背景

现在各种现代化的浏览器确实惯坏了开发者智能纠错无论是忘记关闭标签甚至重复等等都有可能被chrome这些浏览器智能纠错===》chrome会合并多个body

使用jsp开发的小伙伴新开一个新的组件页面时可能从原先的页面拷贝而来那么里面包含了如下一些

 复制代码

这样造成一个页面从jsp处理完毕后输出的响应流会包含多个

可以参考

问题

多个body对于chrome来说会做自动忽略，那么对于我们使用sitemesh呢？？？

这个问题自然是存在的否则也就不会有这篇博客了！

sitemesh的工作原理很单纯使用filter对响应进行拦截，如果返回的是html那么判断是否需要进行装饰。如果需要找到合适的装饰模板进行装饰并返回新的响应！

代码

对于sitemesh 默认来说会注入规则CoreHtmlTagRuleBundle

public void install(State defaultState, ContentProperty contentProperty, SiteMeshContext siteMeshContext) {        // Core rules for SiteMesh to be functional.        defaultState.addRule("head", new ExportTagToContentRule(siteMeshContext, contentProperty.getChild("head"), false));        defaultState.addRule("title", new ExportTagToContentRule(siteMeshContext, contentProperty.getChild("title"), false));        defaultState.addRule("body", new ExportTagToContentRule(siteMeshContext, contentProperty.getChild("body"), false));        defaultState.addRule("meta", new MetaTagRule(contentProperty.getChild("meta")));             // Ensure that while in 
    
      tag, none of the other rules kick in.        // For example 
     
      
       hello
      
      should not affect the title of the page.        defaultState.addRule("xml", new StateTransitionRule(new State()));    }         public void cleanUp(State defaultState, ContentProperty contentProperty, SiteMeshContext siteMeshContext) {        // In the event that no  tag was captured, use the default buffer contents instead        // (i.e. the whole document, except anything that was written to other buffers).        if (!contentProperty.getChild("body").hasValue()) {            contentProperty.getChild("body").setValue(contentProperty.getValue());        }    }复制代码

从这边可以看出body使用的规则是ExportTagToContentRule

我们细看一下ExportTagToContentRulede的源码

/**     * Exports the contents of a match tag to property of the passed in {
    @link ContentProperty}.     *     * Additionally, if this tag has attributes, they will be written as child properties.     *     * Example
     *     *      * // Java     * myState.addRule("foo", new ExportTagToContentRule(content, "bar");     *     * // Input     * 
     
      hello</foo>     *     * // Exported properties of Content     * bar=hello     * bar.x=1     * bar.b=2     * 
     
     *     * @author Joe Walnes     */    public class ExportTagToContentRule extends BasicBlockRule {             private final ContentProperty targetProperty;        private final boolean includeInContent;        private final SiteMeshContext context;    ;        /**         * @param targetProperty   ContentProperty to export tag contents to.         * @param includeInContent Whether the tag should be included in the content (if false, it will be stripped         *                         from the current ContentProperty that is being written to.         * @see ExportTagToContentRule         */        public ExportTagToContentRule(SiteMeshContext context, ContentProperty targetProperty, boolean includeInContent) {            this.targetProperty = targetProperty;            this.includeInContent = includeInContent;            this.context = context;        }             @Override        protected Object processStart(Tag tag) throws IOException {            // Some terminology:            // Given a tag: '
    
     hello
    '            // INNER contents refers to 'hello'            // OUTER contents refers to '
    
     hello
    '                         Tag t = tag;                 // Export all attributes of the opening tag as child nodes on the target ContentProperty.            for (int i = 0; i < t.getAttributeCount(); i++) {                // attributes of tags using this rule doesn't expand sitemesh:write                // https://github.com/sitemesh/sitemesh3/issues/23                String value = t.getAttributeValue(i);                                 // only if there might be another tag inside the attribute                if(value != null && (value.indexOf('<') < value.indexOf('>'))){                    StringBuilder sb = new StringBuilder();                    context.getContentProcessor().build(CharBuffer.wrap(value), context).getData().writeValueTo(sb);                    value = sb.toString();                                         if(!(t instanceof CustomTag)){                        t = new CustomTag(t);                    }                                           CustomTag custom = (CustomTag) t;                    custom.setAttributeValue(i, value);                                     }                                     targetProperty.getChild(t.getAttributeName(i)).setValue(value);            }                 // Push a buffer for the OUTER contents.            if (!includeInContent) {                // If the tag should NOT be included in the contents, we use a data-only buffer,                // which means that although the contents won't be written                // back to the ContentProperty, they will be available in the main Content data.                // See Content.createDataOnlyBuffer()                tagProcessorContext.pushBuffer(targetProperty.getOwningContent().createDataOnlyBuffer());            } else {                tagProcessorContext.pushBuffer();            }                 // Write opening tag to OUTER buffer.            t.writeTo(tagProcessorContext.currentBuffer());                 // Push a new buffer for storing the INNER contents.            tagProcessorContext.pushBuffer();            return null;        }             @Override        protected void processEnd(Tag tag, Object data) throws IOException {            // Get INNER content, and pop the buffer for INNER contents.            CharSequence innerContent = tagProcessorContext.currentBufferContents();            tagProcessorContext.popBuffer();                 // Write the INNER content and closing tag, to OUTER buffer and pop it.            tagProcessorContext.currentBuffer().append(innerContent);            if (tag.getType() != Tag.Type.EMPTY) { // if the tag is empty we have already written it in processStart().                tag.writeTo(tagProcessorContext.currentBuffer());            }            CharSequence outerContent = tagProcessorContext.currentBufferContents();            tagProcessorContext.popBuffer();                 // Write the OUTER contents to the current buffer, which is now the buffer before the            // tag was processed. Note that if !includeInContent, this buffer will not be written            // to the ContentProperty (though it will be available in Content.getData()).            // See comment in processStart().            tagProcessorContext.currentBuffer().append(outerContent);                 // Export the tag's inner contents to            if (!targetProperty.hasValue()) {                targetProperty.setValue(innerContent);            }        }    }复制代码

可以看到export的最后做了判断为

if (!targetProperty.hasValue()) {               targetProperty.setValue(innerContent);           }复制代码

可以看到当页面上存在多个body标签时sitemesh只会输出第一个body里面的内容！！！

措施

虽然chrome如此智能，虽然我们也不用考虑对其他老旧慢浏览器的支持。但是对于一个合格的后端开发来说

html的输出格式还是要注意的。因此考虑将多余的body删除【大量引入popup的jsp的都包含了一整套的html body】

那么需要清除一些jsp中的多余的body

建议

新建的jsp如果不是页面【是指将会被include其他的jsp中】那么而建议用_打头

比如一个关于左侧导航的可以考虑使用_left.jsp

以_打头的jsp中不允许出现html body 等标签

小问题

有小伙伴发现也有同样的问题么？^_^