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Java ByteBuffer getInt()用法及代码示例


getInt()

java.nio.ByteBuffer类的getInt()方法用于读取此缓冲区当前位置的下四个字节，并根据当前字节顺序将它们组成一个int值，然后将该位置加4。

用法:

public abstract int getInt()

返回值：此方法返回缓冲区当前位置的int值


抛出：此方法引发BufferUnderflowException-如果此缓冲区中剩余的字节数少于四个。
下面是说明getInt()方法的示例：

范例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); 
        } 
    } 
}
输出： 
Original ByteBuffer: 
10 20 30 

Byte Value: 10
Next Byte Value: 20

范例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); 
        } 
    } 
}
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： https://docs.oracle.com/javase/9/docs/api/java/nio/ByteBuffer.html#getInt–

getInt(int索引)

ByteBuffer的getInt(int index)方法用于读取给定索引处的四个字节，并根据当前字节顺序将它们组成一个int值。

用法:

public abstract int getInt(int index)

参数：此方法将索引(将从中读取Byte的索引)作为参数。

返回值：此方法返回给定索引处的int值。


异常：此方法引发IndexOutOfBoundsException。如果index为负或不小于缓冲区的限制，则抛出此异常。

以下示例说明了getInt(int index)方法：

范例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); 
        } 
    } 
}
输出： 
Original ByteBuffer: 
10 20 

Byte Value: 10
Next Byte Value: 20

范例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); 
        } 
    } 
}
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： https://docs.oracle.com/javase/9/docs/api/java/nio/ByteBuffer.html#getInt-int-



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注：本文由纯净天空筛选整理自RohitPrasad3大神的英文原创作品 ByteBuffer getInt() method in Java with Examples。非经特殊声明，原始代码版权归原作者所有，本译文未经允许或授权，请勿转载或复制。