Guava Chars.toArray() 方法与实例

Guava库中Chars类的toArray()方法用于将作为参数传递给该方法的char值转换成Char数组。这些char值被作为一个集合传递给这个方法。该方法返回一个Char数组.

语法:

public static char[] toArray(Collection collection)

参数: 这个方法接受一个强制参数collection，它是要转换为char数组的char值的集合。

返回值: 该方法返回一个char数组，包含与collection相同的值，顺序相同。

异常情况: 如果传递的集合或其任何元素为空，该方法会抛出NullPointerException。

以下程序说明了toArray()方法的使用。

例子 1 :

// Java code to show implementation of
// Guava's Chars.toArray() method
  
import com.google.common.primitives.Chars;
import java.util.Arrays;
import java.util.List;
  
class GFG {
  
    // Driver's code
    public static void main(String[] args)
    {
  
        // Creating a List of Chars
        List<Character> myList
            = Arrays.asList('G', 'E', 'E', 'K', 'S');
  
        // Using Chars.toArray() method to convert
        // a List or Set of Char to an array of Char
        char[] arr = Chars.toArray(myList);
  
        // Displaying an array containing each
        // value of collection,
        // converted to a char value
        System.out.println(Arrays.toString(arr));
    }
}

输出:

[G, E, E, K, S]

例子 2 :

// Java code to show implementation of
// Guava's Chars.toArray() method
  
import com.google.common.primitives.Chars;
import java.util.Arrays;
import java.util.List;
  
class GFG {
  
    // Driver's code
    public static void main(String[] args)
    {
  
        try {
            // Creating a List of Chars
            List<Character> myList
                = Arrays.asList('a', 'b', null);
  
            // Using Chars.toArray() method
            // to convert a List or Set of Char
            // to an array of Char.
            // This should raise "NullPointerException"
            // as the collection contains "null"
            // as an element
            char[] arr = Chars.toArray(myList);
  
            // Displaying an array containing each
            // value of collection,
            // converted to a char value
            System.out.println(Arrays
                                   .toString(arr));
        }
        catch (Exception e) {
            System.out.println(e);
        }
    }
}

输出: