最近,我们的web服务老是自动的就死掉了,为此,头儿让我们几个轮流值班,时刻注视web服务,如果web服务死掉了,我们需要立刻启动它.
这个方法,又劳民又伤才.谁都不愿意值班,怎么办?
我想了一下,写个监控web服务的程序不就得了?
可以有多种监控方式:
1:传统桌面程序.
2:b/s的监控程序.
先试验一个传统桌面程序.
先做个试验:监控foxmail.exe是否运行,如果没有运行,就启动它.
在系统的进程列表中,foxmail.exe中的进程名称为foxmail.exe,如果有名称为foxmail.exe的进程,这进行任何动作,否则启动它.
//---------------------------------------------------------------------------
#include <vcl.h>
#pragma hdrstop
#include "Tlhelp32.h"
#include "Unit1.h"
//---------------------------------------------------------------------------
#pragma package(smart_init)
#pragma resource "*.dfm"
TForm1 *Form1;
//---------------------------------------------------------------------------
__fastcall TForm1::TForm1(TComponent* Owner)
: TForm(Owner)
{
}
//---------------------------------------------------------------------------
void __fastcall TForm1::Button1Click(TObject *Sender)
{
Timer1->Enabled = true;
}
//---------------------------------------------------------------------------
void __fastcall TForm1::Timer1Timer(TObject *Sender)
{
try{
HANDLE SnapShot=CreateToolhelp32Snapshot(TH32CS_SNAPPROCESS,0);
if (SnapShot == INVALID_HANDLE_VALUE)
return;
PROCESSENTRY32 ProcessInfo;
ProcessInfo.dwSize=sizeof(ProcessInfo);
BOOL Status=Process32First(SnapShot,&ProcessInfo);
BOOL flag = false; //是否有foxmail.exe进程
while(Status)
{
if(AnsiString(ProcessInfo.szExeFile).LowerCase() == "foxmail.exe")
{
flag = true;
}
Status=Process32Next(SnapShot,&ProcessInfo);
}
AnsiString tempTime = FormatDateTime("yyyy,mm,dd,hh:nn:ss", Now());
if(!flag){
AnsiString Exename = "D:\\Program Files\\Foxmail\\Foxmail.exe";
ShellExecute(Handle,"open",Exename.c_str(),"","", SW_SHOW );
Memo1->Lines->Add("restart this program at " + tempTime);
}
else{
Memo1->Lines->Add("running at " + tempTime);
}
CloseHandle (SnapShot);
}catch(...){
}
}
//---------------------------------------------------------------------------
void __fastcall TForm1::Button2Click(TObject *Sender)
{
Timer1->Enabled = false;
}
//---------------------------------------------------------------------------
这个程序可以成功监控foxmail.exe的运行,如果foxmail.exe停掉了,则自动启动它.
可是:我们的web服务程序在进程中为:java.exe,并且有两个.怎么办?
有一个近似的方法:如果进程中有两个java.exe,则认为web服务良好,如果java.exe少于两个,则认为web停了,需要重新启动.
所以修改后得到如下程序:
void __fastcall TForm1::Button1Click(TObject *Sender)
{
i = StrToInt(Edit1->Text); //i为全局变量,记录应该有的java数目,这里为2.
Timer1->Enabled = true;
}
//---------------------------------------------------------------------------
void __fastcall TForm1::Timer1Timer(TObject *Sender)
{
try{
HANDLE SnapShot=CreateToolhelp32Snapshot(TH32CS_SNAPPROCESS,0);
if (SnapShot == INVALID_HANDLE_VALUE)
return;
PROCESSENTRY32 ProcessInfo;
ProcessInfo.dwSize=sizeof(ProcessInfo);
BOOL Status=Process32First(SnapShot,&ProcessInfo);
int j = 0; //记录当前java.exe数目
while(Status)
{
if(AnsiString(ProcessInfo.szExeFile).LowerCase() == "java.exe")
{
j++;
}
Status=Process32Next(SnapShot,&ProcessInfo);
}
AnsiString tempTime = FormatDateTime("yyyy,mm,dd,hh:nn:ss", Now());
if(j<i){
AnsiString Exename = "C:\\bea\\user_projects\\domains\\HBEP\\autoStart.cmd";
ShellExecute(Handle,"open",Exename.c_str(),"","", SW_SHOW );
Memo1->Lines->Add("restart this program at " + tempTime);
}
else{
Memo1->Lines->Add("running at " + tempTime);
}
CloseHandle (SnapShot);
}catch(...){
}
}
似乎并不满意,因为任何一个java程序的运行,在系统的进程表中都叫java.exe.怎么办?(虽然我们的服务器上很干净,基本不运行其他的java程序).
采用另外的一个方法:xmlhttp技术:
我的想法是这样的:
我们的web服务器是weblogic,我在服务器上另外部署一个tomcat服务器,分别在两个web服务里面写一个servlet,
然后写一个html文件(不需要步署),采用xmlhttp技术访问weblogic的servlet(假定为A),如果A有响应,则表明weblogic服务在运行,如果连续5次无响应,则
认为weblogic服务死掉了,此时给tomcat的servlet(假定为B)发送一个xml命令,让servlet执行启动weblogic服务的操作:
Runtime.getRuntime().exec( "cmd /c start C:\\bea\\user_projects\\domains\\HBEP\\autoStart.cmd");
html文件如下(采用xmlhttp给servlet发送xml命令):
<BODY>
<script language="javascript">
var XML="<root><test>ask</test></root>" //定义一个ask命令,发送给servlet
var XMLrestart="<root><test>restart</test></root>"
var xmlHttp = new ActiveXObject("Msxml2.XMLHTTP");
var xmlDoc=new ActiveXObject("Msxml2.DOMDocument");
function readxml(myXML){//客户端xml的解析
xmlDoc.loadXML(myXML);
if(xmlDoc.parseError.line>0){
throw xmlDoc.parseError.reason;
}
var nodes= xmlDoc.selectNodes("/root/test");
for(var i=0;i<nodes.length;i++){
return(nodes.item(i).text);
}
}
function action(){//客户端和服务端的通讯
xmlHttp.open("post","http://127.0.0.1:7001/xmlhttpTest/UrlTestServlet",false);
xmlHttp.setRequestHeader("context-type","text/xml;charset=utf-8");
xmlHttp.send(XML);
var answerxml = xmlHttp.responseText;
if(readxml(answerxml))!='ok'{ //没有接到servlet的响应,认为weblogic关闭,则向tomcat的servlet发送"restart"命令
xmlHttp.open("post","http://127.0.0.1:8888/xmlhttpTest/UrlTestServlet",false);
xmlHttp.setRequestHeader("context-type","text/xml;charset=utf-8");
xmlHttp.send(XMLrestart);
var answerxmlFromWeblogic = xmlHttp.responseText;
}
}
</script>
<button onclick="action();">朝服务器传送xml，并接收服务器回应</button>
</BODY>
再在weblogic部署一个servlet,内容如下:
package com.lcl;
import javax.servlet.*;
import javax.servlet.http.*;
import java.io.*;
import java.util.*;
import org.dom4j.io.*;
import org.dom4j.*;
/**
* @author lcl
*
* TODO 要更改此生成的类型注释的模板，请转至
* 窗口 － 首选项 － Java － 代码样式 － 代码模板
*/
public class UrlTestServlet extends HttpServlet {
private static final String CONTENT_TYPE = "text/xml;charset=utf-8";
//Initialize global variables
public void init() throws ServletException {
}
//Process the HTTP Get request
public void doGet(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
response.setContentType(CONTENT_TYPE);
request.setCharacterEncoding("utf-8");
PrintWriter out = response.getWriter();
InputStream is=request.getInputStream();
SAXReader reader=new SAXReader();
Document doc=null;
try{
doc=reader.read(is);
} catch(Exception ex){
System.out.println(ex);
}
String[] s= getElementTexts(doc,"test");
out.println("<root>");
out.println("<test>");
out.println("ok");
out.println("</test></root>");
}
public void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
doGet(request,response);
}
private String getElementText(Document doc,String name){
return doc.getRootElement().element(name).getText();
}
private String[] getElementTexts(Document doc,String name){
List l=doc.getRootElement().elements(name);
Iterator it=l.iterator();
List l1=new LinkedList();
while(it.hasNext()){
Element e=(Element)it.next();
l1.add(e.getText());
}
return (String[])l1.toArray(new String[]{});
}
//Clean up resources
public void destroy() {
}
}
weblogic的web.xml更改如下(加servlet映射):
<?xml version="1.0" encoding="ISO-8859-1"?>
<!DOCTYPE web-app
PUBLIC "-//Sun Microsystems, Inc.//DTD Web Application 2.3//EN"
"http://java.sun.com/dtd/web-app_2_3.dtd">
<web-app>
<display-name>Welcome to Tomcat</display-name>
<description>
Welcome to Tomcat
</description>
<!-- JSPC servlet mappings start -->
<servlet>
<servlet-name>UrlTestServlet</servlet-name>
<servlet-class>com.lcl.UrlTestServlet</servlet-class>
</servlet>
<servlet-mapping>
<servlet-name>UrlTestServlet</servlet-name>
<url-pattern>/UrlTestServlet</url-pattern>
</servlet-mapping>
<!-- JSPC servlet mappings end -->
<welcome-file-list>
<welcome-file>index.htm</welcome-file>
</welcome-file-list>
</web-app>
tomcat的servlet和weblogic的servlet类似,只是在收到restart命令后执行:
Runtime.getRuntime().exec( "cmd /c start C:\\bea\\user_projects\\domains\\HBEP\\autoStart.cmd");
ok,搞定了,现在可以高枕无忧了.
甚至可以做到weblogic和tomcat的互启动.
现在不用值班了.呵呵
特此存档.
