java bytebuffer flip_java string转byte

import java.nio.ByteBuffer;  
import java.nio.ByteOrder;  
public class bytebuffertest {  
public static void main(String[] args)  
{  
// Create a ByteBuffer using a byte array   
byte[] bytes = new byte[10];  
ByteBuffer buf = ByteBuffer.wrap(bytes);  
// Create a non-direct ByteBuffer with a 10 byte capacity   
// The underlying storage is a byte array.   
buf = ByteBuffer.allocate(10);  
// Create a direct (memory-mapped) ByteBuffer with a 10 byte capacity.   
buf = ByteBuffer.allocateDirect(10);  
// Create an empty ByteBuffer with a 10 byte capacity   
ByteBuffer bbuf = ByteBuffer.allocate(10);  
// Get the ByteBuffer's capacity   
int capacity = bbuf.capacity(); // 10   
System.out.println(capacity);  
// Use the absolute get().   
// This method does not affect the position.   
byte b = bbuf.get(5); // position=0   
// Set the position   
bbuf.position(5);  
// Use the relative get()   
b = bbuf.get();  
// Get the new position   
int pos = bbuf.position(); // 6   
// Get remaining byte count   
int rem = bbuf.remaining(); // 4   
// Set the limit   
bbuf.limit(7); // remaining=1   
// This convenience method sets the position to 0   
bbuf.rewind(); // remaining=7   
//Converting Between a ByteBuffer an a Byte Array    
// Create a ByteBuffer from a byte array   
byte[] bytes1 = new byte[10];  
ByteBuffer buf1 = ByteBuffer.wrap(bytes);  
// Retrieve bytes between the position and limit   
// (see Putting Bytes into a ByteBuffer)   
bytes1 = new byte[buf.remaining()];  
buf1.get(bytes1, 0, bytes1.length);  
// Retrieve all bytes in the buffer   
buf1.clear();  
bytes1 = new byte[buf1.capacity()];  
buf1.get(bytes1, 0, bytes1.length);  
// Use the absolute put().   
// This method does not affect the position.   
bbuf.put((byte)0xFF); // position=0   
// Set the position   
bbuf.position(5);  
// Use the relative put()   
bbuf.put((byte)0xFF);  
// Get the new position   
int pos1 = bbuf.position(); // 6   
//Setting the Byte Ordering for a ByteBuffer    
// Get default byte ordering   
ByteOrder order = buf.order(); // ByteOrder.BIG_ENDIAN   
// Put a multibyte value   
buf.putShort(0, (short)123);  
buf.get(0); // 0   
buf.get(1); // 123   
// Set to little endian   
buf.order(ByteOrder.LITTLE_ENDIAN);  
// Put a multibyte value   
buf.putShort(0, (short)123);  
buf.get(0); // 123   
buf.get(1); // 0   
}  
}