极客教程Java ByteBuffer getInt()方法的例子
getInt( )
java.nio.ByteBuffer 类的 getInt() 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int值，然后将该位置递增四个。
语法
public abstract int getInt()
返回值： 该方法返回缓冲区当前位置的int值。
抛出： 该方法抛出 BufferUnderflowException - 如果该缓冲区内剩余的字节数少于四个。
下面是说明getInt()方法的例子。
例子 1 :
// Java program to demonstrate
// getInt() method
import java.nio.*;
import java.util.*;
public class GFG {
public static void main(String[] args)
{
// Declaring the capacity of the ByteBuffer
int capacity = 12;
// Creating the ByteBuffer
try {
// creating object of ByteBuffer
// and allocating size capacity
ByteBuffer bb = ByteBuffer.allocate(capacity);
// putting the int value in the bytebuffer
bb.asIntBuffer()
.put(10)
.put(20)
.put(30);
// 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.getInt() + " ");
// rewind the Bytebuffer
bb.rewind();
// Reads the Int at this buffer's current position
// using getInt() method
int value = bb.getInt();
// print the int value
System.out.println("\n\nByte Value: " + value);
// Reads the int at this buffer's next position
// using getInt() method
int value1 = bb.getInt();
// print the int value
System.out.println("Next Byte Value: " + value1);
}
catch (BufferUnderflowException e) {
System.out.println("\nException Thrown : " + e);
}
}
}
输出。
Original ByteBuffer:
10 20 30
Byte Value: 10
Next Byte Value: 20
例子 2 :
// Java program to demonstrate
// getInt() 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 int value in the bytebuffer
bb.asIntBuffer()
.put(10)
.put(20);
// 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.getInt() + " ");
// rewind the Bytebuffer
bb.rewind();
// Reads the Int at this buffer's current position
// using getInt() method
int value = bb.getInt();
// print the int value
System.out.println("\n\nByte Value: " + value);
// Reads the int at this buffer's next position
// using getInt() method
int value1 = bb.getInt();
// print the int value
System.out.println("Next Byte Value: " + value1);
// Reads the int at this buffer's next position
// using getInt() method
int value2 = bb.getInt();
}
catch (BufferUnderflowException e) {
System.out.println("\nthere are fewer than "
+ "four bytes remaining in this buffer");
System.out.println("Exception Thrown : " + e);
}
}
}
输出。
Original ByteBuffer:
10 20
Byte Value: 10
Next Byte Value: 20
there are fewer than four 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#getInt-
getInt(int index)
ByteBuffer 的 getInt(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int值。
语法:
public abstract int getInt(int index)
参数： 该方法以index（将被读取的字节的索引）为参数。
返回值： 该方法返回给定索引处的int值。
异常： 该方法抛出 IndexOutOfBoundsException。 如果索引为负数或不小于缓冲区的限制，就会抛出这个异常。
下面是说明getInt(int index)方法的例子。
例子 1 :
// Java program to demonstrate
// getInt() 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 int value in the bytebuffer
bb.asIntBuffer()
.put(10)
.put(20);
// 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.getInt() + " ");
// rewind the Bytebuffer
bb.rewind();
// Reads the Int at this buffer's current position
// using getInt() method
int value = bb.getInt(0);
// print the int value
System.out.println("\n\nByte Value: " + value);
// Reads the int at this buffer's next position
// using getInt() method
int value1 = bb.getInt(4);
// print the int value
System.out.println("Next 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:
10 20
Byte Value: 10
Next Byte Value: 20
例子 2 :
// Java program to demonstrate
// getInt() 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 int value in the bytebuffer
bb.asIntBuffer()
.put(10)
.put(20);
// 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.getInt() + " ");
// rewind the Bytebuffer
bb.rewind();
// Reads the Int at this buffer's current position
// using getInt() method
int value = bb.getInt(0);
// print the int value
System.out.println("\n\nByte Value: " + value);
// Reads the int at this buffer's next position
// using getInt() method
int value1 = bb.getInt(7);
// print the int value
System.out.println("Next 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:
10 20
Byte Value: 10
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#getInt-int-