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轻松获取jvm线程的代码
<%@ page import="java.util.Iterator" %>
<%@ page import="java.util.Map" %>
<%@ page import="java.util.HashMap" %>
<%@ page contentType="text/html;charset=UTF-8" session="false" language="java"%>
<html>
<head>
<title>Threads</title>
<script>
function toggleStacks(id) {
var ele = document.getElementById(id);
if(!ele.style.display || ele.style.display != "none") {
ele.style.display = "none";
} else {
ele.style.display = "block";
}
return false;
}
</script>
<style type="text/css">
li {
list-style-type: none;
display: inline;
}
</style>
</head>
<body>
<a href="javascript:void(0)" onclick="return toggleStacks(‘system-res‘);">resource</a><br/>
<div id="system-res">
<ul>
<li>freeMemory: <%=Runtime.getRuntime().freeMemory()/(1024*1024)%>M;</li>
<li>totalMemory: <%=Runtime.getRuntime().totalMemory()/(1024*1024)%>M;</li>
<li>maxMemory: <%=Runtime.getRuntime().maxMemory()/(1024*1024)%>M;</li>
</ul>
</div>
<%
Map<Thread, StackTraceElement[]> allStacks = Thread.getAllStackTraces();
Map<Thread.State, Map<Thread, StackTraceElement[]>> classifyThreads = new HashMap<Thread.State, Map<Thread, StackTraceElement[]>>();
if (allStacks != null) {
Iterator<Map.Entry<Thread, StackTraceElement[]>> stackIterator = allStacks.entrySet().iterator();
while (stackIterator.hasNext()) {
Map.Entry<Thread, StackTraceElement[]> stackEntry = stackIterator.next();
Thread thread = stackEntry.getKey();
Thread.State state = thread.getState();
StackTraceElement[] traceElements = stackEntry.getValue();
Map<Thread, StackTraceElement[]> threadStacks = classifyThreads.get(state);
if(threadStacks == null) {
threadStacks = new HashMap<Thread, StackTraceElement[]>();
classifyThreads.put(state, threadStacks);
}
threadStacks.put(thread, traceElements);
}
}
for(Thread.State state : Thread.State.values()) {
Map<Thread, StackTraceElement[]> threadStacks = classifyThreads.get(state);
if(threadStacks != null) {
Iterator<Map.Entry<Thread, StackTraceElement[]>> stackIterator = threadStacks.entrySet().iterator();
out.println("<b>"+state.name()+"("+threadStacks.size()+")</b><br/><hr/>");
while (stackIterator.hasNext()) {
Map.Entry<Thread, StackTraceElement[]> stackEntry = stackIterator.next();
Thread thread = stackEntry.getKey();
StackTraceElement[] traceElements = stackEntry.getValue();
out.println("<pre>");
out.println("<a href=\"javascript:void(0);\" onclick=\"return toggleStacks(‘thread-"+thread.getId()+"‘);\">" + thread + "-" + thread.getState() + ":" + thread.getId() + "(" + traceElements.length + ")</a>");
if(traceElements != null) {
out.println("<div id=\"thread-"+thread.getId()+"\" style=\"display:none;\">");
for(StackTraceElement stack : traceElements) {
out.println(" " + stack + " - " + stack.getFileName());
}
out.println("<div>");
}
out.println("</pre>");
}
out.println("<br/>");
}
}
%>
</body>
</html>
实现类似jstack的功能
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原文地址：http://my.oschina.net/u/565351/blog/504803
