
            Set<URL> matches = find(path);
    
            LOG.trace("Found resources {} matching pattern {}", matches, path);
    
            Iterator<URL> it = matches.iterator();
            while (it.hasNext()) {
                resources.add(new StrutsApplicationResource(it.next()));
            }
    
            LOG.trace("Found resources {} for path {}", resources, path);
            return resources;
        }
    
        protected Set<URL> find(String patternResource) {
    
            Set<URL> pathResources = new HashSet<>();
    
            try {
                ResourcePatternResolver rpResolver = new PathMatchingResourcePatternResolver();
    
                Resource[] resources = rpResolver.getResources(patternResource);
                // FileSystemResource ClasspathContextResource
                for (Resource resource : resources) {
    
                    URL resourceUrl = null;
    
                    if (resource instanceof UrlResource) {
                        resourceUrl = context.getResource(resource.getFile().toString());
                    } else if (resource instanceof ClassPathResource) {
                        ClassPathResource classpathRes = (ClassPathResource) resource;
                        resourceUrl = context.getResource(classpathRes.getPath());
                    } else {
                        resourceUrl = resource.getURL();
                    }
    
                    if (resourceUrl != null) {
                        if (LOG.isDebugEnabled()) {
                            LOG.debug("Adding resource '" + resourceUrl + "' to definitions factory.");
                        }
                        pathResources.add(resourceUrl);
                        // pathResources.put(resourceUrl.toString(), resourceUrl);
                    } else {
                        LOG.warn("Unable to find configured definition '" + resource + "'");
                    }
                }
            } catch (IOException e) {
                LOG.error("<<<<<find>>>>", e);
            }
    
            return pathResources;
        }
    
    }

这样就可以使用spring的配置文件路径的方式配置tiles资源文件了，满足通配符。

4、最后一步 在web.xml上配置tiles文件的位置和listener,自动搜索工程resoruce/\*.tiles.xml文件

<context-param>
            <param-name>org.apache.tiles.definition.DefinitionsFactory.DEFINITIONS_CONFIG</param-name>
            <param-value>file:/WEB-INF/tiles.xml,classpath:/com/cml/tile/**/resource/*.tiles.xml</param-value>
        </context-param>
    
    
        <listener>
            <listener-class>xxx.x..x.WildcardTilesListener</listener-class>
        </listener>

由此，Struts-Tiles 2.5.2升级配置完成。