Java中toCharArray()方法

Java中 toCharArray() 方法詳解

《Thinking in Java》Chapter11中存在下列代碼

package holding;
import java.util.*;
 
public class QueueDemo {
  public static void printQ(Queue queue) {
    while(queue.peek() != null)
      System.out.print(queue.remove() + " ");
    System.out.println();
  }
  
  public static void main(String[] args) {  
//Character
    Queue<Character> qc = new LinkedList<Character>();
    for(char c : "Brontosaurus".toCharArray())
      qc.offer(c);
    printQ(qc);
  }
}

我們經常會使用到 toCharArray() 方法，深層次的查看這個方法，我們來探討一下。下面是Java類庫中給出的代碼。

  /**
     * Converts this string to a new character array.
     *
     * @return  a newly allocated character array whose length is the length
     *          of this string and whose contents are initialized to contain
     *          the character sequence represented by this string.
     */
    public char[] toCharArray() {
        // Cannot use Arrays.copyOf because of class initialization order issues
        char result[] = new char[value.length];
        System.arraycopy(value, 0, result, 0, value.length);
        return result;
    }

分析：將一個字符串轉換成一個 Character 型的字符數組，並且這里面的字符是原封不動的拿進去的，意思就是說，包含一切字符均轉換成相應的字符數組。

將上面的程序修改如下【在改字符串中添加一些空格的】

//: holding/QueueDemo.java
// Upcasting to a Queue from a LinkedList.
package holding;
import java.util.*;
 
public class QueueDemo {
  public static void printQ(Queue queue) {
    while(queue.peek() != null)
      System.out.print(queue.remove() + " ");
    System.out.println();
  }
  
  public static void main(String[] args) {  
//Character
    Queue<Character> qc = new LinkedList<Character>();
    for(char c : "Brontosaurus".toCharArray())
      qc.offer(c);
    printQ(qc);
  }
}

得到以下執行效果: