java.util.zip.Deflater.deflate() 方法示例

说明

java.util.zip.Deflater.deflate(byte[] b, int off, int len) 方法压缩输入数据并将指定的缓冲区填满压缩数据。返回压缩数据的实际字节数。返回值为 0 表示需要调用 needsInput 来确定是否需要更多输入数据。

声明

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

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

参数

• b − 压缩数据的缓冲区。

• off − 数据的开头偏移量。

• len − 压缩数据的最大字节数。

返回值

写入输出缓冲区的压缩数据的实际字节数。

示例

以下示例显示了如何使用 java.util.zip.Deflater.deflate(byte[] b, int off, int len) 方法。

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述程序，它将产生以下结果 −

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