java开发usb实例

java开发usb实例 1Preface 1.1Introduction JSR80istheJavaSpecificationRequestconcernedwithcommunicationwithUniversalSerialBus(USB) devices.ThisdocumentdescribestheAPIassociatedwiththisJSR. 2USBBusTopology ThestructureoftheUSBbusistopological.TherootoftheUSBphysicalbusisaphysicalHostCon- troller,whichiscontainedinacomputersystem.HostControllersareusuallyon-boardormaybeadd-in PCIcards.Theyappearlogicallyashubs,sotheyaretheroothubintheirowntopologytree.Connected tothemareoneormoreUSBdevices,andsinceUSBhubsareatypeofUSBdevice,thistopology may continuedownuntiltherearenomoreconnecteddevices.Thenon-hubdevicesformtheleavesofthe topologytree,whilethehub