java.util.zip.DeflaterInputStream.available() 方法示例

說明

當已達到 EOF 後，java.util.zip.DeflaterInputStream.available() 方法返回 0，否則始終返回 1。

宣告

以下是 java.util.zip.DeflaterInputStream.available() 方法的宣告。

public int available()
   throws IOException

返回

當已達到基礎輸入流的末尾後為零，否則始終返回 1。

異常

• IOException − 如果發生 I/O 錯誤或此流已關閉。

示例

以下示例展示了 java.util.zip.DeflaterInputStream.available() 方法的使用。

package com.tutorialspoint;

import java.io.ByteArrayInputStream;
import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.util.zip.DataFormatException;
import java.util.zip.Deflater;
import java.util.zip.InflaterInputStream;

public class DeflaterInputStreamDemo {
   public static void main(String[] args) throws DataFormatException, IOException {
      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");
      int length = message.length();
      // 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.NO_FLUSH);
      System.out.println("Total uncompressed bytes input :" + deflater.getTotalIn());
      System.out.println("Compressed Message Checksum :" + deflater.getAdler());     
      deflater.finished();

      System.out.println("Compressed Message length : " + compressedDataLength);
   
      ByteArrayInputStream bin = new ByteArrayInputStream(output);
      InflaterInputStream inflaterInputStream = new InflaterInputStream(bin);
      byte[] result = new byte[1024];

      ByteArrayOutputStream buffer = new ByteArrayOutputStream();
      while(inflaterInputStream.available() != 0){
         buffer.write(inflaterInputStream.read());
      }

      inflaterInputStream.close();
      // Decode the bytes into a String
      String message1 = new String(buffer.toByteArray(),0, length,"UTF-8");
      System.out.println(message.equals(message1));
   }
}

我們編譯並執行上述程式，這樣會生成以下結果 −

Original Message length : 300
Total uncompressed bytes input :300
Compressed Message Checksum :368538129
Compressed Message length : 42
true