写一个MODBUS-TCP的java示例代码

好的，以下是一个简单的MODBUS-TCP的java示例代码：

import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.net.InetAddress;
import java.net.Socket;

public class ModbusTCPExample {

    // Modbus TCP通信参数
    private static final int SERVER_PORT = 502;
    private static final InetAddress SERVER_ADDRESS = InetAddress.getByName("127.0.0.1");

    // Modbus TCP指令
    private static final byte[] READ_COILS = { 0x00, 0x01, 0x00, 0x00, 0x00, 0x06, 0x01, 0x01, 0x00, 0x00, 0x00, 0x08 };
    private static final byte[] READ_INPUTS = { 0x00, 0x02, 0x00, 0x00, 0x00, 0x06, 0x01, 0x02, 0x00, 0x00, 0x00, 0x08 };
    private static final byte[] READ_HOLDING_REGISTERS = { 0x00, 0x03, 0x00, 0x00, 0x00, 0x06, 0x01, 0x03, 0x00, 0x00, 0x00, 0x08 };
    private static final byte[] READ_INPUT_REGISTERS = { 0x00, 0x04, 0x00, 0x00, 0x00, 0x06, 0x01, 0x04, 0x00, 0x00, 0x00, 0x08 };
    private static final byte[] WRITE_SINGLE_COIL = { 0x00, 0x05, 0x00, 0x00, 0x00, 0x06, 0x01, 0x05, 0x00, (byte) 0xFF, 0x00, 0x00 };
    private static final byte[] WRITE_SINGLE_REGISTER = { 0x00, 0x06, 0x00, 0x00, 0x00, 0x06, 0x01, 0x06, 0x00, 0x00, 0x00, 0x00 };

    public static void main(String[] args) {

        // 建立Socket连接
        try (Socket socket = new Socket(SERVER_ADDRESS, SERVER_PORT)) {

            // 获取输入输出流
            InputStream in = socket.getInputStream();
            OutputStream out = socket.getOutputStream();

            // 读取线圈状态
            byte[] response = ModbusTCPUtils.sendRequest(READ_COILS, in, out);
            boolean[] coils = ModbusTCPUtils.parseCoils(response, READ_COILS.length);

            // 读取输入状态
            response = ModbusTCPUtils.sendRequest(READ_INPUTS, in, out);
            boolean[] inputs = ModbusTCPUtils.parseInputs(response, READ_INPUTS.length);

            // 读取保持寄存器
            response = ModbusTCPUtils.sendRequest(READ_HOLDING_REGISTERS, in, out);
            int[] holdingRegisters = ModbusTCPUtils.parseRegisters(response, READ_HOLDING_REGISTERS.length / 2);

            // 读取输入寄存器
            response = ModbusTCPUtils.sendRequest(READ_INPUT_REGISTERS, in, out);
            int[] inputRegisters = ModbusTCPUtils.parseRegisters(response, READ_INPUT_REGISTERS.length / 2);

            // 写入单个线圈
            response = ModbusTCPUtils.sendRequest(WRITE_SINGLE_COIL, in, out);

            // 写入单个保持寄存器
            response = ModbusTCPUtils.sendRequest(WRITE_SINGLE_REGISTER, in, out);

        } catch (IOException e) {
            e.printStackTrace();
        }
    }
}

在这个示例代码中，我们使用了ModbusTCPUtils类来发送请求和解析响应。SEND_COILS、SEND_INPUTS、SEND_HOLDING_REGISTERS和SEND_INPUT_REGISTERS分别代表读取线圈、输入状态、保持寄存器和输入寄存器的指令。WRITE_SINGLE_COIL和WRITE_SINGLE_REGISTER分别代表写入单个线圈和保持寄存器的指令。