Example 1: Check if String is Empty or Null class Main { public static void main(String[] args) { // create null, empty, and regular strings String str1 = null; String str2 = ""; String str3 = " "; // check if str1 is null or empty System.out.println("str1 is " + is...
StringUtils.isBlank(str):检查字符串是否为null、空或只包含空白字符(如空格、制表符、换行符等)。 import org.apache.commons.lang3.StringUtils; String str = null; // 或者 "" if (StringUtils.isEmpty(str)) { System.out.println("String is null or empty"); } str = " "; // 空白字符串 if ...
示例 importorg.apache.commons.lang3.StringUtils;publicclassStringTest{publicstaticvoidmain(String[]args){Stringstr1=null;Stringstr2="";Stringstr3=" ";// 方法1: 使用 == 和 isEmpty()if(str1==null||str1.isEmpty()){System.out.println("str1 is null or empty");}if(str2==null||str2....
publicclassStringCheckExample{publicstaticvoidmain(String[] args){// 定义一个可能为null或空的String变量StringmyString=null;// 我们可以根据需要更改这个变量的值// 判断String是否为null或空if(myString ==null|| myString.isEmpty()) { System.out.println("The string is null or empty."); }else{ ...
// 判断String是否为null或空 if(myString ==null|| myString.isEmpty) { System.out.println("The string is null or empty."); }else{ System.out.println("The string is not null and not empty. Its value is: "+ myString); } // 注意:如果myString是null,直接调用myString.isEmpty会抛出Nu...
publicclassStringCheckExample{publicstaticvoidmain(String[] args){// 定义一个可能为null或空的String变量StringmyString=null;// 我们可以根据需要更改这个变量的值// 判断String是否为null或空if(myString ==null|| myString.isEmpty()) { System.out.println("The string is null or empty."); ...
{if(String.IsNullOrEmpty(s))return"is null or empty";elsereturnString.Format("(\"{0}\") is neither null nor empty", s); } }//The example displays the following output://String s1 ("abcd") is neither null nor empty.//String s2 is null or empty.//String s3 is null or empty....
object EmptyStringExtensions { extension (str: String) def isEmptyOrWhitespace: Boolean = str.trim.isEmpty def isNullOrEmptyOrWhitespace: Boolean = str == null || str.isEmptyOrWhitespace } We must import EmptyStringExtensions to use the methods we defined above: import EmptyStringExtensions._ cl...
, Test(s3)); String Test(string s) { if (String.IsNullOrEmpty(s)) return "is null or empty"; else return String.Format("(\"{0}\") is neither null nor empty", s); } // The example displays the following output: // String s1 ("abcd") is neither null nor empty. // String ...
public class NullOrEmptyCheckExample { public static void main(String[] args) { String str1 = null; String str2 = ""; String str3 = "Hello, World!"; // Check if str1 is null or empty if (str1 == null || str1.length() == 0) { System.out.println("str1 is null or empty...