int read（byte[] b, int off, int len）

描述 (Description)

java.util.zip.DeflaterInputStream.read(byte[] b, int off, int len)方法从输入流中读取单个字节的压缩数据。 此方法将阻塞，直到可以读取和压缩某些输入。

声明 (Declaration)

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

public int read(byte[] b, int off, int len)
   throws IOException

参数 (Parameters)

• b - 读取数据的缓冲区。

• off - b内数据的起始偏移量。

• len - 要读入的最大压缩字节数b。

返回值 (Returns)

读取的实际字节数，如果到达未压缩输入流的末尾，则返回-1。

异常 (Exceptions)

• IndexOutOfBoundsException - 如果len“b.length - off。

• IOException - 如果发生I/O错误或此流已关闭。

例子 (Example)

以下示例显示了java.util.zip.DeflaterInputStream.read（byte [] b，int off，int len）方法的用法。

package cn.xnip;
import java.io.ByteArrayInputStream;
import java.io.IOException;
import java.util.zip.DataFormatException;
import java.util.zip.Deflater;
import java.util.zip.InflaterInputStream;
public class DeflaterInputStreamDemo {
   public static void main(String[] args) throws DataFormatException, IOException {
      String message = "Welcome to xnip.cn;"
         +"Welcome to xnip.cn;"
         +"Welcome to xnip.cn;"
         +"Welcome to xnip.cn;"
         +"Welcome to xnip.cn;"
         +"Welcome to xnip.cn;"
         +"Welcome to xnip.cn;"
         +"Welcome to xnip.cn;"
         +"Welcome to xnip.cn;"
         +"Welcome to xnip.cn;";
      System.out.println("Original Message length : " + message.length());
      byte[] input = message.getBytes("UTF-8");
      int length = message.length();
      // 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.NO_FLUSH);
      System.out.println("Total uncompressed bytes input :" + deflater.getTotalIn());
      System.out.println("Compressed Message Checksum :" + deflater.getAdler());     
      deflater.finished();
      System.out.println("Compressed Message length : " + compressedDataLength);
      ByteArrayInputStream bin = new ByteArrayInputStream(output);
      InflaterInputStream inflaterInputStream = new InflaterInputStream(bin);
      byte[] result = new byte[1024];
      inflaterInputStream.read(result,0,result.length);
      inflaterInputStream.close();
      // Decode the bytes into a String
      String message1 = new String(result,0, length,"UTF-8");
      System.out.println(message.equals(message1));
   }
}

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
Total uncompressed bytes input :300
Compressed Message Checksum :368538129
Compressed Message length : 42
true