Java中的 IntBuffer allocate() 方法

Java.nio.IntBuffer 类的allocate()方法用于在现有缓冲区旁边分配一个新的int缓冲区。新缓冲区的位置将为零。它的极限将是它的容量。它的标记将是未定义的。并且它的每个元素都将被初始化为零。它将有一个支持数组，并且它的数组偏移量为零。

句法：

public static IntBuffer allocate(int capacity)

参数：此方法将新缓冲区的容量（以 int 为单位）作为参数。

返回值：此方法返回新的 int 缓冲区。

异常：如果容量为负整数，此方法将引发IllegalArgumentException 。

下面的程序说明了 allocate() 方法：

示例 1：

// Java program to demonstrate
// allocate() method
  
import java.nio.*;
import java.util.*;
  
public class GFG {
    public static void main(String[] args)
    {
  
        // Declaring the capacity of the IntBuffer
        int Capacity = 10;
  
        // Creating the IntBuffer
  
        // creating object of intbuffer
        // and allocating size capacity
        IntBuffer ib = IntBuffer.allocate(Capacity);
  
        // putting the value in intbuffer
        ib.put(11);
        ib.put(2, 19);
  
        System.out.println("IntBuffer: "
                           + Arrays.toString(ib.array()));
    }
}

输出：

IntBuffer: [11, 0, 19, 0, 0, 0, 0, 0, 0, 0]

示例 2：演示 IllegalArgumentException

// Java program to demonstrate
// allocate() method
  
import java.nio.*;
import java.util.*;
  
public class GFG {
    public static void main(String[] args)
    {
  
        // Declaring the capacity of the IntBuffer
        // by negative integer
        int Capacity = -10;
  
        // Creating the IntBuffer
        try {
  
            // creating object of intbuffer
            // and allocating size with negative integer
            System.out.println("Trying to allocate a Negative Integer");
  
            IntBuffer ib = IntBuffer.allocate(Capacity);
        }
        catch (IllegalArgumentException e) {
            System.out.println("Exception thrown: " + e);
        }
    }
}

输出：

Trying to allocate a Negative Integer
Exception thrown: java.lang.IllegalArgumentException