<!DOCTYPE html>
<!-- [if IE 8]><html class="no - js lt - ie9" lang="zh - CN" > <![endif] -->
<!-- [if gt IE 8]><! --> < html class = "no-js" lang = "zh-CN" > <!-- <![endif] -->
< head >
< meta charset = "utf-8" >
< meta name = "viewport" content = "width=device-width, initial-scale=1.0" >
< title > 表达式核心变量 — Arthas 3.3.2 文档< / title >
< link rel = "shortcut icon" href = "_static/favicon.ico" / >
< script type = "text/javascript" src = "_static/js/modernizr.min.js" > < / script >
< script type = "text/javascript" id = "documentation_options" data-url_root = "./" src = "_static/documentation_options.js" > < / script >
< script type = "text/javascript" src = "_static/jquery.js" > < / script >
< script type = "text/javascript" src = "_static/underscore.js" > < / script >
< script type = "text/javascript" src = "_static/doctools.js" > < / script >
< script type = "text/javascript" src = "_static/language_data.js" > < / script >
< script type = "text/javascript" src = "_static/translations.js" > < / script >
< script type = "text/javascript" src = "_static/js/theme.js" > < / script >
< link rel = "stylesheet" href = "_static/css/theme.css" type = "text/css" / >
< link rel = "stylesheet" href = "_static/pygments.css" type = "text/css" / >
< link rel = "stylesheet" href = "_static/overrides.css" type = "text/css" / >
< link rel = "index" title = "索引" href = "genindex.html" / >
< link rel = "search" title = "搜索" href = "search.html" / >
< script src = "_static/center_page.js" > < / script >
< link rel = "stylesheet" href = "https://cdnjs.cloudflare.com/ajax/libs/highlight.js/9.13.1/styles/github.min.css" >
< / head >
< body class = "wy-body-for-nav" >
< div class = "wy-grid-for-nav" >
< nav data-toggle = "wy-nav-shift" class = "wy-nav-side" >
< div class = "wy-side-scroll" >
< div class = "wy-side-nav-search" >
< a href = "index.html" class = "icon icon-home" > Arthas
< / a >
< div class = "version" >
3.3.2
< / div >
< div role = "search" >
< form id = "rtd-search-form" class = "wy-form" action = "search.html" method = "get" >
< input type = "text" name = "q" placeholder = "Search docs" / >
< input type = "hidden" name = "check_keywords" value = "yes" / >
< input type = "hidden" name = "area" value = "default" / >
< / form >
< / div >
< / div >
< div class = "wy-menu wy-menu-vertical" data-spy = "affix" role = "navigation" aria-label = "main navigation" >
< ul >
< li class = "toctree-l1" > < a class = "reference external" href = "https://mp.weixin.qq.com/s/677GO-3kYx5ygG9rlOlfQg" > 招聘信息< / a > < / li >
< li class = "toctree-l1" > < a class = "reference external" href = "https://alibaba.github.io/arthas/en/" > English Docs< / a > < / li >
< li class = "toctree-l1" > < a class = "reference external" href = "https://alibaba.github.io/arthas/arthas-tutorials?language=cn" > 在线教程(推荐)< / a > < / li >
< li class = "toctree-l1" > < a class = "reference internal" href = "install-detail.html" > 安装< / a > < / li >
< li class = "toctree-l1" > < a class = "reference internal" href = "download.html" > 下载< / a > < / li >
< li class = "toctree-l1" > < a class = "reference internal" href = "quick-start.html" > 快速入门< / a > < / li >
< li class = "toctree-l1" > < a class = "reference internal" href = "advanced-use.html" > 进阶使用< / a > < / li >
< li class = "toctree-l1" > < a class = "reference internal" href = "commands.html" > 命令列表< / a > < / li >
< li class = "toctree-l1" > < a class = "reference internal" href = "web-console.html" > WebConsole< / a > < / li >
< li class = "toctree-l1" > < a class = "reference internal" href = "docker.html" > Docker< / a > < / li >
< li class = "toctree-l1" > < a class = "reference external" href = "https://github.com/alibaba/arthas/issues?q=label%3Auser-case" > 用户案例< / a > < / li >
< li class = "toctree-l1" > < a class = "reference external" href = "https://github.com/alibaba/arthas/issues?q=label%3Aquestion-answered" > 常见问题< / a > < / li >
< li class = "toctree-l1" > < a class = "reference external" href = "https://github.com/alibaba/arthas" > Fork me at GitHub< / a > < / li >
< li class = "toctree-l1" > < a class = "reference external" href = "https://github.com/alibaba/arthas/blob/master/CONTRIBUTING.md#" > 编译调试/参与贡献< / a > < / li >
< li class = "toctree-l1" > < a class = "reference external" href = "https://github.com/alibaba/arthas/releases" > Release Notes< / a > < / li >
< li class = "toctree-l1" > < a class = "reference internal" href = "contact-us.html" > QQ群/钉钉群< / a > < / li >
< li class = "toctree-l1" > < a class = "reference external" href = "https://arthas.gitee.io/" > 国内镜像站< / a > < / li >
< / ul >
< / div >
< / div >
< / nav >
< section data-toggle = "wy-nav-shift" class = "wy-nav-content-wrap" >
< nav class = "wy-nav-top" aria-label = "top navigation" >
< i data-toggle = "wy-nav-top" class = "fa fa-bars" > < / i >
< a href = "index.html" > Arthas< / a >
< / nav >
< div class = "wy-nav-content" >
< div class = "rst-content" >
< div role = "navigation" aria-label = "breadcrumbs navigation" >
< ul class = "wy-breadcrumbs" >
< li > < a href = "index.html" > Docs< / a > » < / li >
< li > 表达式核心变量< / li >
< li class = "wy-breadcrumbs-aside" >
< a href = "https://github.com/alibaba/arthas/blob/master/site/src/site/sphinx/advice-class.md" class = "fa fa-github" > Edit on GitHub< / a >
< / li >
< / ul >
< hr / >
< / div >
< div role = "main" class = "document" itemscope = "itemscope" itemtype = "http://schema.org/Article" >
< div itemprop = "articleBody" >
< div class = "section" id = "id1" >
< h1 > 表达式核心变量< a class = "headerlink" href = "#id1" title = "永久链接至标题" > ¶< / a > < / h1 >
< p > 无论是匹配表达式也好、观察表达式也罢，他们核心判断变量都是围绕着一个 Arthas 中的通用通知对象 < code class = "docutils literal notranslate" > < span class = "pre" > Advice< / span > < / code > 进行。< / p >
< p > 它的简略代码结构如下< / p >
< div class = "highlight-java notranslate" > < div class = "highlight hljs" > < pre class = "java" > public class Advice {
private final ClassLoader loader;
private final Class< ?> clazz;
private final ArthasMethod method;
private final Object target;
private final Object[] params;
private final Object returnObj;
private final Throwable throwExp;
private final boolean isBefore;
private final boolean isThrow;
private final boolean isReturn;
// getter/setter
} < / pre > < / div >
< / div >
< p > 这里列一个表格来说明不同变量的含义< / p >
< table border = "1" class = "docutils" >
< thead >
< tr >
< th align = "right" > 变量名< / th >
< th align = "left" > 变量解释< / th >
< / tr >
< / thead >
< tbody >
< tr >
< td align = "right" > loader< / td >
< td align = "left" > 本次调用类所在的 ClassLoader< / td >
< / tr >
< tr >
< td align = "right" > clazz< / td >
< td align = "left" > 本次调用类的 Class 引用< / td >
< / tr >
< tr >
< td align = "right" > method< / td >
< td align = "left" > 本次调用方法反射引用< / td >
< / tr >
< tr >
< td align = "right" > target< / td >
< td align = "left" > 本次调用类的实例< / td >
< / tr >
< tr >
< td align = "right" > params< / td >
< td align = "left" > 本次调用参数列表，这是一个数组，如果方法是无参方法则为空数组< / td >
< / tr >
< tr >
< td align = "right" > returnObj< / td >
< td align = "left" > 本次调用返回的对象。当且仅当 < code > isReturn==true< / code > 成立时候有效，表明方法调用是以正常返回的方式结束。如果当前方法无返回值 < code > void< / code > ，则值为 null< / td >
< / tr >
< tr >
< td align = "right" > throwExp< / td >
< td align = "left" > 本次调用抛出的异常。当且仅当 < code > isThrow==true< / code > 成立时有效，表明方法调用是以抛出异常的方式结束。< / td >
< / tr >
< tr >
< td align = "right" > isBefore< / td >
< td align = "left" > 辅助判断标记，当前的通知节点有可能是在方法一开始就通知，此时 < code > isBefore==true< / code > 成立，同时 < code > isThrow==false< / code > 和 < code > isReturn==false< / code > ，因为在方法刚开始时，还无法确定方法调用将会如何结束。< / td >
< / tr >
< tr >
< td align = "right" > isThrow< / td >
< td align = "left" > 辅助判断标记，当前的方法调用以抛异常的形式结束。< / td >
< / tr >
< tr >
< td align = "right" > isReturn< / td >
< td align = "left" > 辅助判断标记，当前的方法调用以正常返回的形式结束。< / td >
< / tr >
< / tbody >
< / table > < p > 所有变量都可以在表达式中直接使用，如果在表达式中编写了不符合 OGNL 脚本语法或者引入了不在表格中的变量，则退出命令的执行；用户可以根据当前的异常信息修正< code class = "docutils literal notranslate" > < span class = "pre" > 条件表达式< / span > < / code > 或< code class = "docutils literal notranslate" > < span class = "pre" > 观察表达式< / span > < / code > < / p >
< ul class = "simple" >
< li > < p > 特殊用法请参考：< a class = "reference external" href = "https://github.com/alibaba/arthas/issues/71" > https://github.com/alibaba/arthas/issues/71< / a > < / p > < / li >
< li > < p > OGNL表达式官网： < a class = "reference external" href = "https://commons.apache.org/proper/commons-ognl/language-guide.html" > https://commons.apache.org/proper/commons-ognl/language-guide.html< / a > < / p > < / li >
< / ul >
< / div >
< / div >
< / div >
< footer >
< hr / >
< div role = "contentinfo" >
< p >
© Copyright 2018-2020, Alibaba Middleware Group, and contributors
< / p >
< / div >
Built with < a href = "http://sphinx-doc.org/" > Sphinx< / a > using a < a href = "https://github.com/rtfd/sphinx_rtd_theme" > theme< / a > provided by < a href = "https://readthedocs.org" > Read the Docs< / a > .
< / footer >
< / div >
< / div >
< / section >
< / div >
< script type = "text/javascript" >
jQuery(function () {
SphinxRtdTheme.Navigation.enable(true);
});
< / script >
< div class = "github-fork-ribbon-wrapper right" >
< div class = "github-fork-ribbon" >
< a href = "https://github.com/alibaba/arthas" target = "_blank" > Fork me at GitHub< / a >
< / div >
< / div >
< script type = "text/javascript" src = "_static/add_badges.js" > < / script >
< script src = "https://cdnjs.cloudflare.com/ajax/libs/highlight.js/9.13.1/highlight.min.js" > < / script >
< script src = "https://cdnjs.cloudflare.com/ajax/libs/highlightjs-line-numbers.js/2.5.0/highlightjs-line-numbers.min.js" > < / script >
< script >
document.querySelectorAll('div.hljs > pre').forEach(function(block) {
hljs.highlightBlock(block);
hljs.lineNumbersBlock(block);
});
< / script >
< script >
var _hmt = _hmt || [];
(function() {
var hm = document.createElement("script");
if (window.location.hostname == "arthas.gitee.io") {
hm.src = "https://hm.baidu.com/hm.js?ecc1b0d9aeb73da1671876133211d4d3";
} else { // https://alibaba.github.io/arthas/
hm.src = "https://hm.baidu.com/hm.js?d5c5e25b100f0eb51a4c35c8a86ea9b4";
}
var s = document.getElementsByTagName("script")[0];
s.parentNode.insertBefore(hm, s);
})();
< / script >
< / body >
< / html >
