的Java約@覆蓋

Question

那麼，什麼是與覆蓋我不的問題得到它：

@Override 
public ProtocolEncoder getEncoder(IoSession session) throws Exception { 
    return encoder; 
} 
@Override 
public ProtocolDecoder getDecoder(IoSession session) throws Exception { 
    return decoder; 
} 

錯誤：

error: method does not override or implement a method from a supertype 
@Override 

error: MaplePacketDecoder is not abstract and does not override abstract method doDecode(IoSession,ByteBuffer,ProtocolDecoderOutput) in CumulativeProtocolDecoder 
public class MaplePacketDecoder extends CumulativeProtocolDecoder { 

error: method write in interface ProtocolEncoderOutput cannot be applied to given types; 
       out.write(IoBuffer.wrap(ret)); 
    required: ByteBuffer 
    found: IoBuffer 
    reason: actual argument IoBuffer cannot be converted to ByteBuffer by method invocation conversion 

Answer 1

你忘了執行doDecode(IoSession,ByteBuffer,ProtocolDecoderOutput)。

Answer 2

看來，您嘗試覆蓋的方法名稱或您提供的參數不正確。你也不要從CumulativeProtocolDecoder實現doDecode方法。如果CumulativeProtocolDecoder是一個抽象類，您應該實現它。

Answer 3

你試圖用不同的參數（不同的簽名）覆蓋超類中的方法。重寫的方法必須匹配被覆蓋的方法的簽名（在父類中）。

http://docs.oracle.com/javase/tutorial/java/IandI/override.html