Java 找不到任何数组的符号？

Question

所以，这很烦人。

我制作了 2 个程序。

#1:

class Arrays2 {
public static void main(String[] args){

    String sentenceBest[] = {"This is the first sentence!"};

    char chR[] = sentenceBest.toCharArray();        

    for (int counter = 0; counter < chR.length; counter++){
        char now = chR[counter];
        if (now != ' ') {
            System.out.println(now);
        }else {
            System.out.println('.');
        }
    }



}
  }

对于这个程序，它说:

Arrays_ToCjarArray(not working).java:6: cannot find symbol
symbol  : method toCharArray()
location: class java.lang.String[]
char chR[] = sentenceBest.toCharArray();        
                             ^
 1 error

#2 计划:

class Arrays_3 {
public static void main(String[] args){

    boolean numbers[] [] = new boolean[10] [10];

    numbers[9] [8] = true;

    System.out.println(numbers[9][8] + "!!!");


    String names[] = {"Marton", "Balint", "Thomas", "David", "John", "Peter", "Andy", "Daniel", "Josh", "James", "Erling", "Romeo", "Vincent", "Fabian"};

    System.out.println("The origional order: ");
    for (int counter = 0; counter < names.length; counter++){
        String newName = names[counter];
        System.out.println(counter + ": " + newName);
    }


    System.out.println("The Alphabetical order: ");

    Arrays

    for (int counter2 = 0; counter2 < names.length; counter2++) {
        System.out.println(counter2 + ": " + names);
    }


}
       }

同样的事情。找不到标志。太烦人了。

Arrays_3.java:21: cannot find symbol
symbol  : variable Arrays
location: class Arrays_3
Arrays.sort(names);
    ^
1 error

我真的不明白这一点，因为这个源代码来自一本很棒的书(到目前为止)，书名是 Sams 在 24 小时内教你 Java。所以我真的不明白这一点。我们将不胜感激任何帮助。

Answer 1

1. toCharArray()适用于 String 而不是 String[]

2.你需要导入Arrays通过添加

import java.util.Arrays;