极客教程Java ByteBuffer put()方法与实例
put(byte b)
java.nio.ByteBuffer 类的 put(byte b) 方法用于将给定的字节写入新创建的字节缓冲区的当前位置，然后递增该位置。
语法:
public abstract ByteBuffer put(byte f)
参数： 该方法以字节值 b 为参数，将其写入字节缓冲区中。
返回值： 该方法返回这个缓冲区，其中插入了字节值。
异常： 该方法会抛出以下异常。
- BufferOverflowException- 如果这个缓冲区的当前位置不小于它的极限值。
- ReadOnlyBufferException- 如果这个缓冲区是只读的。
下面是说明put(byte b)方法的例子。
例1 :
// Java program to demonstrate
// put() method
import java.nio.*;
import java.util.*;
public class GFG {
public static void main(String[] args)
{
// Declaring the capacity of the ByteBuffer
int capacity = 3;
// Creating the ByteBuffer
try {
// creating object of ByteBuffer
// and allocating size capacity
ByteBuffer bb = ByteBuffer.allocate(capacity);
// putting the value in ByteBuffer using put() method
bb.put((byte)10)
.put((byte)20)
.put((byte)30)
.rewind();
// print the ByteBuffer
System.out.println("Original ByteBuffer: "
+ Arrays.toString(bb.array()));
}
catch (BufferOverflowException e) {
System.out.println("Exception throws : " + e);
}
catch (ReadOnlyBufferException e) {
System.out.println("Exception throws : " + e);
}
}
}
输出
Original ByteBuffer: [10, 20, 30]
例2： 为了证明BufferOverflowException。
// Java program to demonstrate
// put() method
import java.nio.*;
import java.util.*;
public class GFG {
public static void main(String[] args)
{
// Declaring the capacity of the ByteBuffer
int capacity = 3;
// Creating the ByteBuffer
try {
// creating object of ByteBuffer
// and allocating size capacity
ByteBuffer bb = ByteBuffer.allocate(capacity);
// putting the value in ByteBuffer using put() method
bb.put((byte)10)
.put((byte)20)
.put((byte)30);
// print the ByteBuffer
System.out.println("Original ByteBuffer: "
+ Arrays.toString(bb.array()));
// again putting the value in ByteBuffer
// using put() method
System.out.println("\nBuffer position : "
+ bb.position());
bb.put((byte)40);
}
catch (BufferOverflowException e) {
System.out.println("buffer's current position "
+ "is not smaller than its limit");
System.out.println("Exception throws : " + e);
}
catch (ReadOnlyBufferException e) {
System.out.println("Exception throws : " + e);
}
}
}
输出
Original ByteBuffer: [10, 20, 30]
Buffer position : 3
buffer's current position is not smaller than its limit
Exception throws : java.nio.BufferOverflowException
实例3： 为了证明ReadOnlyBufferException。
// Java program to demonstrate
// put() method
import java.nio.*;
import java.util.*;
public class GFG {
public static void main(String[] args)
{
// Declaring the capacity of the ByteBuffer
int capacity = 3;
// Creating the ByteBuffer
try {
// creating object of ByteBuffer
// and allocating size capacity
ByteBuffer bb = ByteBuffer.allocate(capacity);
// putting the value in ByteBuffer using put() method
bb.put((byte)10)
.put((byte)20)
.put((byte)30);
// print the ByteBuffer
System.out.println("Original ByteBuffer: "
+ Arrays.toString(bb.array()));
// Creating a read-only copy of ByteBuffer
// using asReadOnlyBuffer() method
ByteBuffer bb1 = bb.asReadOnlyBuffer();
System.out.println("\nTrying to put the byte value"
+ " in read only buffer");
// putting the value in readonly ByteBuffer
// using put() method
bb1.put((byte)40);
}
catch (BufferOverflowException e) {
System.out.println("buffer's current position "
+ "is not smaller than its limit");
System.out.println("Exception throws : " + e);
}
catch (ReadOnlyBufferException e) {
System.out.println("Exception throws : " + e);
}
}
}
输出
Original ByteBuffer: [10, 20, 30]
Trying to put the byte value in read only buffer
Exception throws : java.nio.ReadOnlyBufferException
参考资料 ：https://docs.oracle.com/javase/9/docs/api/java/nio/ByteBuffer.html#put-byte-
put(int index, byte f)
java.nio.ByteBuffer类 的 put(int index, byte f) 方法是用来将给定的字节写入给定索引的缓冲区中。
语法
public abstract ByteBuffer put(int index, byte f)
参数： 该方法接受以下参数作为参数。
- index : 将被写入的字节的索引
- f : 要写入的字节值
返回值 ：该方法返回这个缓冲区。
异常： 该方法会抛出以下异常。
- IndexOutOfBoundsException- 如果索引是负数或者不小于缓冲区的极限值。
- ReadOnlyBufferException- 如果这个缓冲区是只读的。
下面是一些例子来说明put(int index, byte f)方法。
例子1 :
// Java program to demonstrate
// put() method
import java.nio.*;
import java.util.*;
public class GFG {
public static void main(String[] args)
{
// Declaring the capacity of the ByteBuffer
int capacity = 3;
// Creating the ByteBuffer
try {
// creating object of ByteBuffer
// and allocating size capacity
ByteBuffer bb = ByteBuffer.allocate(capacity);
// putting the value in ByteBuffer using put() at index 0
bb.put(0, (byte)10);
// putting the value in ByteBuffer using put() at index 2
bb.put(2, (byte)20);
// putting the value in ByteBuffer using put() at index 1
bb.put(1, (byte)30);
// rewinding the ByteBuffer
bb.rewind();
// print the ByteBuffer
System.out.println("Original ByteBuffer: "
+ Arrays.toString(bb.array()));
}
catch (IndexOutOfBoundsException e) {
System.out.println("Exception throws : " + e);
}
catch (ReadOnlyBufferException e) {
System.out.println("Exception throws : " + e);
}
}
}
输出
Original ByteBuffer: [10, 30, 20]
例2： 演示IndexOutOfBoundsException。
// Java program to demonstrate
// put() method
import java.nio.*;
import java.util.*;
public class GFG {
public static void main(String[] args)
{
// Declaring the capacity of the ByteBuffer
int capacity = 3;
// Creating the ByteBuffer
try {
// creating object of ByteBuffer
// and allocating size capacity
ByteBuffer bb = ByteBuffer.allocate(capacity);
// putting the value in ByteBuffer using put() at index 0
bb.put(0, (byte)10);
// putting the value in ByteBuffer using put() at index 2
bb.put(2, (byte)20);
// putting the value in ByteBuffer using put() at index 1
bb.put(1, (byte)30);
// rewinding the ByteBuffer
bb.rewind();
// print the ByteBuffer
System.out.println("Original ByteBuffer: "
+ Arrays.toString(bb.array()));
// putting the value in ByteBuffer using put() at index -1
bb.put(-1, (byte)40);
}
catch (IndexOutOfBoundsException e) {
System.out.println("\nindex is negative or not smaller "
+ "than the buffer's limit");
System.out.println("Exception throws : " + e);
}
catch (ReadOnlyBufferException e) {
System.out.println("Exception throws : " + e);
}
}
}
输出
Original ByteBuffer: [10, 30, 20]
index is negative or not smaller than the buffer's limit
Exception throws : java.lang.IndexOutOfBoundsException
例3： 演示ReadOnlyBufferException。
// Java program to demonstrate
// put() method
import java.nio.*;
import java.util.*;
public class GFG {
public static void main(String[] args)
{
// Declaring the capacity of the ByteBuffer
int capacity = 3;
// Creating the ByteBuffer
try {
// creating object of ByteBuffer
// and allocating size capacity using allocate() method
ByteBuffer bb = ByteBuffer.allocate(capacity);
// Creating a read-only copy of ByteBuffer
// using asReadOnlyBuffer() method
ByteBuffer bb1 = bb.asReadOnlyBuffer();
System.out.println("Trying to put the byte value"
+ " in read only buffer");
// putting the value in readonly ByteBuffer
// using put() method
bb1.put(0, (byte)10);
}
catch (IndexOutOfBoundsException e) {
System.out.println("Exception throws : " + e);
}
catch (ReadOnlyBufferException e) {
System.out.println("Exception throws : " + e);
}
}
}
输出
Trying to put the byte value in read only buffer
Exception throws : java.nio.ReadOnlyBufferException
参考资料: https://docs.oracle.com/javase/9/docs/api/java/nio/ByteBuffer.html#put-int-byte-