Java 中的 FloatBuffer rewind()方法，示例
原文:https://www . geeksforgeeks . org/float buffer-rewind-methods-in-Java-with-examples/
java.nio.FloatBuffer 类的倒带()方法用来倒带这个缓冲区。此方法将位置设置为零，限制保持不变，如果有任何先前标记的位置，将被丢弃。当需要进行通道写或获取操作时，应调用此方法。这意味着，如果缓冲区数据已经写入，则需要将其复制到另一个数组中。例如:
out.write(buf); // Writes the remaining data
buf.rewind(); // Rewind the buffer
buf.get(array); // Copy data into array
语法:
public final FloatBuffer rewind()
参数:该方法不取任何参数。
返回值:该方法返回该缓冲区。
以下是说明 rewind()方法的示例:
示例 1:
// Java program to demonstrate
// rewind() method
import java.nio.*;
import java.util.*;
public class GFG {
public static void main(String[] args)
{
// defining and allocating FloatBuffer
// using allocate() method
FloatBuffer floatBuffer = FloatBuffer.allocate(4);
// put char value in FloatBuffer
// using put() method
floatBuffer.put(10.5f);
floatBuffer.put(20.5f);
// print the float buffer
System.out.println("Buffer before operation: "
+ Arrays.toString(
floatBuffer.array())
+ "\nPosition: "
+ floatBuffer.position()
+ "\nLimit: "
+ floatBuffer.limit());
// rewind the Buffer
// using rewind() method
floatBuffer.rewind();
// print the floatbuffer
System.out.println("\nBuffer after operation: "
+ Arrays.toString(
floatBuffer.array())
+ "\nPosition: "
+ floatBuffer.position()
+ "\nLimit: "
+ floatBuffer.limit());
}
}
输出:
Buffer before operation: [10.5, 20.5, 0.0, 0.0]
Position: 2
Limit: 4
Buffer after operation: [10.5, 20.5, 0.0, 0.0]
Position: 0
Limit: 4
示例 2:
// Java program to demonstrate
// rewind() method
import java.nio.*;
import java.util.*;
public class GFG {
public static void main(String[] args)
{
// defining and allocating FloatBuffer
// using allocate() method
FloatBuffer floatBuffer
= FloatBuffer.allocate(5);
// put float value in floatBuffer
// using put() method
floatBuffer.put(10.5f);
floatBuffer.put(20.5f);
floatBuffer.put(30.5f);
// mark will be going to discarded by rewind()
floatBuffer.mark();
// print the buffer
System.out.println("Buffer before operation: "
+ Arrays.toString(
floatBuffer.array())
+ "\nPosition: "
+ floatBuffer.position()
+ "\nLimit: "
+ floatBuffer.limit());
// Rewind the Buffer
// using rewind() method
floatBuffer.rewind();
// print the buffer
System.out.println("\nBuffer after operation: "
+ Arrays.toString(
floatBuffer.array())
+ "\nPosition: "
+ floatBuffer.position()
+ "\nLimit: "
+ floatBuffer.limit());
}
}
输出:
Buffer before operation: [10.5, 20.5, 30.5, 0.0, 0.0]
Position: 3
Limit: 5
Buffer after operation: [10.5, 20.5, 30.5, 0.0, 0.0]
Position: 0
Limit: 5
参考:https://docs . Oracle . com/javase/9/docs/API/Java/nio/float buffer . html # rewind–
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