极客教程Java ByteBuffer getFloat()方法的例子
java.nio.ByteBuffer 类的 getFloat() 方法用于读取该缓冲区当前位置的下四个字节，根据当前的字节顺序将其合成为一个浮点数，然后将该位置递增四个。
语法
public abstract float getFloat()
返回值： 该方法返回缓冲区当前位置的浮点数。
异常： 如果该缓冲区内剩余的字节数少于4个，该方法会抛出 BufferUnderflowException 。
下面是说明getFloat()方法的例子。
例子 1 :
// Java program to demonstrate
// getFloat() method
import java.nio.*;
import java.util.*;
public class GFG {
public static void main(String[] args)
{
// Declaring the capacity of the ByteBuffer
int capacity = 8;
// Creating the ByteBuffer
try {
// creating object of ByteBuffer
// and allocating size capacity
ByteBuffer bb = ByteBuffer.allocate(capacity);
// putting the double value in the bytebuffer
bb.asFloatBuffer()
.put(12.3f)
.put(28.44f);
// rewind the Bytebuffer
bb.rewind();
// print the ByteBuffer
System.out.println("Original ByteBuffer: ");
for (int i = 1; i <= capacity / 4; i++)
System.out.print(bb.getFloat() + " ");
// rewind the Bytebuffer
bb.rewind();
// Reads the Float at this buffer's current position
// using getFloat() method
float value = bb.getFloat();
// print the float value
System.out.println("\n\nByte Value: " + value);
// Reads the float at this buffer's next position
// using getFloat() method
float value1 = bb.getFloat();
// print the float value
System.out.print("\nNext Byte Value: " + value1);
}
catch (BufferUnderflowException e) {
System.out.println("\nException Thrown : " + e);
}
}
}
输出。
Original ByteBuffer:
12.3 28.44
Byte Value: 12.3
Next Byte Value: 28.44
例子 2 :
// Java program to demonstrate
// getFloat() method
import java.nio.*;
import java.util.*;
public class GFG {
public static void main(String[] args)
{
// Declaring the capacity of the ByteBuffer
int capacity = 8;
// Creating the ByteBuffer
try {
// creating object of ByteBuffer
// and allocating size capacity
ByteBuffer bb = ByteBuffer.allocate(capacity);
// putting the double value in the bytebuffer
bb.asFloatBuffer()
.put(12.3f)
.put(28.44f);
// rewind the Bytebuffer
bb.rewind();
// print the ByteBuffer
System.out.println("Original ByteBuffer: ");
for (int i = 1; i <= capacity / 4; i++)
System.out.print(bb.getFloat() + " ");
// rewind the Bytebuffer
bb.rewind();
// Reads the Float at this buffer's current position
// using getFloat() method
float value = bb.getFloat();
// print the float value
System.out.println("\n\nByte Value: " + value);
// Reads the float at this buffer's next position
// using getFloat() method
float value1 = bb.getFloat();
// print the float value
System.out.println("\nNext Byte Value: " + value1);
// Reads the float at this buffer's next position
// using getFloat() method
float value2 = bb.getFloat();
}
catch (BufferUnderflowException e) {
System.out.println("\nthere are fewer "
+ "than eight bytes remaining"
+ " in this buffer");
System.out.println("Exception Thrown : " + e);
}
}
}
输出。
Original ByteBuffer:
12.3 28.44
Byte Value: 12.3
Next Byte Value: 28.44
there are fewer than eight bytes remaining in this buffer
Exception Thrown : java.nio.BufferUnderflowException
参考资料：https://docs.oracle.com/javase/9/docs/api/java/nio/ByteBuffer.html#getFloat-
getFloat(int index)
java.nio.ByteBuffer 的 getFloat(int index) 方法用于在给定的索引处读取四个字节，根据当前的字节顺序将它们合成为一个浮点数。
语法
public abstract float getFloat(int index)
参数： 该方法以index为参数，它是将被读取的字节的索引。
返回值 ：该方法返回给定索引处的浮点数。
异常： 如果索引为负数或不小于缓冲区的限制，该方法会抛出 IndexOutOfBoundsException 。
下面是说明getFloat(int index)方法的例子。
例子 1 :
// Java program to demonstrate
// getFloat() method
import java.nio.*;
import java.util.*;
public class GFG {
public static void main(String[] args)
{
// Declaring the capacity of the ByteBuffer
int capacity = 8;
// Creating the ByteBuffer
try {
// creating object of ByteBuffer
// and allocating size capacity
ByteBuffer bb = ByteBuffer.allocate(capacity);
// putting the double value in the bytebuffer
bb.asFloatBuffer()
.put(12.3f)
.put(28.44f);
// rewind the Bytebuffer
bb.rewind();
// print the ByteBuffer
System.out.println("Original ByteBuffer: ");
for (int i = 1; i <= capacity / 4; i++)
System.out.print(bb.getFloat() + " ");
// rewind the Bytebuffer
bb.rewind();
// Reads the Float at this buffer's current position
// using getFloat() method
float value = bb.getFloat(0);
// print the float value
System.out.println("\n\nByte Value: " + value);
// Reads the float at this buffer's next position
// using getFloat() method
float value1 = bb.getFloat(4);
// print the float value
System.out.println("\nNext Byte Value: " + value1);
}
catch (IndexOutOfBoundsException e) {
System.out.println("\nindex is negative or smaller"
+ " than the buffer's limit, "
+ "minus seven");
System.out.println("Exception Thrown : " + e);
}
}
}
输出。
Original ByteBuffer:
12.3 28.44
Byte Value: 12.3
Next Byte Value: 28.44
例子 2 :
// Java program to demonstrate
// getFloat() method
import java.nio.*;
import java.util.*;
public class GFG {
public static void main(String[] args)
{
// Declaring the capacity of the ByteBuffer
int capacity = 8;
// Creating the ByteBuffer
try {
// creating object of ByteBuffer
// and allocating size capacity
ByteBuffer bb = ByteBuffer.allocate(capacity);
// putting the double value in the bytebuffer
bb.asFloatBuffer()
.put(12.3f)
.put(28.44f);
// rewind the Bytebuffer
bb.rewind();
// print the ByteBuffer
System.out.println("Original ByteBuffer: ");
for (int i = 1; i <= capacity / 4; i++)
System.out.print(bb.getFloat() + " ");
// rewind the Bytebuffer
bb.rewind();
// Reads the Float at this buffer's current position
// using getFloat() method
float value = bb.getFloat(0);
// print the float value
System.out.println("\n\nByte Value: " + value);
// Reads the float at this buffer's next position
// using getFloat() method
float value1 = bb.getFloat(6);
// print the float value
System.out.println("\nNext Byte Value: " + value1);
}
catch (IndexOutOfBoundsException e) {
System.out.println("\nindex is negative or"
+ " smaller than the buffer's "
+ "limit, minus seven");
System.out.println("Exception Thrown : " + e);
}
}
}
输出。
Original ByteBuffer:
12.3 28.44
Byte Value: 12.3
index is negative or smaller than the buffer's limit, minus seven
Exception Thrown : java.lang.IndexOutOfBoundsException
参考资料: https://docs.oracle.com/javase/9/docs/api/java/nio/ByteBuffer.html#getFloat-int-