Java java.util.zip.Deflater.deflate()用法及代码示例

描述

这个java.util.zip.Deflater.deflate(byte[] b, int off, int len)方法压缩输入数据并用压缩数据填充指定的缓冲区。返回压缩数据的实际字节数。返回值 0 表示应调用 NeedInput 以确定是否需要更多输入数据。

声明

以下是声明java.util.zip.Deflater.deflate(byte[] b, int off, int len)方法。

public int deflate(byte[] b, int off, int len)

参数

• b- 压缩数据的缓冲区。

• off− 数据的起始偏移量。

• len− 压缩数据的最大字节数。

返回

写入输出缓冲区的压缩数据的实际字节数。

示例

下面的例子展示了 java.util.zip.Deflater.deflate(byte[] b, int off, int len) 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 DeflaterDemo {
   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, compressedDataLength);
      byte[] result = new byte[1024];
      int resultLength = inflater.inflate(result);
      inflater.end();

      // Decode the bytes into a String
      message = new String(result, 0, resultLength, "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
Compressed Message length:42
UnCompressed Message length:300