java.util.zip.Inflater.needsInput() 方法

描述

如果输入缓冲区中没有数据，java.util.zip.Inflater.needsInput() 方法返回 true。 这可用于确定是否应调用 #setInput 以提供更多输入。

声明

以下是 java.util.zip.Inflater.needsInput() 方法的声明。

public boolean needsInput()

返回值

如果输入缓冲区中没有剩余数据，则为 true。

示例

下面的例子展示了 java.util.zip.Inflater.needsInput() 方法的使用。

package com.tutorialspoint;

import java.io.UnsupportedEncodingException;
import java.util.zip.DataFormatException;
import java.util.zip.Deflater;
import java.util.zip.Inflater;

public class InflaterDemo {
   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, 10);
      byte[] result = new byte[1024];
      int resultLength = inflater.inflate(result, 0 , 10);
      
      if(inflater.needsInput()){
         inflater.setInput(output, 10, compressedDataLength - resultLength);    
         resultLength += inflater.inflate(result, resultLength , result.length - resultLength);
      }

      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，这将产生下面的结果 −

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

❮ java.util.zip - Inflater 类