Learn how to effectively check if a Java string is null, empty, and whitespace. Enhance code reliability and prevent errors. Master string validation in Java now!
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// 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...
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...
importorg.apache.commons.lang3.StringUtils;publicclassStringCheckExample{publicstaticvoidmain(String[]args){Stringstr="";// 创建一个空字符串if(StringUtils.isEmpty(str)){System.out.println("str is empty or null");}else{System.out.println("str is not empty");}}} ...
if(str.trim().isEmpty()){// 字符串为空} 1. 2. 3. 这段代码使用了String类的trim()方法来去除字符串两端的空格,并使用isEmpty()方法来判断字符串是否为空。 代码示例 下面是一个完整的示例代码,展示了如何判断字符串是否为空或null: publicclassStringNullCheckExample{publicstaticvoidmain(String[]args...
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."); ...
public class StringCheck { public static void main(String[] args) { String str1 = null; String str2 = ""; String str3 = "Hello, World!"; // 判断字符串是否为null if (str1 == null) { System.out.println("str1 is null"); } // 判断字符串是否为空 if (str2.isEmpty()) { Sy...
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."); ...
在Java中,可以使用`==`运算符或者`Objects.isNull()`方法来检查对象是否为空。1. 使用`==`运算符:```javaObject obj = null;if (o...