java - JMX MBeanServer.queryMBeans 与查询 exp 不起作用

Question

我想使用 MBeanServer.queryMBeans(ObjectName name, QueryExp query) 来获取带有查询表达式的 MBean，但它似乎不适用于 QueryExp 查询。例如我有这样的测试代码:

public class CreateAndRegisterMBeanInMBeanServer {

/**
 * @param args
 */
public static void main(String[] args) throws Exception {

    String objectName = "com.javacodegeeks.snippets.enterprise:type=Hello";
    QueryExp exp = Query.eq(Query.attr("type"), Query.value("Hello"));


    MBeanServer server = ManagementFactory.getPlatformMBeanServer();

    // Construct the ObjectName for the Hello MBean we will register
    ObjectName mbeanName = new ObjectName(objectName);

    Hello mbean = new Hello();

    server.registerMBean(mbean, mbeanName);

    Set<ObjectInstance> instances = server.queryMBeans(new ObjectName(objectName), null);
    System.out.println(instances.size());

    for (int i = 0; i < instances.size(); i++) {
        ObjectInstance instance = (ObjectInstance) instances.toArray()[i];

        System.out.println("Class Name:t" + instance.getClassName());
        System.out.println("Object Name:t" + instance.getObjectName());
    }

}

static class Hello implements HelloMBean {

    private String message = "Hello World";

    @Override
    public String getMessage() {
        return this.message;
    }

    @Override
    public void sayHello() {
        System.out.println(message);
    }

    @Override
    public void setMessage(String message) {
        this.message = message;
    }

}

static interface HelloMBean {

    // operations

    public void sayHello();

    // attributes

    // a read-write attribute called Message of type String
    public String getMessage();

    public void setMessage(String message);

}

}

我可以得到预期的结果:1类名称:tCreateAndRegisterMBeanInMBeanServer$Hello对象名称:tcom.javacodegeeks.snippets.enterprise:type=Hello

但是如果我更改代码以使用定义的 QueryExp exp 为:

设置实例 = server.queryMBeans(new ObjectName(objectName), exp);

我看不到任何选定的 MBean，这是使用此类 Query Exp 的正确方法吗？

谢谢

Answer 1

改变

QueryExp exp = Query.eq(Query.attr("type"), Query.value("Hello"));

至

QueryExp exp = Query.eq(Query.attr("Message"), Query.value("Hello World"));

因为类型“type”不是一个属性。或者，如果您尝试按“类型”(ObjectName 的一部分)进行查询，则可以像这样构造对象名称:

String objectName = "*:type=Hello";

然后像以前一样进行查询:

Set<ObjectInstance> instances = server.queryMBeans(new ObjectName(objectName), null);