用示例缓冲 Java 中的 isReadOnly()方法
原文:https://www . geesforgeks . org/buffer-is readonly-methods-in-Java-with-examples/
java.nio.Buffer 类的 isReadOnly() 方法用来判断这个缓冲区是否是只读的。
语法:
public abstract boolean isReadOnly()
返回:当且仅当该缓冲区为只读时，该方法将返回真。
以下是说明 isReadOnly() 方法的示例:
示例 1:
// Java program to demonstrate
// isReadOnly() method
import java.nio.*;
import java.util.*;
public class GFG {
public static void main(String[] args)
{
// Declaring the capacity of the ByteBuffer
int capacity = 10;
// creating object of bytebuffer
// and allocating size capacity
ByteBuffer bb = ByteBuffer.allocate(capacity);
// putting the value in bytebuffer
bb.put((byte)10);
bb.put((byte)20);
bb.rewind();
// Typecast bytebuffer to Buffer
Buffer buffer = (Buffer)bb;
// checking buffer is backed by array or not
boolean isReadOnly = buffer.isReadOnly();
// checking if else condition
if (isReadOnly)
System.out.println("buffer is"
+ " ReadOnly buffer");
else
System.out.println("buffer is not"
+ " ReadOnly buffer");
}
}
输出:
buffer is not ReadOnly buffer
示例 2:
// Java program to demonstrate
// isReadOnly() method
import java.nio.*;
import java.util.*;
public class GFG {
public static void main(String[] args)
{
// Declaring the capacity of the ByteBuffer
int capacity = 10;
// creating object of bytebuffer
// and allocating size capacity
ByteBuffer bb = ByteBuffer.allocate(capacity);
// putting the value in bytebuffer
bb.put((byte)10);
bb.put((byte)20);
bb.rewind();
// Creating a read-only copy of ByteBuffer
// using asReadOnlyBuffer() method
ByteBuffer bb1 = bb.asReadOnlyBuffer();
// Typecast read-only ByteBuffer to read-only buffer
Buffer buffer = (Buffer)bb1;
// checking buffer is backed by array or not
boolean isReadOnly = buffer.isReadOnly();
// checking if else condition
if (isReadOnly)
System.out.println("buffer is"
+ " ReadOnly buffer");
else
System.out.println("buffer is not"
+ " ReadOnly buffer");
}
}
输出:
buffer is ReadOnly buffer
参考:https://docs . Oracle . com/javase/9/docs/API/Java/nio/buffer . html # isReadOnly–
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