Java 中的 ByteBuffer getInt()方法，带示例
原文:https://www . geeksforgeeks . org/bytebuffer-getint-method-in-Java-with-examples/
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，根据当前字节顺序将其组成一个 Int 值，然后将该位置递增四。
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:这个方法抛出bufferenderflow exception–如果这个缓冲区剩余的字节少于 4 个。 下面是说明 getInt()方法的例子:
实施例 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);
}
}
}
Output:
Original ByteBuffer:
10 20 30
Byte Value: 10
Next Byte Value: 20
实施例 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);
}
}
}
Output:
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:https://docs . Oracle . com/javase/9/docs/API/Java/nio/bytebuffer . html # getInt–
getInt(int index)
字节缓冲的 getInt(Int index) 方法用于读取给定索引处的四个字节，根据当前字节顺序将它们组成一个 int 值。
语法:
public abstract int getInt(int index)
参数:该方法以索引(将从中读取字节的索引)为参数。
返回值:该方法返回给定索引处的 int 值。
异常:此方法抛出indexout of boundsexception。如果索引为负或不小于缓冲区的限制，则会引发此异常。
以下是说明 getInt(int index) 方法的示例:
实施例 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);
}
}
}
Output:
Original ByteBuffer:
10 20
Byte Value: 10
Next Byte Value: 20
实施例 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);
}
}
}
Output:
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:https://docs . Oracle . com/javase/9/docs/API/Java/nio/bytebuffer . html # getInt-int-
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