Posted on 2006-07-27 13:10
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JavaEE5/EJB3
Different from EJB services, which are provided by a pool of managed objects, a JMX MBean service is provided by a singleton object in the server JVM. This service object is stateful and has an application-wide scope.
JMX MBean服務以單例的形式存在于JVM中，它是有狀態并且存在于application范圍內。
1,定義JMX服務接口
public
?
interface
?Calculator?{
??
//
?Attribute
??
public
?
void
?setGrowthrate?(
double
?g);
??
public
?
double
?getGrowthrate?();
??
//
?The?management?method
??
public
?
double
?calculate?(
int
?start,?
int
?end,?
double
?saving);
??
//
?Life?cycle?method
??
public
?
void
?create?()?
throws
?Exception;
??
public
?
void
?destroy?()?
throws
?Exception;
}
你可以實現下面任意的JMX生命周期方法：
create() --
start() --
stop() --
destroy() --
2，定義JMX服務實現
@Service?(objectName
=
"
trail:service=calculator
"
)
@Management(Calculator.
class
)
public
?
class
?CalculatorMBean?
implements
?Calculator?{
??
double
?growthrate;
??
public
?
void
?setGrowthrate?(
double
?growthrate)?{
????
this
.growthrate?
=
?growthrate;
??}
??
public
?
double
?getGrowthrate?()?{
????
return
?growthrate;
??}
??
public
?
double
?calculate?(
int
?start,?
int
?end,?
double
?saving)?{
????
double
?tmp?
=
????????Math.pow(
1
.?
+
?growthrate?
/
?
12
.,?
12
.?
*
?(end?
-
?start)?
+
?
1
);
????
return
?saving?
*
?
12
.?
*
?(tmp?
-
?
1
)?
/
?growthrate;
??}
??
//
?Lifecycle?methods
??
public
?
void
?create()?
throws
?Exception?{
????growthrate?
=
?
0.08
;
????System.out.println(
"
Calculator?-?Creating
"
);
??}
??
public
?
void
?destroy()?{
????System.out.println(
"
Calculator?-?Destroying
"
);
??}
}
MBean的實現必須使用@Service標注，它用來告訴JBoss需要以objectName為命名將其注冊為一個MBean Service,@Management表示服務接口，可以有多個， 你可以在JMX控制臺(http://localhost:8080/jmx-console/) 通過trail:service=calculator找到這個服務
3，使用JMX MBean服務
calculator.jsp???
<%
@?page?
import
=
"
trail.jmx.*,?org.jboss.mx.util.*,
??????????????????java.text.
*
,?javax.management.
*
"
%>
?
<%!
??
private
?Calculator?cal?
=
?
null
;
??
public
?
void
?jspInit?()?{
????
try
?{
????????MBeanServer?server?
=
?MBeanServerLocator.locate();
????????cal?
=
?(Calculator)?MBeanProxyExt.create(
????????????Calculator.
class
,
????????????
"
trail:service=calculator
"
,
????????????server);
????}?
catch
?(Exception?e)?{
????????e.printStackTrace?();
????}
??}
%>
?
?
<%
???String?result;
???
int
?start?
=
?
25
;
???
int
?end?
=
?
65
;
???
double
?saving?
=
?
300.0
;
???
try
?{
?????start?
=
?Integer.parseInt(request.getParameter?(
"
start
"
));
?????end?
=
?Integer.parseInt(request.getParameter?(
"
end
"
));
?????saving?
=
?Double.parseDouble(request.getParameter?(
"
saving
"
));
?
?????NumberFormat?nf?
=
?NumberFormat.getInstance();
?????nf.setMaximumFractionDigits(
2
);
?????result?
=
?nf.format(cal.calculate(start,?end,?saving));
???}?
catch
?(Exception?e)?{
?????e.printStackTrace?();
?????result?
=
?
"
Not?valid
"
;
???}
?
%>
二、定義MBeans之間的依賴關系，
如同Ant中的任務一樣，用@Depends標注就可以了
@Service?(objectName
=
"
trail:service=investmentAdvisor
"
)
@Depends?({
"
trail:service=calculator
"
,
???????????
"
trail:service=riskAnalysis
"
})
public
?
class
?InvestmentAdvisorMBean?
implements
?InvestmentAdvisor?{
????
//
?
?
}
還有一種方法，使用依賴注入
@Service?(objectName
=
"
trail:service=investmentAdvisor
"
)
public
?
class
?InvestmentAdvisorMBean?
implements
?InvestmentAdvisor?{
????@Depends?(
"
trail:service=calculator
"
)
????
public
?
void
?setCalculator?(Calculator?calculator)?{
??????
this
.calculator?
=
?calculator;
????}
????
//
??
}
?