Java CharBuffer limit()方法及示例

java.nio.CharBuffer类的 limit() 方法是用来设置这个缓冲区的极限。如果位置大于新的极限，那么它将被设置为新的极限。如果标记被定义并且大于新的限制，那么它将被丢弃。

语法

public CharBuffer limit(int newLimit)

返回值： 该方法返回这个缓冲区。

下面是说明limit()方法的例子。

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 CharBuffer
        // using allocate() method
        CharBuffer charBuffer = CharBuffer.allocate(4);
  
        // append char value in CharBuffer
        // using char() method
        charBuffer.append('a');
        charBuffer.append('b');
  
        // print the char buffer
        System.out.println("CharBuffer before "
                           + "setting buffer's limit: "
                           + Arrays.toString(
                                 charBuffer.array())
                           + "\nPosition: "
                           + charBuffer.position()
                           + "\nLimit: "
                           + charBuffer.limit());
  
        // Limit the CharBuffer
        // using limit() method
        charBuffer.limit(1);
  
        // print the char buffer
        System.out.println("CharBuffer before "
                           + "setting buffer's limit: "
                           + Arrays.toString(
                                 charBuffer.array())
                           + "\nPosition: "
                           + charBuffer.position()
                           + "\nLimit: "
                           + charBuffer.limit());
    }
}

输出:

CharBuffer before setting buffer's limit: [a, b,,  ]
Position: 2
Limit: 4

CharBuffer after setting buffer's limit: [a, b,,  ]
Position: 1
Limit: 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 CharBuffer
        // using allocate() method
        CharBuffer charBuffer
            = CharBuffer.allocate(5);
  
        // append char value in CharBuffer
        // using char() method
        charBuffer.append('a');
        charBuffer.append('b');
        charBuffer.append('c');
  
        // mark will be going to discarded by limit()
        charBuffer.mark();
  
        // print the char buffer
        System.out.println("CharBuffer before "
                           + "setting buffer's limit: "
                           + Arrays.toString(
                                 charBuffer.array())
                           + "\nPosition: "
                           + charBuffer.position()
                           + "\nLimit: "
                           + charBuffer.limit());
  
        // Limit the charBuffer
        // using limit() method
        charBuffer.limit(4);
  
        // print the char buffer
        System.out.println("CharBuffer before "
                           + "setting buffer's limit: "
                           + Arrays.toString(
                                 charBuffer.array())
                           + "\nPosition: "
                           + charBuffer.position()
                           + "\nLimit: "
                           + charBuffer.limit());
    }
}

输出:

CharBuffer before setting buffer's limit: [a, b, c,,  ]
Position: 3
Limit: 5

CharBuffer after setting buffer's limit: [a, b, c,,  ]
Position: 3
Limit: 4

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