Java java.util.zip.GZIPOutputStream.finish()用法及代码示例

描述

这个java.util.zip.GZIPOutputStream.finish()方法完成将压缩数据写入输出流而不关闭底层流。将多个过滤器连续应用于同一输出流时，请使用此方法。

声明

以下是声明java.util.zip.GZIPOutputStream.finish()方法。

public void finish()
   throws IOException

异常

• IOException- 如果发生了 I/O 错误。

示例

下面的例子展示了 java.util.zip.GZIPOutputStream.finish() 方法的用法。

package com.tutorialspoint;

import java.io.ByteArrayInputStream;
import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.util.Arrays;
import java.util.zip.DataFormatException;
import java.util.zip.GZIPInputStream;
import java.util.zip.GZIPOutputStream;

public class GZIPOutputStreamDemo {

   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");

      // Compress the bytes
      ByteArrayOutputStream arrayOutputStream = new ByteArrayOutputStream();
      GZIPOutputStream outputStream = new GZIPOutputStream(arrayOutputStream);
      outputStream.write(input);
      outputStream.finish();
      outputStream.close();

      //Read and decompress the data
      byte[] readBuffer = new byte[5000];
      ByteArrayInputStream arrayInputStream = 
         new ByteArrayInputStream(arrayOutputStream.toByteArray());
      GZIPInputStream inputStream = new GZIPInputStream(arrayInputStream);
      int read = inputStream.read(readBuffer,0,readBuffer.length);
      inputStream.close();
      //Should hold the original (reconstructed) data
      byte[] result = Arrays.copyOf(readBuffer, read);

      // Decode the bytes into a String
      message = new String(result, "UTF-8");
    
      System.out.println("UnCompressed Message length:" + message.length());
   }
}

让我们编译并运行上面的程序，这将产生以下结果——

Original Message length:300
UnCompressed Message length:300