Java 中的缓冲数组()方法，示例
原文:https://www . geesforgeks . org/buffer-array-methods-in-Java-with-examples/
java.nio.Buffer 类的数组()方法用于返回支持所取缓冲区的数组。 此方法旨在允许数组支持的缓冲区更有效地传递给本机代码。具体的子类为此方法提供了更强类型的返回值。
对此缓冲区内容的修改将导致返回数组的内容被修改，反之亦然。在调用此方法之前，请调用 hasArray 方法，以确保此缓冲区具有可访问的后备数组。
语法:
public abstract Object array()
返回值:这个方法返回支持这个缓冲区的数组。
异常:如果此缓冲区由数组支持但为只读，则此方法将引发readonlybufferrexception。
下面是说明 array()方法的示例:
例 1:
// Java program to demonstrate
// array() method
import java.nio.*;
import java.util.*;
public class GFG {
public static void main(String[] args)
{
// Declaring the capacity of the ByteBuffer
int capacity = 4;
// Creating the ByteBuffer
try {
// creating object of ByteBuffer
// and allocating size capacity
ByteBuffer bb = ByteBuffer.allocate(capacity);
// putting the int to byte typecast
// value in ByteBuffer
bb.put((byte)20);
bb.put((byte)30);
bb.put((byte)40);
bb.put((byte)50);
// Typecasting ByteBuffer into Buffer
Buffer bb1 = (Buffer)bb;
// getting array that backs this buffer
// using array() method
byte[] arr = (byte[])bb1.array();
// print the array
System.out.print("array is : [");
for (int i = 0; i < arr.length; i++)
System.out.print(" " + arr[i]);
System.out.print(" ]");
}
catch (ReadOnlyBufferException e) {
System.out.println("Exception throws: "
+ e);
}
}
}
Output:
array is : [ 20 30 40 50 ]
例 2:
// Java program to demonstrate
// array() method
import java.nio.*;
import java.util.*;
public class GFG {
public static void main(String[] args)
{
// Declaring the capacity of the ByteBuffer
int capacity = 4;
// Creating the ByteBuffer
try {
// creating object of ByteBuffer
// and allocating size capacity
ByteBuffer bb = ByteBuffer.allocate(capacity);
// putting the int to byte typecast
// value in ByteBuffer
bb.put((byte)20);
bb.put((byte)30);
bb.put((byte)40);
bb.put((byte)50);
// Creating a read-only copy of ByteBuffer
// using asReadOnlyBuffer() method
ByteBuffer bb1 = bb.asReadOnlyBuffer();
// Typecasting Read only ByteBuffer
// into Read-only Buffer
Buffer buffer = (Buffer)bb1;
// getting array that backs this buffer
// using array() method
byte[] arr = (byte[])buffer.array();
// print the array
System.out.print("array is : [");
for (int i = 0; i < arr.length; i++)
System.out.print(" " + arr[i]);
System.out.print(" ]");
}
catch (ReadOnlyBufferException e) {
System.out.println("buffer is backed by "
+ "an array but is read-only");
System.out.println("Exception throws: " + e);
}
}
}
Output:
buffer is backed by an array but is read-only
Exception throws: java.nio.ReadOnlyBufferException
参考:https://docs . Oracle . com/javase/9/docs/API/Java/nio/buffer . html # array–
版权属于：月萌API www.moonapi.com，转载请注明出处
