使用String.join(CharSequence delimiter, CharSequence... elements)方法时,如果CharSequence...只有一个元素,结果是什么
时间: 2024-06-13 15:06:39 浏览: 10
当使用String.join(CharSequence delimiter, CharSequence... elements)方法时,如果CharSequence...只有一个元素,那么结果就是该元素本身,不会添加任何分隔符。例如:
```java
String str = String.join(",", "hello");
System.out.println(str); // 输出:hello
```
相关问题
Static member 'java.lang.String.join(java.lang.CharSequence, java.lang.CharSequence...)' accessed via instance reference
The error message "Static member 'java.lang.String.join(java.lang.CharSequence, java.lang.CharSequence...)' accessed via instance reference" occurs when you try to call the static method `join` on an instance of the `String` class instead of calling it on the class itself.
The `join` method is used to join a group of strings together with a delimiter. It takes two parameters: a delimiter and an array of strings. Here is an example of how to use it:
```
String[] words = {"hello", "world", "how", "are", "you"};
String joinedWords = String.join(" ", words);
System.out.println(joinedWords);
```
In this example, we create an array of strings called `words`, and then use the `join` method of the `String` class to join the strings together with a space delimiter.
If you see the error message "Static member 'java.lang.String.join(java.lang.CharSequence, java.lang.CharSequence...)' accessed via instance reference", it means that you are calling the `join` method on an instance of the `String` class, rather than on the class itself. To fix the error, make sure you call the method on the class, like this:
```
String[] words = {"hello", "world", "how", "are", "you"};
String joinedWords = String.join(" ", words);
System.out.println(joinedWords);
```
Note that in the corrected code, we are calling the `join` method on the `String` class itself, not on an instance of the `String` class.
String.join
String.join()是一个Java的字符串操作方法,它用于将一组字符串使用指定的分隔符进行拼接。该方法可以在JDK1.8及以上版本中使用。当被拼接的字符串数组中存在null元素时,方法会将其转换为"null"字符串进行拼接。
以下是一个使用String.join()方法的示例代码:
```
String[] arrs1 = { "this", "is", "java265.com" };
String[] arrs2 = new String = "my";
System.out.println("arrs1:" + String.join(",", arrs1));
System.out.println("arrs2:" + String.join(",", arrs2));
```
运行以上代码,输出如下:
```
arrs1:this,is,java265.com
arrs2:my,null,null
```
String.join()方法有两种语法形式:
1. `public static String join(CharSequence delimiter, CharSequence... elements)`:将一组CharSequence类型的元素使用指定的分隔符进行拼接。
2. `public static String join(CharSequence delimiter, Iterable<? extends CharSequence> elements)`:将一个实现了Iterable接口的CharSequence类型的元素集合使用指定的分隔符进行拼接。
通过调用String.join()方法,可以方便地将一组字符串按照指定的分隔符进行拼接,并返回拼接后的字符串。