Java serial programming (1)

I. Environment configuration (1) decompress and copy the file

Decompress javacomm20-win32.zip

Copy win32com. DLL to the <java_home>/JRE/bin and <JDK>/bin directories.

Copy comm. jar to the <java_home>/JRE/lib/EXT and <JDK>/lib directories.

Copy javax. Comm. properties to the <java_home>/JRE/lib and <JDK>/lib directories.

(2) Set Environment Variables

Classpath = <java_home>/JRE/lib/EXT/COMM. jar; % classpath %

(3) Add the jar package to the Eclipse project

Right-click the project and choose Properties> JAVA build path> libraries> Add external jar to find the location of Comm. jar in <JDK>/lib.

Ii. API overview Interface

Part of the loadable Device Driver Interface

Commp ortownershiplistener transmits ownership events of various communication ports

Parallelporteventlistener transmits parallel port events

Serialporteventlistener transmits a serial port event

Class

Comport Communication Port

Commp ortidentifier Communication Port Management

Parallelport: Parallel Communication Port

Parallelportevent parallel port event

SerialPort RS-232 serial communication port

Serialportevent exception class

Nosuchportexception thrown when the driver cannot find the specified port

Portinuseexception thrown when a specified port is in use

The unsupportedcommoperationexception driver cannot throw

(1) commp ORT class

Abstract class that describes the ports supported by the underlying system. It includes some high-level Io control methods, which are common for all different communication ports. Both SerialPort and parallelport are its subclasses.

(2) commp ortidentifier

It is mainly used to manage and set serial ports and is the core class for access control over serial ports. The main method is as follows:

Addportname (string, Int, commdriver): add the port name to the port list.

Addportownershiplistener (commp ortownershiplistener) add listener owned by the port

Removeportownershiplistener (commp ortownershiplistener) removes listener owned by the port

Getcurrentowner () obtains the object or application that currently occupies the port.

Get the port name by getname ()

Getportidentifier (comport) obtains the comportidentifier type object of the port opened by the parameter.

Getportidentifier (string) is used to obtain the commp ortidentifier type object of the port named after the parameter.

Getportidentifiers () to obtain the list of ports in the system

Getporttype () indicates the port type.

Iscurrentlyowned () checks whether the current port is occupied

Open (filedescriptor) open the port with the type described in the file

Open (string, INT) Open Port, two parameters: program name, delay time (milliseconds)

(3) SerialPort

Describes the underlying interface of the RS-232 serial communication port, which defines the minimum function set required for serial communication. You can directly read, write, and set the serial port.

A: serial port parameter functions

Getbaudrate () Get the baud rate getparity () Get the test Type

Getdatabits () Get the data bits getstopbits () Get the Stop bits

Setserialportparams (INT, Int, Int, INT) sets the serial port parameters to (baud rate, data bit, stop bit, parity check) in sequence)

Close () Close the serial port

Getoutputstream () gets the output stream of the outputstream type.

Getinputstream () obtains the inputstream input stream.

B: Events and event Methods

Whether iscd () has a carrier

Iscts () Whether to clear sending

Isdsr () Data ready

Isdtr () Data Terminal ready

ISRI (): whether to enable Alarm Detection

Whether isrts () requires sending

Addeventlistener (serialporteventlistener) adds a serial event listener to the SerialPort object

Removeeventlistener () removes the serial event listener from the SerialPort object.

Geteventtype () returns the int type as the event type.

Sendbreak (INT) specifies the duration of the interrupt process. The parameter value is millisecond.

Setrts (Boolean) sets or clears the RTS bit

Setdtr (Boolean) set or clear DTR bit

Notifyonbreakinterrupt (Boolean) sets the interrupt event

Notifyoncarrierdetect (Boolean) sets the carrier listening event

Notifyoncts (Boolean) sets to clear sending events

Notifyondataavailable (Boolean) sets an event with data in the serial port

Notifyondsr (Boolean) sets data backup events

Notifyonframingerror (Boolean) is used to set an error event.

Notifyonoutputempty (Boolean) sets the sending buffer to a null event

Notifyonparityerror (Boolean) is used to set a parity check error event.

Notifyonringindicator (Boolean)

C: static member variables of serial port Parameters

Description of member variables description of member variables

Databits_5 data bit: 5 stopbits_2 stop bit: 2 parity_odd odd Test

Databits_6 data bit: 6 stopbits_1 stop bit: 1 parity_mark mark Test

Databits_7 data bit is 7 stopbits_00005 stop is 1.5 parity_none Space Test

Databits_8 data bit: 8 parity_even even test parity_space no test