java串口编程-读取称重仪表中净重
一、需求说明
将仪表和计算机串口相连，计算机通过软件向仪表发送指令,然后仪表返回结果，在计算机软件界面上显示。
二、实现过程
1、查看仪表说明书
仪表型号为XK3190-A9，主要是查看相关参数（波特率、数据位、停止位、奇偶校验），通讯方式及指令规则。
2、使用串口通讯工具、串口监听工具进行调试
网上可以下到很多相关软件，主要是方便测试。串口通讯工具、串口监听工具（AccessPort）
3、将仪表“通讯方式”改成“指令模式”
根据说明书，在仪表上输入：打印设置--->98--->输入--->....
4、java编码(重点)
（1）使用comm在java程序中管理本地端口,目前，常见的Java串口包有SUN在1998年发布的串口通信API：comm2.0.jar（Windows下）、comm3.0.jar（Linux/Solaris）；IBM的串口通信API以及一个开源的实现。鉴于在Windows下SUN的API比较常用以及IBM的实现和SUN的在API层面都是一样的，那个开源的实现又不像两家大厂的产品那样让人放心，这里就只介绍SUN的串口通信API在Windows平台下的使用。
（2）附件中“javacomm20-win32.zip”
（3）解压该压缩包，从commapi\Readme.html开始读起
（4）Copy win32com.dll to your <JDK>\bin directory.
（5）Copy comm.jar、javax.comm.properties to your <APP>\lib directory.
（6）研究java.comm包中的相关类及功能
----javax.comm.CommPortIdentifier 这个类主要用于对串口进行管理和设置，是对串口进行访问控制的核心类。
----javax.comm.SerialPort 这个类用于描述一个RS-232串行通信端口的底层接口，它定义了串口通信所需的最小功能集。通过它，用户可以直接对串口进行读、写及设置工作。
（7）开始编写自己的代码
##### 串口参数配置(配置到spring容器里) #####
<?xml version="1.0" encoding="UTF-8"?> <!DOCTYPE beans PUBLIC "-//SPRING//DTD BEAN 2.0//EN" "http://www.springframework.org/dtd/spring-beans-2.0.dtd"> <beans> <bean class="self.phoenix.application.SerialParameters"> <!-- 端口名称 --> <property name="portName"><value>COM1</value></property> <!-- 波特率 --> <property name="baudRate"><value>4800</value></property> <!-- 输入流控制 --> <property name="flowControlIn"><value>0</value></property> <!-- 输出流控制 --> <property name="flowControlOut"><value>0</value></property> <!-- 数据位 --> <property name="databits"><value>8</value></property> <!-- 停止位 --> <property name="stopbits"><value>1</value></property> <!-- 奇偶校验 --> <property name="parity"><value>0</value></property> </bean> </beans>
#####用于处理注册驱动、打开端口、发送指令、关闭端口及释放资源#####
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import javax.comm.CommDriver;
import javax.comm.CommPortIdentifier;
import javax.comm.NoSuchPortException;
import javax.comm.PortInUseException;
import javax.comm.SerialPort;
import javax.comm.UnsupportedCommOperationException;
import self.phoenix.application.SerialConnectionException;
import self.phoenix.application.SerialParameters;
public class SerialConnUtils {
private OutputStream os= null;
private InputStream is = null;
private CommPortIdentifier portId = null;
private SerialPort sPort = null;
private SerialParameters parameters = null;
private CommDriver commDriver = null;
public SerialConnUtils(SerialParameters parameters) {
this.parameters = parameters;
if(commDriver == null){
try {
commDriver = (CommDriver) Class.forName("com.sun.comm.Win32Driver").newInstance();
commDriver.initialize();
} catch (InstantiationException e) {
e.printStackTrace();
} catch (IllegalAccessException e) {
e.printStackTrace();
} catch (ClassNotFoundException e) {
e.printStackTrace();
}
}
}
public void openConnection() throws SerialConnectionException {
// Obtain a CommPortIdentifier object for the port you want to open.
try {
portId = CommPortIdentifier.getPortIdentifier(parameters.getPortName());
} catch (NoSuchPortException e) {
throw new SerialConnectionException(e.getMessage());
}
// Open the port represented by the CommPortIdentifier object. Give
// the open call a relatively long timeout of 30 seconds to allow
// a different application to reliquish the port if the user
// wants to.
try {
sPort = (SerialPort)portId.open("SerialDemo", 30000);
} catch (PortInUseException e) {
throw new SerialConnectionException(e.getMessage());
}
try {
setConnectionParameters();
} catch (SerialConnectionException e) {
sPort.close();
throw e;
}
// Set receive timeout to allow breaking out of polling loop during
// input handling.
/*try {
sPort.enableReceiveTimeout(30);
} catch (UnsupportedCommOperationException e) {
}*/
}
public void setConnectionParameters() throws SerialConnectionException {
// Save state of parameters before trying a set.
int oldBaudRate = sPort.getBaudRate();
int oldDatabits = sPort.getDataBits();
int oldStopbits = sPort.getStopBits();
int oldParity = sPort.getParity();
int oldFlowControl = sPort.getFlowControlMode();
// Set connection parameters, if set fails return parameters object
// to original state.
try {
sPort.setSerialPortParams(parameters.getBaudRate(),
parameters.getDatabits(), parameters.getStopbits(),
parameters.getParity());
} catch (UnsupportedCommOperationException e) {
parameters.setBaudRate(oldBaudRate);
parameters.setDatabits(oldDatabits);
parameters.setStopbits(oldStopbits);
parameters.setParity(oldParity);
throw new SerialConnectionException("Unsupported parameter");
}
// Set flow control.
try {
sPort.setFlowControlMode(parameters.getFlowControlIn()
| parameters.getFlowControlOut());
} catch (UnsupportedCommOperationException e) {
throw new SerialConnectionException("Unsupported flow control");
}
}
/**
* 向端口发送十六进制指令 02 41 44 30 35 03
* 返回：02 41 44 2B 30 30 30 35 36 36 31 31 41 03
* @return 净重
* @throws SerialConnectionException
*/
public double sendSerialCommand() throws SerialConnectionException {
//十六进制指令
byte[] baKeyword = new byte[6];
baKeyword[0] = 0x02;
baKeyword[1] = 0x41;
baKeyword[2] = 0x44;
baKeyword[3] = 0x30;
baKeyword[4] = 0x35;
baKeyword[5] = 0x03;
//净重
Double netWeight = 0.0;
try {
//向串口发送指令
os = sPort.getOutputStream();
os.write(baKeyword, 0, baKeyword.length);
//用于从串口读数据,返回14字节的信息
byte[] readBuffer = new byte[14];
int numBytes = 0;
is = sPort.getInputStream();
numBytes = is.read(readBuffer);
System.out.println(new String(readBuffer));
//4~12为数据内容
String value = Hex2StringUtils.byte2HexStrByi(readBuffer,4,12);
if (value != null && !value.trim().equals(""))
netWeight = Double.valueOf(value) / 1000;
} catch (IOException e) {
e.printStackTrace();
}
return netWeight;
}
public void closeConnection() {
// Check to make sure sPort has reference to avoid a NPE.
if (sPort != null) {
try {
// close the i/o streams.
os.close();
is.close();
} catch (IOException e) {
System.err.println(e);
}
// Close the port.
sPort.close();
//Release resources
portId = null;
}
}
}
###### ACSII与16进制转换的Utils类 #####
import java.io.ByteArrayOutputStream;
import java.io.IOException;
public class Hex2StringUtils {
public static void main(String[] args) throws IOException {
}
/*
* 16进制数字字符集
*/
private static String hexString = "0123456789ABCDEF";
/*
* 将字符串编码成16进制数字,适用于所有字符（包括中文）
*/
public static String encode(String str) {
// 根据默认编码获取字节数组
byte[] bytes = str.getBytes();
StringBuilder sb = new StringBuilder(bytes.length * 2);
// 将字节数组中每个字节拆解成2位16进制整数
for (int i = 0; i < bytes.length; i++) {
sb.append(hexString.charAt((bytes[i] & 0xf0) >> 4));
sb.append(hexString.charAt((bytes[i] & 0x0f) >> 0));
}
return sb.toString();
}
/*
* 将16进制数字解码成字符串,适用于所有字符（包括中文）
*/
public static String decode(String bytes) {
ByteArrayOutputStream baos = new ByteArrayOutputStream(
bytes.length() / 2);
// 将每2位16进制整数组装成一个字节
for (int i = 0; i < bytes.length(); i += 2)
baos.write((hexString.indexOf(bytes.charAt(i)) << 4 | hexString
.indexOf(bytes.charAt(i + 1))));
return new String(baos.toByteArray());
}
public static String byte2HexStr(byte[] b) {
String hs = "";
String stmp = "";
for (int n = 0; n < b.length; n++) {
stmp = (Integer.toHexString(b[n] & 0XFF));
if (stmp.length() == 1)
hs = hs + "0" + stmp;
else
hs = hs + stmp;
// if (n<b.length-1) hs=hs+":";
}
return hs.toUpperCase();
}
public static String byteHexStr(byte b) {
String hs = "";
String stmp = "";
// /for (int n = 0; n < b.length; n++) {
stmp = (Integer.toHexString(b & 0XFF));
if (stmp.length() == 1)
hs = "0" + stmp;
else
hs = stmp;
// if (n<b.length-1) hs=hs+":";
// }
return hs.toUpperCase();
}
public static String byte2HexStrByi(byte[] b, int start, int end) {
String hs = "";
String stmp = "";
for (int n = start; n < end; n++) {
stmp = (Integer.toHexString(b[n] & 0XFF));
if (stmp.length() == 1)
hs = hs + decode("0" + stmp);
else
hs = hs + decode(stmp);
// if (n<b.length-1) hs=hs+":";
}
return hs.toUpperCase();
}
}
##### 调用函数，取得净重值 #####
public double getSerialPortNetWeight() {
double netWeight = 0;
SerialConnUtils serialConnUtils = null;
try {
//调用串口通讯工具类
serialConnUtils = new SerialConnUtils(parameters);
//打开连接
serialConnUtils.openConnection();
//发送指令，并取得返回值
netWeight = serialConnUtils.sendSerialCommand();
} catch (Exception ex) {
ex.printStackTrace();
} finally {
//释放资源
serialConnUtils.closeConnection();
}
return netWeight;
}
5、在串口监听工具配合下进行软件调试
129 [00000000] IRP_MJ_CREATE Port Opened - javaw.exe 130 [00000000] IOCTL_SERIAL_SET_BAUD_RATE Baud Rate: 4800 131 [00000000] IOCTL_SERIAL_SET_LINE_CONTROL StopBits: 1, Parity: No, DataBits: 8 132 [00000000] IOCTL_SERIAL_SET_BAUD_RATE Baud Rate: 9600 133 [00000000] IOCTL_SERIAL_SET_LINE_CONTROL StopBits: 1, Parity: No, DataBits: 8 134 [00000000] IOCTL_SERIAL_SET_BAUD_RATE Baud Rate: 9600 135 [00000000] IOCTL_SERIAL_SET_LINE_CONTROL StopBits: 1, Parity: No, DataBits: 8 136 [00000000] IOCTL_SERIAL_SET_BAUD_RATE Baud Rate: 4800 137 [00000000] IOCTL_SERIAL_SET_LINE_CONTROL StopBits: 1, Parity: No, DataBits: 8 138 [00000000] IOCTL_SERIAL_SET_BAUD_RATE Baud Rate: 4800 139 [00000000] IOCTL_SERIAL_SET_LINE_CONTROL StopBits: 1, Parity: No, DataBits: 8 140 [00000000] IOCTL_SERIAL_SET_BAUD_RATE Baud Rate: 4800 141 [00000000] IOCTL_SERIAL_SET_LINE_CONTROL StopBits: 1, Parity: No, DataBits: 8 142 [00000000] IRP_MJ_WRITE Length: 0006, Data: 02 41 44 30 35 03 143 [00000013] IRP_MJ_READ Length: 0014, Data: 02 41 44 2B 30 30 30 35 36 36 31 31 41 03 144 [00001356] IRP_MJ_CLOSE Port Closed 145 [00000000] IRP_MJ_CREATE Port Opened - javaw.exe 146 [00000000] IOCTL_SERIAL_SET_BAUD_RATE Baud Rate: 4800 147 [00000000] IOCTL_SERIAL_SET_LINE_CONTROL StopBits: 1, Parity: No, DataBits: 8 148 [00000000] IOCTL_SERIAL_SET_BAUD_RATE Baud Rate: 9600 149 [00000000] IOCTL_SERIAL_SET_LINE_CONTROL StopBits: 1, Parity: No, DataBits: 8 150 [00000000] IOCTL_SERIAL_SET_BAUD_RATE Baud Rate: 9600 151 [00000000] IOCTL_SERIAL_SET_LINE_CONTROL StopBits: 1, Parity: No, DataBits: 8 152 [00000000] IOCTL_SERIAL_SET_BAUD_RATE Baud Rate: 4800 153 [00000000] IOCTL_SERIAL_SET_LINE_CONTROL StopBits: 1, Parity: No, DataBits: 8 154 [00000000] IOCTL_SERIAL_SET_BAUD_RATE Baud Rate: 4800 155 [00000000] IOCTL_SERIAL_SET_LINE_CONTROL StopBits: 1, Parity: No, DataBits: 8 156 [00000000] IOCTL_SERIAL_SET_BAUD_RATE Baud Rate: 4800 157 [00000000] IOCTL_SERIAL_SET_LINE_CONTROL StopBits: 1, Parity: No, DataBits: 8 158 [00000000] IRP_MJ_WRITE Length: 0006, Data: 02 41 44 30 35 03 159 [00000013] IRP_MJ_READ Length: 0014, Data: 02 41 44 2B 30 30 30 36 39 36 31 31 36 03 160 [00000349] IRP_MJ_CLOSE Port Closed
Length:0006, Data:02 41 44 30 35 03 为发送的十六进制指令
Length:0014, Data:02 41 44 2B 30 30 30 36 39 36 31 31 36 03 为返回的十六进制内容
三、总结：调试过程中，串口监听工具起着很重要的作用。