Java中的 LongBuffer allocate() 方法

Java.nio.LongBuffer 类的allocate()方法用于在现有缓冲区旁边分配一个新的Long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 LongBuffer allocate(Long capacity)

参数：此方法将新缓冲区的容量（Long）作为参数。
返回值：此方法返回新的 Long 缓冲区。
异常：如果容量为负 Longer，此方法将引发IllegalArgumentException 。
下面的程序说明了 allocate() 方法：
方案一：

Java

// 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 LongBuffer
        int Capacity = 10;
 
        // Creating the LongBuffer
 
        // creating object of Longbuffer
        // and allocating size capacity
        LongBuffer ib = LongBuffer.allocate(Capacity);
 
        // putting the value in Longbuffer
        ib.put(11);
        ib.put(2, 19);
 
        System.out.println("LongBuffer: "
                           + Arrays.toString(ib.array()));
    }
}

输出：

LongBuffer: [11, 0, 19, 0, 0, 0, 0, 0, 0, 0]

程序2：演示IllegalArgumentException

Java

// 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 LongBuffer
        // by negative Longer
        int Capacity = -10;
 
        // Creating the LongBuffer
        try {
 
            // creating object of Longbuffer
            // and allocating size with negative Longer
            System.out.println("Trying to allocate a Negative Longer");
 
            LongBuffer ib = LongBuffer.allocate(Capacity);
        }
        catch (IllegalArgumentException e) {
            System.out.println("Exception thrown: " + e);
        }
    }
}

输出

Trying to allocate a Negative Longer
Exception thrown: java.lang.IllegalArgumentException: capacity < 0: (-10 < 0)