java 方法的重载

getPortIdentifier(CommPort port)
          Obtains the CommPortIdentifier object corresponding to a port that has already been opened by the application.

通过应用程序已经打开的串口获取 CommPortIdentifier  对象。

getPortIdentifier(java.lang.String portName)
          Obtains a CommPortIdentifier object by using a port name.

通过串口名获取 CommPortIdentifier 对象。

static java.util.Enumeration

getPortIdentifiers()
          Obtains an enumeration object that contains a CommPortIdentifier object for each port in the system.

获取一个枚举对象包含 系统中每一个串口的CommPortIdentifier 对象。

enumeration 接口中的对象是 CommPortIdentifier.