极客教程Java ByteBuffer order()方法及示例
order()
java.nio.ByteBuffer 类的 order() 方法是用来检索这个缓冲区的字节顺序。在读取或写入多字节值时，以及在创建作为该字节缓冲区的视图的缓冲区时，都会用到该字节顺序。新创建的字节缓冲区的顺序总是BIG_ENDIAN。
语法
public final ByteOrder order()
返回值： 该方法返回这个缓冲区的字节顺序。
下面是说明order()方法的例子。
例子 1 :
// Java program to demonstrate
// order() method
import java.nio.*;
import java.util.*;
public class GFG {
public static void main(String[] args)
{
// creating object of ByteBuffer
// and allocating size capacity
ByteBuffer bb = ByteBuffer.allocate(12);
// putting the int value in the bytebuffer
bb.asIntBuffer()
.put(10)
.put(20)
.put(30);
// rewind the Bytebuffer
bb.rewind();
// print the ByteBuffer
System.out.println("Original ByteBuffer: ");
for (int i = 1; i <= 3; i++)
System.out.print(bb.getInt() + " ");
// rewind the Bytebuffer
bb.rewind();
// Reads the Int at this buffer's current position
// using order() method
ByteOrder value = bb.order();
// print the int value
System.out.println("\n\nByte Value: " + value);
}
}
输出。
Original ByteBuffer:
10 20 30
Byte Value: BIG_ENDIAN
例子 2 :
// Java program to demonstrate
// order() method
import java.nio.*;
import java.util.*;
public class GFG {
public static void main(String[] args)
{
// creating object of ByteBuffer
// and allocating size capacity
ByteBuffer bb = ByteBuffer.allocate(12);
// Reads the Int at this buffer's current position
// using order() method
ByteOrder value = bb.order();
// print the int value
System.out.println("Byte Value: " + value);
}
}
输出。
Byte Value: BIG_ENDIAN
order(ByteOrder bo)
ByteBuffer的order(ByteOrder bo)方法是用来修改这个缓冲区的字节顺序。
语法
public final ByteBuffer order(ByteOrder bo)
参数： 该方法接受新的字节顺序，BIG_ENDIAN或LITTLE_ENDIAN作为参数。
返回值： 该方法返回该缓冲区。
下面是说明order(ByteOrder bo)方法的例子。
例子 1 :
// Java program to demonstrate
// order() method
import java.nio.*;
import java.util.*;
public class GFG {
public static void main(String[] args)
{
// creating object of ByteBuffer
// and allocating size capacity
ByteBuffer bb = ByteBuffer.allocate(12);
// Reads the Int at this buffer's current position
// using order() method
ByteOrder oldbyteorder = bb.order();
// print the result
System.out.println("Old Byte Order: " + oldbyteorder);
// Modifies this buffer's byte order
// by using order() method
ByteBuffer bb1 = bb.order(ByteOrder.nativeOrder());
// Reads the Int at this buffer's current position
// using order() method
ByteOrder newbyteorder = bb1.order();
// print the result
System.out.println("New Byte Order: " + newbyteorder);
}
}
输出。
Old Byte Order: BIG_ENDIAN
New Byte Order: LITTLE_ENDIAN
例子 2 :
// Java program to demonstrate
// order() method
import java.nio.*;
import java.util.*;
public class GFG {
public static void main(String[] args)
{
// creating object of ByteBuffer
// and allocating size capacity
ByteBuffer bb = ByteBuffer.allocate(12);
// putting the int value in the bytebuffer
bb.asIntBuffer()
.put(10)
.put(20)
.put(30);
// rewind the Bytebuffer
bb.rewind();
// print the ByteBuffer
System.out.println("Original ByteBuffer: ");
for (int i = 1; i <= 3; i++)
System.out.print(bb.getInt() + " ");
// rewind the Bytebuffer
bb.rewind();
// Reads the Int at this buffer's current position
// using order() method
ByteOrder oldbyteorder = bb.order();
// print the result
System.out.println("Old Byte Order: " + oldbyteorder);
// Modifies this buffer's byte order
// by using order() method
ByteBuffer bb1 = bb.order(ByteOrder.nativeOrder());
// Reads the Int at this buffer's current position
// using order() method
ByteOrder newbyteorder = bb1.order();
// print the result
System.out.println("New Byte Order: " + newbyteorder);
}
}
输出。
Original ByteBuffer:
10 20 30 Old Byte Order: BIG_ENDIAN
New Byte Order: LITTLE_ENDIAN
参考资料。
- https://docs.oracle.com/javase/9/docs/api/java/nio/ByteBuffer.html#order-
- https://docs.oracle.com/javase/9/docs/api/java/nio/ByteBuffer.html#order-java.nio.ByteOrder-