Java java.util.zip.Inflater.needsInput()用法及代碼示例

描述

這個java.util.zip.Inflater.needsInput()如果輸入緩衝區中沒有剩餘數據，則方法返回 true。這可用於確定是否應調用 #setInput 以提供更多輸入。

聲明

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

public boolean needsInput()

返回

如果輸入緩衝區中沒有剩餘數據，則為 true。

示例

下麵的例子展示了 java.util.zip.Inflater.needsInput() 方法的用法。

package com.tutorialspoint;

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 TutorialsPoint.com;"
         +"Welcome to TutorialsPoint.com;"
         +"Welcome to TutorialsPoint.com;"
         +"Welcome to TutorialsPoint.com;"
         +"Welcome to TutorialsPoint.com;"
         +"Welcome to TutorialsPoint.com;"
         +"Welcome to TutorialsPoint.com;"
         +"Welcome to TutorialsPoint.com;"
         +"Welcome to TutorialsPoint.com;"
         +"Welcome to TutorialsPoint.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());
   }
}

讓我們編譯並運行上麵的程序，這將產生以下結果——

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