java.nio.ByteBuffer類的getDouble()方法用於讀取此緩衝區當前位置的下八個字節,根據當前字節順序將它們組成一個雙精度值,然後將該位置加8。
用法:
public abstract double getDouble()
返回值:此方法返回緩衝區當前位置的double值
引發:如果緩衝區的當前位置不小於其限製,則此方法引發BufferUnderflowException,然後引發此異常。
下麵是說明getDouble()方法的示例:
範例1:
// Java program to demonstrate
// getDouble() method
import java.nio.*;
import java.util.*;
public class GFG {
public static void main(String[] args)
{
// Declaring the capacity of the ByteBuffer
int capacity = 16;
// 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.asDoubleBuffer()
.put(1234.3456)
.put(2884.4444);
// rewind the Bytebuffer
bb.rewind();
// print the ByteBuffer
System.out.println("Original ByteBuffer: ");
for (int i = 1; i <= capacity / 8; i++)
System.out.print(bb.getDouble() + " ");
// rewind the Bytebuffer
bb.rewind();
// Reads the double at this buffer's current position
// using getDouble() method
double value = bb.getDouble();
// print the char value
System.out.println("\n\nByte Value: " + value);
// Reads the char at this buffer's next position
// using getDouble() method
double value1 = bb.getDouble();
// print the char value
System.out.print("\nNext Byte Value: " + value1);
}
catch (BufferUnderflowException e) {
System.out.println("\nException Thrown : " + e);
}
}
}
Original ByteBuffer: 1234.3456 2884.4444 Byte Value: 1234.3456 Next Byte Value: 2884.4444
範例2:
// Java program to demonstrate
// getDouble() method
import java.nio.*;
import java.util.*;
public class GFG {
public static void main(String[] args)
{
// Declaring the capacity of the ByteBuffer
int capacity = 16;
// 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.asDoubleBuffer()
.put(1234.3456)
.put(2884.4444);
// rewind the Bytebuffer
bb.rewind();
// print the ByteBuffer
System.out.println("Original ByteBuffer: ");
for (int i = 1; i <= capacity / 8; i++)
System.out.print(bb.getDouble() + " ");
// rewind the Bytebuffer
bb.rewind();
// Reads the double at this buffer's current position
// using getDouble() method
double value = bb.getDouble();
// print the char value
System.out.println("\n\nByte Value: " + value);
// Reads the char at this buffer's next position
// using getDouble() method
double value1 = bb.getDouble();
// print the char value
System.out.println("\nNext Byte Value: " + value1);
// Reads the char at this buffer's next position
// using getDouble() method
double value2 = bb.getDouble();
}
catch (BufferUnderflowException e) {
System.out.println("\nthere are fewer than "
+ "eight bytes remaining in"
+ " this buffer");
System.out.println("Exception Thrown : " + e);
}
}
}
Original ByteBuffer: 1234.3456 2884.4444 Byte Value: 1234.3456 Next Byte Value: 2884.4444 there are fewer than eight bytes remaining in this buffer Exception Thrown : java.nio.BufferUnderflowException
參考: https://docs.oracle.com/javase/9/docs/api/java/nio/ByteBuffer.html#getDouble–
ByteBuffer的getDouble(int index)方法用於讀取給定索引處的八個字節,並根據當前字節順序將它們組成一個double值。
用法:
public abstract double getDouble(int index)
參數:此方法將index作為參數,即將從中讀取Byte的索引。
返回值:此方法返回給定索引處的Double值
異常:此方法引發IndexOutOfBoundsException。如果index為負或不小於緩衝區的限製,則拋出此異常。
以下示例說明了getDouble(int index)方法:
範例1:
// Java program to demonstrate
// getDouble() method
import java.nio.*;
import java.util.*;
public class GFG {
public static void main(String[] args)
{
// Declaring the capacity of the ByteBuffer
int capacity = 16;
// 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.asDoubleBuffer()
.put(1234.3456)
.put(2884.4444);
// rewind the Bytebuffer
bb.rewind();
// Declaring the variable
double c;
// print the ByteBuffer
System.out.println("Original ByteBuffer: ");
for (int i = 1; i <= capacity / 8; i++)
System.out.print(bb.getDouble() + " ");
// rewind the Bytebuffer
bb.rewind();
// Reads the double at this buffer's current position
// using getDouble() method
double value = bb.getDouble(0);
// print the char value
System.out.println("\n\nByte Value: " + value);
// Reads the char at this buffer's next position
// using getDouble() method
double value1 = bb.getDouble(8);
// print the char value
System.out.print("\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);
}
}
}
Original ByteBuffer: 1234.3456 2884.4444 Byte Value: 1234.3456 Next Byte Value: 2884.4444
範例2:
// Java program to demonstrate
// getDouble() method
import java.nio.*;
import java.util.*;
public class GFG {
public static void main(String[] args)
{
// Declaring the capacity of the ByteBuffer
int capacity = 16;
// 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.asDoubleBuffer()
.put(1234.3456)
.put(2884.4444);
// rewind the Bytebuffer
bb.rewind();
// Declaring the variable
double c;
// print the ByteBuffer
System.out.println("Original ByteBuffer: ");
for (int i = 1; i <= capacity / 8; i++)
System.out.print(bb.getDouble() + " ");
// rewind the Bytebuffer
bb.rewind();
// Reads the double at this buffer's current position
// using getDouble() method
double value = bb.getDouble(0);
// print the char value
System.out.println("\n\nByte Value: " + value);
// Reads the char at this buffer's next position
// using getDouble() method
double value1 = bb.getDouble(9);
// print the char value
System.out.print("\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);
}
}
}
Original ByteBuffer: 1234.3456 2884.4444 Byte Value: 1234.3456 index is negative or smaller than the buffer's limit, minus seven Exception Thrown : java.lang.IndexOutOfBoundsException
參考: https://docs.oracle.com/javase/9/docs/api/java/nio/ByteBuffer.html#getDouble-int-
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注:本文由純淨天空篩選整理自RohitPrasad3大神的英文原創作品 ByteBuffer getDouble() method in Java with Examples。非經特殊聲明,原始代碼版權歸原作者所有,本譯文未經允許或授權,請勿轉載或複製。