我在以下代码中得到空指针异常：我已经看到上一个问题由另一个用户询问了nullpointer异常，但我对我的代码感到不舒服..请看看它..我编辑了我的问题..
package org.xiph.speex;
/**
* Main Speex Encoder class.
* This class encodes the given PCM 16bit samples into Speex packets.
*
* @author Marc Gimpel, Wimba S.A. (mgimpel@horizonwimba.com)
* @version $Revision: 1.6 $
*/
public class SpeexEncoder
{
/**
* Version of the Speex Encoder
*/
public static final String VERSION = "Java Speex Encoder v0.9.7 ($Revision: 1.6 $)";
private Encoder encoder;
private Bits bits;
private float[] rawData;
private int sampleRate;
private int channels;
private int frameSize;
/**
* Constructor
*/
public SpeexEncoder()
{
bits = new Bits();
}
/**
* Initialisation
* @param mode the mode of the encoder (0=NB, 1=WB, 2=UWB).
* @param quality the quality setting of the encoder (between 0 and 10).
* @param sampleRate the number of samples per second.
* @param channels the number of audio channels (1=mono, 2=stereo, ...).
* @return true if initialisation successful.
*/
public boolean init(final int mode,
final int quality,
final int sampleRate,
final int channels)
{
switch (mode) {
case 0:
encoder = new NbEncoder();
((NbEncoder)encoder).nbinit();
break;
//Wideband
case 1:
encoder = new SbEncoder();
((SbEncoder)encoder).wbinit();
break;
case 2:
encoder = new SbEncoder();
((SbEncoder)encoder).uwbinit();
break;
//*/
default:
return false;
}
/* initialize the speex decoder */
encoder.setQuality(quality);
/* set decoder format and properties */
this.frameSize = encoder.getFrameSize();
this.sampleRate = sampleRate;
this.channels = channels;
rawData = new float[channels*frameSize];
bits.init();
return true;
}
/**
* Returns the Encoder being used (Narrowband, Wideband or Ultrawideband).
* @return the Encoder being used (Narrowband, Wideband or Ultrawideband).
*/
public Encoder getEncoder()
{
return encoder;
}
/**
* Returns the sample rate.
* @return the sample rate.
*/
public int getSampleRate()
{
return sampleRate;
}
/**
* Returns the number of channels.
* @return the number of channels.
*/
public int getChannels()
{
return channels;
}
/**
* Returns the size of a frame.
* @return the size of a frame.
*/
public int getFrameSize()
{
return frameSize;
}
/**
* Pull the decoded data out into a byte array at the given offset
* and returns the number of bytes of encoded data just read.
* @param data
* @param offset
* @return the number of bytes of encoded data just read.
*/
public int getProcessedData(final byte[] data, final int offset)
{
int size = bits.getBufferSize();
System.arraycopy(bits.getBuffer(), 0, data, offset, size);
bits.init();
return size;
}
/**
* Returns the number of bytes of encoded data ready to be read.
* @return the number of bytes of encoded data ready to be read.
*/
public int getProcessedDataByteSize()
{
return bits.getBufferSize();
}
/**
* This is where the actual encoding takes place
* @param data
* @param offset
* @param len
* @return true if successful.
*/
public boolean processData(final byte[] data,
final int offset,
final int len)
{
// converty raw bytes into float samples
mapPcm16bitLittleEndian2Float(data, offset, rawData, 0, len/2);
// encode the bitstream
return processData(rawData, len/2);
}
/**
* Encode an array of shorts.
* @param data
* @param offset
* @param numShorts
* @return true if successful.
*/
public boolean processData(final short[] data,
final int offset,
final int numShorts)
{
int numSamplesRequired = channels * frameSize;
if (numShorts != numSamplesRequired) {
throw new IllegalArgumentException("SpeexEncoder requires " + numSamplesRequired + " samples to process a Frame, not " + numShorts);
}
// convert shorts into float samples,
for (int i=0; i<numShorts; i++) {
rawData[i] = (float) data[offset + i ];
}
// encode the bitstream
return processData(rawData, numShorts);
}
/**
* Encode an array of floats.
* @param data
* @param numSamples
* @return true if successful.
*/
public boolean processData(final float[] data, final int numSamples)
{
int numSamplesRequired = channels * frameSize;
if (numSamples != numSamplesRequired) {
throw new IllegalArgumentException("SpeexEncoder requires " + numSamplesRequired + " samples to process a Frame, not " + numSamples );
}
// encode the bitstream
if (channels==2) {
Stereo.encode(bits, data, frameSize);
}
encoder.encode(bits, data);
return true;
}
/**
* Converts a 16 bit linear PCM stream (in the form of a byte array)
* into a floating point PCM stream (in the form of an float array).
* Here are some important details about the encoding:
* <ul>
* <li> Java uses big endian for shorts and ints, and Windows uses little Endian.
* Therefore, shorts and ints must be read as sequences of bytes and
* combined with shifting operations.
* </ul>
* @param pcm16bitBytes - byte array of linear 16-bit PCM formated audio.
* @param offsetInput
* @param samples - float array to receive the 16-bit linear audio samples.
* @param offsetOutput
* @param length
*/
public static void mapPcm16bitLittleEndian2Float(final byte[] pcm16bitBytes,
final int offsetInput,
final float[] samples,
final int offsetOutput,
final int length)
{
if (pcm16bitBytes.length - offsetInput < 2 * length) {
throw new IllegalArgumentException("Insufficient Samples to convert to floats");
}
if (samples.length - offsetOutput < length) {
throw new IllegalArgumentException("Insufficient float buffer to convert the samples");
}
for (int i = 0; i < length; i++) {
samples[offsetOutput+i] = (float)((pcm16bitBytes[offsetInput+2*i] & 0xff) | (pcm16bitBytes[offsetInput+2*i+1] << 8)); // no & 0xff at the end to keep the sign
}
}
public void setDtx(boolean dtx) {
// TODO Auto-generated method stub
}
public void setVbrQuality(float vbr_quality) {
// TODO Auto-generated method stub
}
public void setVad(boolean vad) {
// TODO Auto-generated method stub
}
public void setComplexity(int complexity) {
// TODO Auto-generated method stub
}
public void setBitRate(int bitrate) {
// TODO Auto-generated method stub
}
}
我已经标记了发生异常的代码的所有语句。我无法处理这些代码中出现的空指针异常
答案 0 :(得分：2)
NullPointerExceptions的内容访问字段或方法，则会出现 null。
在您标记的行中，您尝试访问length的{{1}}属性。因此samples samples的可能性很高。