Java Java.util.zip.DeflaterInputStream用法及代码示例

实现输入流过滤器，用于以 “deflate” 压缩格式压缩数据。

构造函数和说明

• DeflaterInputStream(输入流中)：使用默认压缩器和缓冲区大小创建新的输入流。
• DeflaterInputStream(InputStream in, Deflater defl):使用指定的压缩器和默认缓冲区大小创建新的输入流。
• DeflaterInputStream(InputStream in, Deflater defl, int bufLen) :使用指定的压缩器和缓冲区大小创建新的输入流。

方法：

• int available()：到达 EOF 后返回 0，否则始终返回 1。

  Syntax :public int available()
                throws IOException
  Parameters:
  n - number of bytes to be skipped
  返回：
  the actual number of bytes skipped
  Throws:
  IOException

• 无效close()：关闭此输入流及其底层输入流，丢弃任何挂起的未压缩数据。

  Syntax :public void close()
             throws IOException
  Overrides:
  close in class FilterInputStream
  Throws:
  IOException

• 无效标记(int limit)：不支持该操作。

  Syntax :public void mark(int limit)
  参数：
  limit - maximum bytes that can be read before invalidating the position marker
  

• 布尔值markSupported()：始终返回 false，因为此输入流不支持 mark() 和 reset() 方法。

  Syntax :public boolean markSupported()
  返回：
  false, always

• int read()：从输入流读取单个字节的压缩数据。

  Syntax :public int read()
           throws IOException
  返回：
  a single byte of compressed data, or -1 if the end of the uncompressed
  input stream is reached
  Throws:
  IOException

• int 读取(字节[] b，int 关闭，int len)：将压缩数据读入字节数组。

  Syntax :public int read(byte[] b,
         int off,
         int len)
           throws IOException
  Parameters:
  b - buffer into which the data is read
  off - starting offset of the data within b
  len - maximum number of compressed bytes to read into b
  返回：
  the actual number of bytes read, or -1 if the end of the
  uncompressed input stream is reached
  Throws:
  IndexOutOfBoundsException 
  IOException 

• 无效reset()：不支持该操作。

  Syntax :public void reset()
             throws IOException
  Throws:
  IOException

• 长跳过(长n)：跳过并丢弃输入流中的数据。

  Syntax :public long skip(long n)
            throws IOException
  参数：
  n - number of bytes to be skipped
  返回：
  the actual number of bytes skipped
  Throws:
  IOException

程序：

//Java program to illustrate DeflaterInputStream class 
import java.io.ByteArrayInputStream; 
import java.io.IOException; 
import java.util.zip.DeflaterInputStream; 
  
class DeflaterInputStreamDemo 
{ 
    public static void main(String[] args) throws IOException 
    { 
        byte b[] = new byte[10]; 
        for (byte i = 0; i <10 ; i++) 
        { 
            b[i] = i; 
        } 
        ByteArrayInputStream bin = new ByteArrayInputStream(b); 
        DeflaterInputStream din = new DeflaterInputStream(bin); 
  
        //illustrating markSupported() method 
        System.out.println(din.markSupported()); 
          
        //illustrating skip() method 
        din.skip(1); 
  
        //illustrating available() method 
        System.out.println(din.available()); 
  
        //illustrating read(byte[] b,int off,int len) 
        byte c[] = new byte[10]; 
          
        din.read(c,0,9); 
                for (int i = 0; i < 9; i++) 
        { 
            System.out.print(c[i]); 
        } 
        while(din.available() == 1) 
        { 
            //Reads a single byte of compressed data 
            System.out.print(din.read()); 
        } 
          
        System.out.println(); 
        System.out.println(din.available()); 
  
        // illustrating close() method 
        din.close(); 
    } 
} 

输出：

false
1
-1009996100981029710199231224400175046-1
0

上面的输出表示压缩数据。

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