Java FloatBuffer limit()方法及示例

java.nio.FloatBuffer类的 limit() 方法是用来修改这个FloatBuffer的极限。这个方法以要设置的极限为参数，并将其设置为这个Buffer的新极限。如果这个Buffer的标记已经被定义，并且大于新指定的极限，那么这个新的极限就不会被设置并被丢弃。

语法

public final FloatBuffer limit(int newLimit)

参数： 该方法需要一个整数类型的参数newLimit，指的是要设置为缓冲区的新极限。

返回值： 该方法在将指定的新极限设置为该缓冲区的新极限后返回该缓冲区。

下面的例子说明了limit()方法的作用。

例子 1 :

// Java program to demonstrate// limit() 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 float value in FloatBuffer        // using put() method        floatBuffer.put(20.5f);        floatBuffer.put(30.5f);          // print the float buffer        System.out.println(            "FloatBuffer before "            + "setting buffer's limit: "            + Arrays.toString(                  floatBuffer.array())            + "\nPosition: "            + floatBuffer.position()            + "\nLimit: "            + floatBuffer.limit());          // Limit the floatBuffer        // using limit() method        floatBuffer.limit(1);          // print the float buffer        System.out.println(            "\nFloatBuffer after "            + "setting buffer's limit: "            + Arrays.toString(                  floatBuffer.array())            + "\nPosition: "            + floatBuffer.position()            + "\nLimit: "            + floatBuffer.limit());    }}

输出。

设置缓冲区限制前的FloatBuffer：
[20.5, 30.5, 0.0, 0.0]
位置：2
限制：4

设置缓冲区限制后的FloatBuffer：
[20.5, 30.5, 0.0, 0.0]
位置。1
限制：1

例子2 :

// Java program to demonstrate// limit() 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(20.5f);        floatBuffer.put(30.5f);        floatBuffer.put(40.5f);          // mark will be going to        // discarded by limit()        floatBuffer.mark();          // print the float buffer        System.out.println(            "FloatBuffer before "            + "setting buffer's limit: "            + Arrays.toString(                  floatBuffer.array())            + "\nPosition: "            + floatBuffer.position()            + "\nLimit: "            + floatBuffer.limit());          // Limit the floatBuffer        // using limit() method        floatBuffer.limit(4);          // print the double buffer        System.out.println(            "\nFloatBuffer before "            + "setting buffer's limit: "            + Arrays.toString(                  floatBuffer.array())            + "\nPosition: "            + floatBuffer.position()            + "\nLimit: "            + floatBuffer.limit());    }}

输出。

FloatBuffer before setting buffer’s limit:[20.5, 30.5, 40.5, 0.0, 0.0]Position: 3Limit: 5FloatBuffer before setting buffer’s limit:[20.5, 30.5, 40.5, 0.0, 0.0]Position: 3Limit: 4

参考 ：https://docs.oracle.com/javase/9/docs/api/java/nio/FloatBuffer.html#limit-int-