以下是一个示例代码，演示如何按行读取非阻塞的SocketChannel：

import java.io.IOException;
import java.nio.ByteBuffer;
import java.nio.channels.SocketChannel;

public class NonBlockingSocketReader {
    private static final int BUFFER_SIZE = 1024;

    public static void readLines(SocketChannel socketChannel) throws IOException {
        ByteBuffer buffer = ByteBuffer.allocate(BUFFER_SIZE);
        StringBuilder stringBuilder = new StringBuilder();

        int bytesRead;
        String line;

        while (true) {
            bytesRead = socketChannel.read(buffer);

            if (bytesRead == -1) {
                // 读取完毕，连接关闭
                break;
            }

            buffer.flip();

            while (buffer.hasRemaining()) {
                char c = (char) buffer.get();
                stringBuilder.append(c);

                if (c == '\n') {
                    line = stringBuilder.toString().trim();
                    System.out.println(line);
                    stringBuilder.setLength(0);
                }
            }

            buffer.clear();
        }
    }
}

使用上述代码，你可以调用readLines方法来按行读取非阻塞的SocketChannel。示例中的代码将读取到的每一行打印到控制台上。请注意，示例中使用了一个固定大小的ByteBuffer来读取数据，你可以根据需要调整缓冲区的大小。