Java java.util.zip.DeflaterInputStream.read()用法及代碼示例

描述

這個java.util.zip.DeflaterInputStream.read(byte[] b, int off, int len)方法從輸入流中讀取一個字節的壓縮數據。此方法將阻塞，直到可以讀取和壓縮某些輸入。

聲明

以下是聲明java.util.zip.DeflaterInputStream.read(byte[] b, int off, int len)方法。

public int read(byte[] b, int off, int len)
   throws IOException

參數

• b- 讀取數據的緩衝區。

• off- b 內數據的起始偏移量。

• len- 要讀入 b 的最大壓縮字節數。

返回

讀取的實際字節數，如果到達未壓縮輸入流的末尾，則為 -1。

異常

• IndexOutOfBoundsException - 如果 len > b.length - 關閉。

• IOException - 如果發生 I/O 錯誤或此流已關閉。

示例

下麵的例子展示了 java.util.zip.DeflaterInputStream.read(byte[] b, int off, int len) 方法的用法。

package com.tutorialspoint;

import java.io.ByteArrayInputStream;
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];

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

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