Mostrar el Estado de los Hilos en el Servidor.
A veces es necesario conocer el estado de los hilos en el servidor. Errores en código, memory leaks, bucles infinitos, etc. Normalmente uso VVM o JConsole para esta tarea pero a veces no es posible por restricciones de redes, configuración de la JVM etc. con lo que la mejor solución es subir un JSP al servidor.
Aquí dejo los ejemplos que uso:
Example 1
<%@ page language="java" contentType="text/html; charset=UTF-8"
pageEncoding="UTF-8"%>
<%@ page import="java.util.Set" %>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<title>Insert title here</title>
</head>
<body>
<%
Set<Thread> threadSet = Thread.getAllStackTraces().keySet();
Thread[] threadArray = threadSet.toArray(new Thread[threadSet.size()]);
int i = 0;
for(Thread threadaux :threadArray){
i++;
out.print(i+" "+threadaux.getName()+"<br/>");
}
%>
</body>
Example 2
<%@ page language="java" contentType="text/html; charset=UTF-8"
pageEncoding="UTF-8"%>
<%@ page import="java.io.PrintStream,
java.lang.management.ManagementFactory,
java.lang.management.ThreadInfo,
java.lang.management.ThreadMXBean"%>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<title>Quick and Dirty JSP Thread Report</title>
</head>
<body>
<%!
private static ThreadMXBean thMxBean =
ManagementFactory.getThreadMXBean();
private static String getTaskName(long id, String name) {
if (name == null) {
return Long.toString(id);
}
return id + " (" + name + ")<br>";
}
%><%
final int STACK_DEPTH = 20;
boolean contention = thMxBean.isThreadContentionMonitoringEnabled();
long[] threadIds = thMxBean.getAllThreadIds();
out.println("Process Thread Dump: <br/>");
out.println(threadIds.length + " active threads<br/>");
for (long tid : threadIds) {
ThreadInfo info = thMxBean.getThreadInfo(tid, STACK_DEPTH);
if (info == null) {
out.println(" Inactive");
continue;
}
out.println(" <br/><br/>Thread "
+ getTaskName(info.getThreadId(), info.getThreadName()));
Thread.State state = info.getThreadState();
out.println(" State: " + state);
out.println(" <br/>Blocked count: " + info.getBlockedCount());
out.println(" <br/>Waited count: " + info.getWaitedCount());
if (contention) {
out.println(" <br/>Blocked time: " + info.getBlockedTime());
out.println(" <br/> Waited time: " + info.getWaitedTime());
}
if (state == Thread.State.WAITING) {
out.println(" Waiting on " + info.getLockName());
} else if (state == Thread.State.BLOCKED) {
out.println(" Blocked on " + info.getLockName());
out.println(" Blocked by <br/>"
+ getTaskName(info.getLockOwnerId(),
info.getLockOwnerName()));
}
out.println(" <br/>Stack: ");
for (StackTraceElement frame : info.getStackTrace()) {
out.println(" " + frame.toString());
}
}%>
</body>
</html>
Example 3
<%@ page language="java" import="java.util.*,java.lang.Thread.*" contentType="text/html; charset=ISO-8859-1"
pageEncoding="ISO-8859-1"%>
<%--
Author:- Ramakanta(rks2286(at)gmail(dot)com)
Date Created: Mar 14 2010
PurPose: Online Java Thread Dump
Minimum Java version Required: 1.5.x
--%>
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=iso-8859-1">
<meta http-equiv="CACHE-CONTROL" content="NO-CACHE">
<title>Thread Dump</title>
</head>
<body>
<table width="100%" border="1" cellspacing="0" cellpadding="3" bordercolor="#000000">
<tr>
<td bgcolor="#E7E7EF" bordercolor="#000000" align="center" nowrap>
<font face="Verdana" size="+1">Thread Dumps </font>
</td>
</tr>
<tr>
<td bgcolor="#E7E7EF" bordercolor="#000000">
<%
out.print("---------------------------START-----------------------------------------<br>");
out.print("Generating Thread-Dump At:" + (new java.util.Date()).toString() + "<BR>");
out.println("---------------------------------------------------------------------<br>");
Map map = Thread.getAllStackTraces();
Iterator itr = map.keySet().iterator();
while (itr.hasNext()) {
Thread t = (Thread)itr.next();
StackTraceElement[] elem = (StackTraceElement[])map.get(t);
out.print("\"" + t.getName() + "\"");
out.print(" Priority=" + t.getPriority());
out.print(" Thread Id=" + t.getId());
State s = t.getState();
String state = null;
String color = "000000";
String GREEN = "00FF00";
String RED = "FF0000";
String ORANGE = "FCA742";
switch(s) {
case NEW: state ="NEW"; color = GREEN; break;
case BLOCKED: state = "BLOCKED"; color = RED; break;
case RUNNABLE: state = "RUNNABLE"; color = GREEN; break;
case TERMINATED: state = "TERMINATED"; break;
case TIMED_WAITING: state = "TIME WAITING"; color = ORANGE; break;
case WAITING: state = "WAITING"; color = RED; break;
}
out.print("<font color=\"" + color + "\"> In State :</font>");
out.println(" " + state + "<BR>");
for (int i=0; i < elem.length; i++) {
out.println(" at ");
out.print(elem[i].toString());
out.println("<BR>");
}
out.println("--------------------------------------------------------------------------<br>");
}
out.print("----------------------------FINISH--------------------------------------<br>");
out.print("Generated Thread-Dump At:" + (new java.util.Date()).toString() + "<BR>");
out.println("---------------------------------------------------------------------<br>");
%>
</td>
</tr>
</table>
</body>
</html>