java - 在 AsynchronousSocketChannel Reas/Connection Handler 中找不到符号

Question

这个问题已经有答案了:

What does a "Cannot find symbol" or "Cannot resolve symbol" error mean? (18 个回答)

已关闭 4 年前。

我正在尝试通过 AsynchronousSocketChannel 使用 Java 在 Android 中开发 TCP/IP 通信应用程序。我在读取处理程序中收到私有(private)数据成员的符号未找到错误。我之前没有 Android 应用程序开发或 Java 方面的经验，但我在 C++ 领域工作过很多。该程序基于 C++ Boost.Asio 应用程序的模板，该应用程序运行正常。操作系统 - Windows 10 64 位目标平台 - Android Things Raspberry Pi 1.08

public class Ethernet {
    private String                      ip;
    private int                         portNo;
    private Queue<String>               recvQueue, sendQueue;
    private InetAddress                 address;
    private String                      readData;
    private InputStream                 in;
    private OutputStream                out;
    private AsynchronousSocketChannel   socket;
    private boolean                     socketAlive, connectionInProgress;
    private ByteBuffer                  readBuffer;

    Ethernet(String ip, int port) {
        if (port > 65535 && port < 1024)
            port = 6666;
        this.ip = ip;
        this.portNo = port;
        this.socketAlive = false;
        this.connectionInProgress = false;
        this.readBuffer = ByteBuffer.allocate(8192);
    }

    private void recieveDataSocket(){
        this.socket.read(this.readBuffer, null, new CompletionHandler<Integer, Object>() {
            @Override
            public void completed(Integer result, Object attachment) {
                if (result < 0) {
                    this.socketAlive = false;  //Error
                }
                else if (this.readBuffer.remaining() > 0) {
                    // repeat the call with the same CompletionHandler
                    this.socket.read(this.readBuffer, null, this);//Error
                }
                else {
                    // got all data, process the buffer
                }
            }
            @Override
            public void failed(Throwable e, Object attachment) {
                // handle the failure
            }
        });
    } }

Error :

error: cannot find symbol
this.socketAlive = false;
^  symbol: variable socketAlive  error: cannot find symbol
else if (this.readBuffer.remaining() > 0) {
^  symbol: variable readBuffer  error: cannot find symbol
this.socket.read(this.readBuffer, null, this);
^   symbol: variable readBuffer   error: cannot find symbol
this.socket.read(this.readBuffer, null, this);
 ^   symbol: variable socket   error: cannot find symbol
eth.disconnect();
^   symbol:   method disconnect()   location: variable eth of type Ethernet 5 errors

Answer 1

在错误发生时，this 指的是您使用 new CompletionHandler ... 创建的匿名类，并且该类没有成员 socketAlive .

要解决这个问题，只需省略 this.。