使用java的modbus4j的Rtu方式獲取監測數據

最近要從modbus總線上獲取數據，還要用java開發，找了半天，感覺modbus4j在github上評價比較高，嘗試了一下，果然很好用，比之前的方法方便很多。在使用過程中也踩了不少坑，記錄下來，分享給大家，100%好用，上傳了全部代碼，東西一點都不缺少。

1、配置串口環境
使用virtual serial port driver模擬串口com1、com2

2、配置下位機環境
使用modsim模擬下位設備
deviceid：設備ID
modbus point type：寄存器模式
address：寄存器起始位置
length：寄存器存儲長度

選擇COM1口

3、上位機接口使用java的modbus4j實現
modbus4j的SerialPortWrapper接口沒有實現類，推薦使用Freedomotic中的三個類實現：
SerialPortWrapperImpl.java
SerialInputStream.java
SerialOutputStream.java

爲了大家使用方便，這裏直接上源代碼
SerialPortWrapperImpl.java

package com.dj.collection;

/**
 *
 * Copyright (c) 2009-2020 Freedomotic Team http://www.freedomotic-iot.com
 *
 * This file is part of Freedomotic
 *
 * This Program is free software; you can redistribute it and/or modify it under
 * the terms of the GNU General Public License as published by the Free Software
 * Foundation; either version 2, or (at your option) any later version.
 *
 * This Program is distributed in the hope that it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
 * FOR A PARTICULAR PURPOSE. See the GNU General Public License for more
 * details.
 *
 * You should have received a copy of the GNU General Public License along with
 * Freedomotic; see the file COPYING. If not, see
 * <http://www.gnu.org/licenses/>.
 */

import com.serotonin.modbus4j.serial.SerialPortWrapper;
import jssc.SerialPort;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import java.io.InputStream;
import java.io.OutputStream;
import java.util.ArrayList;
import java.util.List;
import jssc.SerialPortException;

/**
 *
 */
public class SerialPortWrapperImpl implements SerialPortWrapper {

    private static final Logger LOG = LoggerFactory.getLogger(SerialPortWrapperImpl.class);
    private SerialPort port;
    private String commPortId;
    private int baudRate;
    private int dataBits;
    private int stopBits;
    private int parity;
    private int flowControlIn;
    private int flowControlOut;

    public SerialPortWrapperImpl(String commPortId, int baudRate, int dataBits, int stopBits, int parity, int flowControlIn,
                                 int flowControlOut) {

        this.commPortId = commPortId;
        this.baudRate = baudRate;
        this.dataBits = dataBits;
        this.stopBits = stopBits;
        this.parity = parity;
        this.flowControlIn = flowControlIn;
        this.flowControlOut = flowControlOut;

        port = new SerialPort(this.commPortId);

    }

    @Override
    public void close() throws Exception {
        port.closePort();
        //listeners.forEach(PortConnectionListener::closed);
        LOG.debug("Serial port {} closed", port.getPortName());
    }

    @Override
    public void open() {
        try {
            port.openPort();
            port.setParams(this.getBaudRate(), this.getDataBits(), this.getStopBits(), this.getParity());
            port.setFlowControlMode(this.getFlowControlIn() | this.getFlowControlOut());

            //listeners.forEach(PortConnectionListener::opened);
            LOG.debug("Serial port {} opened", port.getPortName());
        } catch (SerialPortException ex) {
            LOG.error("Error opening port : {} for {} ", port.getPortName(), ex);
        }
    }

    @Override
    public InputStream getInputStream() {
        return new SerialInputStream(port);
    }

    @Override
    public OutputStream getOutputStream() {
        return new SerialOutputStream(port);
    }

    @Override
    public int getBaudRate() {
        return baudRate;
        //return SerialPort.BAUDRATE_9600;
    }

    @Override
    public int getFlowControlIn() {
        return flowControlIn;
        //return SerialPort.FLOWCONTROL_NONE;
    }

    @Override
    public int getFlowControlOut() {
        return flowControlOut;
        //return SerialPort.FLOWCONTROL_NONE;
    }

    @Override
    public int getDataBits() {
        return dataBits;
        //return SerialPort.DATABITS_8;
    }

    @Override
    public int getStopBits() {
        return stopBits;
        //return SerialPort.STOPBITS_1;
    }

    @Override
    public int getParity() {
        return parity;
        //return SerialPort.PARITY_NONE;
    }
}

SerialInputStream.java
126行、127行必須進行如下修改

//            System.arraycopy(readBuf, 0, buf, offset, length);
            System.arraycopy(readBuf, 0, buf, offset, readBuf.length);

package com.dj.collection;

/*
 * To change this template, choose Tools | Templates
 * and open the template in the editor.
 */

import jssc.SerialPort;

import java.io.IOException;
import java.io.InputStream;

/**
 * Class that wraps a {@link SerialPort} to provide {@link InputStream}
 * functionality. This stream also provides support for performing blocking
 * reads with timeouts.
 * <br>
 * It is instantiated by passing the constructor a {@link SerialPort} instance.
 * Do not create multiple streams for the same serial port unless you implement
 * your own synchronization.
 *
 * @author Charles Hache <[email protected]>
 *
 * Attribution: https://github.com/therealchalz/java-simple-serial-connector
 *
 */
public class SerialInputStream extends InputStream {

    private SerialPort serialPort;
    private int defaultTimeout = 0;

    /**
     * Instantiates a SerialInputStream for the given {@link SerialPort} Do not
     * create multiple streams for the same serial port unless you implement
     * your own synchronization.
     *
     * @param sp The serial port to stream.
     */
    public SerialInputStream(SerialPort sp) {
        serialPort = sp;
    }

    /**
     * Set the default timeout (ms) of this SerialInputStream. This affects
     * subsequent calls to {@link #read()}, {@link #blockingRead(int[])}, and
     * {@link #blockingRead(int[], int, int)} The default timeout can be 'unset'
     * by setting it to 0.
     *
     * @param time The timeout in milliseconds.
     */
    public void setTimeout(int time) {
        defaultTimeout = time;
    }

    /**
     * Reads the next byte from the port. If the timeout of this stream has been
     * set, then this method blocks until data is available or until the timeout
     * has been hit. If the timeout is not set or has been set to 0, then this
     * method blocks indefinitely.
     */
    @Override
    public int read() throws IOException {
        return read(defaultTimeout);
    }

    /**
     * The same contract as {@link #read()}, except overrides this stream's
     * default timeout with the given timeout in milliseconds.
     *
     * @param timeout The timeout in milliseconds.
     * @return The read byte.
     * @throws IOException On serial port error or timeout
     */
    public int read(int timeout) throws IOException {
        byte[] buf = new byte[1];
        try {
            if (timeout > 0) {
                buf = serialPort.readBytes(1, timeout);
            } else {
                buf = serialPort.readBytes(1);
            }
            return buf[0];
        } catch (Exception e) {
            throw new IOException(e);
        }
    }

    /**
     * Non-blocking read of up to buf.length bytes from the stream. This call
     * behaves as read(buf, 0, buf.length) would.
     *
     * @param buf The buffer to fill.
     * @return The number of bytes read, which can be 0.
     * @throws IOException on error.
     */
    @Override
    public int read(byte[] buf) throws IOException {
        return read(buf, 0, buf.length);
    }

    /**
     * Non-blocking read of up to length bytes from the stream. This method
     * returns what is immediately available in the input buffer.
     *
     * @param buf The buffer to fill.
     * @param offset The offset into the buffer to start copying data.
     * @param length The maximum number of bytes to read.
     * @return The actual number of bytes read, which can be 0.
     * @throws IOException on error.
     */
    @Override
    public int read(byte[] buf, int offset, int length) throws IOException {

        if (buf.length < offset + length) {
            length = buf.length - offset;
        }

        int available = this.available();

        if (available > length) {
            available = length;
        }

        try {
            byte[] readBuf = serialPort.readBytes(available);
//            System.arraycopy(readBuf, 0, buf, offset, length);
            System.arraycopy(readBuf, 0, buf, offset, readBuf.length);
            return readBuf.length;
        } catch (Exception e) {
            throw new IOException(e);
        }
    }

    /**
     * Blocks until buf.length bytes are read, an error occurs, or the default
     * timeout is hit (if specified). This behaves as blockingRead(buf, 0,
     * buf.length) would.
     *
     * @param buf The buffer to fill with data.
     * @return The number of bytes read.
     * @throws IOException On error or timeout.
     */
    public int blockingRead(byte[] buf) throws IOException {
        return blockingRead(buf, 0, buf.length, defaultTimeout);
    }

    /**
     * The same contract as {@link #blockingRead(byte[])} except overrides this
     * stream's default timeout with the given one.
     *
     * @param buf The buffer to fill.
     * @param timeout The timeout in milliseconds.
     * @return The number of bytes read.
     * @throws IOException On error or timeout.
     */
    public int blockingRead(byte[] buf, int timeout) throws IOException {
        return blockingRead(buf, 0, buf.length, timeout);
    }

    /**
     * Blocks until length bytes are read, an error occurs, or the default
     * timeout is hit (if specified). Saves the data into the given buffer at
     * the specified offset. If the stream's timeout is not set, behaves as
     * {@link #read(byte[], int, int)} would.
     *
     * @param buf The buffer to fill.
     * @param offset The offset in buffer to save the data.
     * @param length The number of bytes to read.
     * @return the number of bytes read.
     * @throws IOException on error or timeout.
     */
    public int blockingRead(byte[] buf, int offset, int length) throws IOException {
        return blockingRead(buf, offset, length, defaultTimeout);
    }

    /**
     * The same contract as {@link #blockingRead(byte[], int, int)} except
     * overrides this stream's default timeout with the given one.
     *
     * @param buf The buffer to fill.
     * @param offset Offset in the buffer to start saving data.
     * @param length The number of bytes to read.
     * @param timeout The timeout in milliseconds.
     * @return The number of bytes read.
     * @throws IOException On error or timeout.
     */
    public int blockingRead(byte[] buf, int offset, int length, int timeout) throws IOException {
        if (buf.length < offset + length) {
            throw new IOException("Not enough buffer space for serial data");
        }

        if (timeout < 1) {
            return read(buf, offset, length);
        }

        try {
            byte[] readBuf = serialPort.readBytes(length, timeout);
            System.arraycopy(readBuf, 0, buf, offset, length);
            return readBuf.length;
        } catch (Exception e) {
            throw new IOException(e);
        }
    }

    @Override
    public int available() throws IOException {
        int ret;
        try {
            ret = serialPort.getInputBufferBytesCount();
            if (ret >= 0) {
                return ret;
            }
            throw new IOException("Error checking available bytes from the serial port.");
        } catch (Exception e) {
            throw new IOException("Error checking available bytes from the serial port.");
        }
    }

}

SerialOutputStream.java

package com.dj.collection;

/**
 *
 * Copyright (c) 2009-2020 Freedomotic Team http://www.freedomotic-iot.com
 *
 * This file is part of Freedomotic
 *
 * This Program is free software; you can redistribute it and/or modify it under
 * the terms of the GNU General Public License as published by the Free Software
 * Foundation; either version 2, or (at your option) any later version.
 *
 * This Program is distributed in the hope that it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
 * FOR A PARTICULAR PURPOSE. See the GNU General Public License for more
 * details.
 *
 * You should have received a copy of the GNU General Public License along with
 * Freedomotic; see the file COPYING. If not, see
 * <http://www.gnu.org/licenses/>.
 */

import jssc.SerialPort;
import jssc.SerialPortException;

import java.io.IOException;
import java.io.OutputStream;

/**
 * Class that wraps a {@link SerialPort} to provide {@link OutputStream}
 * functionality.
 * <br>
 * It is instantiated by passing the constructor a {@link SerialPort} instance.
 * Do not create multiple streams for the same serial port unless you implement
 * your own synchronization.
 *
 * @author Charles Hache <[email protected]>
 *
 * Attribution: https://github.com/therealchalz/java-simple-serial-connector
 *
 */
public class SerialOutputStream extends OutputStream {

    SerialPort serialPort;

    /**
     * Instantiates a SerialOutputStream for the given {@link SerialPort} Do not
     * create multiple streams for the same serial port unless you implement
     * your own synchronization.
     *
     * @param sp The serial port to stream.
     */
    public SerialOutputStream(SerialPort sp) {
        serialPort = sp;
    }

    @Override
    public void write(int b) throws IOException {
        try {
            serialPort.writeInt(b);
        } catch (SerialPortException e) {
            throw new IOException(e);
        }
    }

    @Override
    public void write(byte[] b) throws IOException {
        write(b, 0, b.length);

    }

    @Override
    public void write(byte[] b, int off, int len) throws IOException {
        byte[] buffer = new byte[len];
        System.arraycopy(b, off, buffer, 0, len);
        try {
            serialPort.writeBytes(buffer);
        } catch (SerialPortException e) {
            throw new IOException(e);
        }
    }
}

4、pom.xml文件

<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0"
         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>

    <groupId>org.example</groupId>
    <artifactId>data-collection</artifactId>
    <version>1.0-SNAPSHOT</version>
    <build>
        <plugins>
            <plugin>
                <groupId>org.apache.maven.plugins</groupId>
                <artifactId>maven-compiler-plugin</artifactId>
                <configuration>
                    <source>6</source>
                    <target>6</target>
                </configuration>
            </plugin>
        </plugins>
    </build>

    <!-- 若想引用modbus4j需要引入下列repository id:ias-snapshots id:ias-releases 兩個 -->
    <repositories>
        <repository>
            <releases>
                <enabled>false</enabled>
            </releases>
            <snapshots>
                <enabled>true</enabled>
            </snapshots>
            <id>ias-snapshots</id>
            <name>Infinite Automation Snapshot Repository</name>
            <url>https://maven.mangoautomation.net/repository/ias-snapshot/</url>
        </repository>
        <repository>
            <releases>
                <enabled>true</enabled>
            </releases>
            <snapshots>
                <enabled>false</enabled>
            </snapshots>
            <id>ias-releases</id>
            <name>Infinite Automation Release Repository</name>
            <url>https://maven.mangoautomation.net/repository/ias-release/</url>
        </repository>
    </repositories>
    <dependencies>
        <!-- 串口通信  begin-->
        <!-- https://mvnrepository.com/artifact/org.rxtx/rxtx -->
        <dependency>
            <groupId>org.rxtx</groupId>
            <artifactId>rxtx</artifactId>
            <version>2.1.7</version>
        </dependency>
        <!-- https://mvnrepository.com/artifact/org.scream3r/jssc -->
        <dependency>
            <groupId>org.scream3r</groupId>
            <artifactId>jssc</artifactId>
            <version>2.8.0</version>
        </dependency>
        <dependency>
            <groupId>com.infiniteautomation</groupId>
            <artifactId>modbus4j</artifactId>
            <version>3.0.3</version>
        </dependency>
        <!-- 串口通信  end-->
        <dependency>
            <groupId>org.apache.commons</groupId>
            <artifactId>commons-lang3</artifactId>
            <version>3.7</version>
        </dependency>
        <dependency>
            <groupId>org.slf4j</groupId>
            <artifactId>slf4j-log4j12</artifactId>
            <version>1.7.25</version>
        </dependency>
    </dependencies>
</project>

5、主調用程序

package com.dj.collection;

import java.util.Arrays;
import com.serotonin.modbus4j.ModbusFactory;
import com.serotonin.modbus4j.ModbusMaster;
import com.serotonin.modbus4j.exception.ModbusInitException;
import com.serotonin.modbus4j.exception.ModbusTransportException;
import com.serotonin.modbus4j.msg.ReadHoldingRegistersRequest;
import com.serotonin.modbus4j.msg.ReadHoldingRegistersResponse;
import com.serotonin.modbus4j.serial.SerialPortWrapper;

/**
 * 通過串口解析MODBUS協議
 * @author yaohj
 */
public class CollectionMain {
    // 設定MODBUS網絡上從站地址
    private final static int SLAVE_ADDRESS = 1;
    //串行波特率
    private final static int BAUD_RATE = 9600;

    public static void main(String[] args) {
        SerialPortWrapper serialParameters = new
                SerialPortWrapperImpl("COM2", BAUD_RATE, 8, 1, 0, 0, 0);
        /* 創建ModbusFactory工廠實例 */
        ModbusFactory modbusFactory = new ModbusFactory();
        /* 創建ModbusMaster實例 */
        ModbusMaster master = modbusFactory.createRtuMaster(serialParameters);
        /* 初始化 */
        try {
            master.init();
            readHoldingRegistersTest(master, SLAVE_ADDRESS, 99, 24);
        } catch (ModbusInitException e) {
            e.printStackTrace();
        } finally {
            master.destroy();
        }
    }

    /**
     * 讀保持寄存器上的內容
     * @param master 主站
     * @param slaveId 從站地址
     * @param start 起始地址的偏移量
     * @param len 待讀寄存器的個數
     */
    private static void readHoldingRegistersTest(ModbusMaster master, int slaveId, int start, int len) {
        try {
            ReadHoldingRegistersRequest request = new ReadHoldingRegistersRequest(slaveId, start, len);
            ReadHoldingRegistersResponse response = (ReadHoldingRegistersResponse)master.send(request);
            if (response.isException()) {
                System.out.println("Exception response: message=" + response.getExceptionMessage());
            } else {
                System.out.println(Arrays.toString(response.getShortData()));
                short[] list = response.getShortData();
                for (int i = 0; i < list.length; i++) {
                    System.out.print(list[i] + " ");
                }
            }
        } catch (ModbusTransportException e) {
            e.printStackTrace();
        }
    }
}

6、執行結果

正確的取回了值，使用起來相當方便