Java DoubleBuffer get()方法及实例

java.nio.DoubleBuffer类的 get() 方法用于读取指定缓冲区当前位置的双倍数，然后递增该位置。

语法

public abstract double get()

返回值： 该方法返回缓冲区当前位置的双倍值。

异常： 该方法抛出 BufferUnderflowException ，如果缓冲区的当前位置不小于其极限值，则抛出此异常。

下面是说明get()方法的例子。

例子 1 :

// Java program to demonstrate
// get() method
  
import java.nio.*;
import java.util.*;
  
public class GFG {
  
    public static void main(String[] args)
    {
  
        // Declaring the capacity of the FloatBuffer
        int capacity = 5;
  
        // Creating the FloatBuffer
        try {
  
            // creating object of floatbuffer
            // and allocating size capacity
            DoubleBuffer fb
                = DoubleBuffer.allocate(capacity);
  
            // putting the value in Doublebuffer
            fb.put(8.56D);
            fb.put(9.61D);
            fb.put(1.24D);
            fb.rewind();
  
            // print the DoubleBuffer
            System.out.println("Original DoubleBuffer:  "
                               + Arrays.toString(fb.array()));
  
            // Reads the double at this buffer's current position
            // using get() method
            double value = fb.get();
  
            // print the double value
            System.out.println("\nDouble Value: "
                               + value);
  
            // Reads the  double at this buffer's next position
            // using get() method
            double value1 = fb.get();
  
            // print the double value
            System.out.print("\nNext double Value: " + value1);
        }
  
        catch (IllegalArgumentException e) {
  
            System.out.println("\nIllegalArgumentException catched");
        }
  
        catch (ReadOnlyBufferException e) {
  
            System.out.println("\nReadOnlyBufferException catched");
        }
  
        catch (BufferUnderflowException e) {
  
            System.out.println("\nException throws: " + e);
        }
    }
}

输出:

Original DoubleBuffer:  [8.56, 9.61, 1.24, 0.0, 0.0]

Double Value: 8.56

Next double Value: 9.61

例子 2 :

// Java program to demonstrate
// get() method
  
import java.nio.*;
import java.util.*;
  
public class GFG {
  
    public static void main(String[] args)
    {
  
        // Declaring the capacity of the DoubleBuffer
        int capacity = 3;
  
        // Creating the DoubleBuffer
        try {
  
            // creating object of Doublebuffer
            // and allocating size capacity
            DoubleBuffer fb = DoubleBuffer.allocate(capacity);
  
            // putting the value in Doublebuffer
            fb.put(8.56F);
            fb.put(9.61F);
  
            // print the DoubleBuffer
            System.out.println("Original DoubleBuffer:  "
                               + Arrays.toString(fb.array()));
  
            // Reads the Double at this buffer's current position
            // using get() method
            Double value = fb.get();
  
            // print the Double value
            System.out.println("\nDouble Value: " + value);
  
            // Reads the  Double at this buffer's next position
            // using get() method
            System.out.print("\nsince the buffer current"
                             + " position is incremented");
            System.out.print(" to greater than its limit ");
  
            Double value1 = fb.get();
  
            // print the Double value
            System.out.print("\nNext Double Value: " + value1);
        }
  
        catch (IllegalArgumentException e) {
  
            System.out.println("\nIllegalArgumentException catched");
        }
  
        catch (ReadOnlyBufferException e) {
  
            System.out.println("\nReadOnlyBufferException catched");
        }
  
        catch (BufferUnderflowException e) {
  
            System.out.println("\nException throws: " + e);
        }
    }
}

输出:

Original DoubleBuffer:  [8.5600004196167, 9.609999656677246, 0.0]

Double Value: 0.0

since the buffer current position is incremented to greater than its limit 
Exception throws: java.nio.BufferUnderflowException

参考资料: https://docs.oracle.com/javase/9/docs/api/java/nio/DoubleBuffer.html#get-