java.util.zip.Inflater.needsInput()方法示例

java.util.zip.Inflater.needsInput()方法如果輸入緩衝區中沒有數據則返回true。 這可以用來確定是否應該調用setInput()以提供更多輸入。

聲明

以下是java.util.zip.Inflater.needsInput()方法的聲明。

public boolean needsInput()

參數

• N/A

返回值

• 如果輸入緩衝區中沒有數據，則為true。

異常

• N/A

示例

以下示例顯示了java.util.zip.Inflater.needsInput()方法的用法。

package com.zaixian;

import java.io.UnsupportedEncodingException;
import java.util.zip.DataFormatException;
import java.util.zip.Deflater;
import java.util.zip.Inflater;

public class InflaterDemo {
   public static void main(String[] args)
      throws DataFormatException, UnsupportedEncodingException {
      String message = "Welcome to xuhuhu.com;"
         +"Welcome to xuhuhu.com;"
         +"Welcome to xuhuhu.com;"
         +"Welcome to xuhuhu.com;"
         +"Welcome to xuhuhu.com;"
         +"Welcome to xuhuhu.com;"
         +"Welcome to xuhuhu.com;"
         +"Welcome to xuhuhu.com;"
         +"Welcome to xuhuhu.com;"
         +"Welcome to xuhuhu.com;";
      System.out.println("Original Message length : " + message.length());
      byte[] input = message.getBytes("UTF-8");

      // Compress the bytes
      byte[] output = new byte[1024];
      Deflater deflater = new Deflater();
      deflater.setInput(input);
      deflater.finish();
      int compressedDataLength = deflater.deflate(output,0,output.length);
      deflater.end();

      System.out.println("Compressed Message length : " + compressedDataLength);

      // Decompress the bytes
      Inflater inflater = new Inflater();
      inflater.setInput(output, 0, 10);
      byte[] result = new byte[1024];
      int resultLength = inflater.inflate(result, 0 , 10);

      if(inflater.needsInput()){
         inflater.setInput(output, 10, compressedDataLength - resultLength);
         resultLength += inflater.inflate(result, resultLength , result.length - resultLength);
      }

      inflater.end();

      // Decode the bytes into a String
      message = new String(result, 0, resultLength, "UTF-8");

      System.out.println("UnCompressed Message length : " + message.length());
   }
}

執行上面示例代碼，得到以下結果 -

Original Message length : 300
Compressed Message length : 42
UnCompressed Message length : 300