J2Mod - I/O异常 - 读取失败

在处理J2Mod库中的I/O异常和读取失败问题时，可以参考以下示例代码来解决问题：

import io.netty.channel.ChannelException;
import io.netty.channel.ChannelHandlerContext;
import io.netty.channel.ChannelInboundHandlerAdapter;
import io.netty.channel.ChannelOption;
import io.netty.channel.ChannelPipeline;
import io.netty.channel.SimpleChannelInboundHandler;
import io.netty.handler.codec.ByteToMessageDecoder;
import io.netty.handler.codec.DelimiterBasedFrameDecoder;
import io.netty.handler.codec.Delimiters;
import io.netty.handler.codec.MessageToByteEncoder;
import io.netty.handler.codec.string.StringDecoder;
import io.netty.handler.codec.string.StringEncoder;
import io.netty.handler.timeout.IdleStateEvent;
import io.netty.handler.timeout.IdleStateHandler;
import org.apache.logging.log4j.LogManager;
import org.apache.logging.log4j.Logger;
import org.openmuc.j2mod.Modbus;
import org.openmuc.j2mod.ModbusIOException;
import org.openmuc.j2mod.io.ModbusRTUTCPMaster;
import org.openmuc.j2mod.io.ModbusTCPTransaction;
import org.openmuc.j2mod.modbus.ModbusException;
import org.openmuc.j2mod.modbus.msg.*;
import org.openmuc.j2mod.modbus.net.TCPMasterConnection;
import org.openmuc.j2mod.modbus.procimg.SimpleRegister;

import java.io.IOException;
import java.net.InetAddress;
import java.net.UnknownHostException;
import java.util.List;
import java.util.concurrent.TimeUnit;

public class ModbusTcpMasterExample {

    private static final Logger logger = LogManager.getLogger(ModbusTcpMasterExample.class);

    private static final int TRANSACTION_ID = 0;
    private static final int RETRIES = 3;
    private static final int TIMEOUT = 100;

    public static void main(String[] args) {
        ModbusTCPTransaction transaction;
        ModbusRequest request;
        ModbusResponse response;

        try {
            ModbusRTUTCPMaster master = new ModbusRTUTCPMaster(InetAddress.getLocalHost().getHostAddress(), 502);
            master.setRetries(RETRIES);
            master.setTimeout(TIMEOUT);
            master.connect();

            transaction = master.getTransaction();
            transaction.setRetries(RETRIES);
            transaction.setReconnecting(false);

            request = new ReadCoilsRequest(0, 10);
            transaction.setRequest(request);
            transaction.execute();
            response = transaction.getResponse();

            if (response.isException()) {
                logger.error("Modbus exception response received: " + response.getExceptionMessage());
            } else {
                ReadCoilsResponse readCoilsResponse = (ReadCoilsResponse) response;
                boolean[] coils = readCoilsResponse.getBooleanData();
                for (int i = 0; i < coils.length; i++) {
                    logger.info("Coil " + i + ": " + coils[i]);
                }
            }

            master.disconnect();
        } catch (UnknownHostException e) {
            logger.error("Unknown host", e);
        } catch (ModbusIOException e) {
            logger.error("Modbus I/O exception", e);
        } catch (ModbusException e) {
            logger.error("Modbus exception", e);
        }
    }
}

此示例代码展示了如何使用J2Mod库中的ModbusRTUTCPMaster类进行Modbus TCP通信。在此示例中，使用了ReadCoilsRequest来读取线圈状态，并通过ReadCoilsResponse获取响应。

当出现I/O异常或读取失败时，该代码会捕获并打印相应的错误信息。您可以根据实际需求进行处理或记录日志。

请注意，此示例代码假设您已经正确配置了Modbus TCP从站设备，并且能够通过指定的IP地址和端口进行通信。

希望这个示例能够帮助您解决J2Mod库中的I/O异常和读取失败问题。