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...
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."); } else { System.out.println(...
// 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...
下面给出一个简单的示例代码,演示如何判断一个字符串是否为null或者是空字符串: AI检测代码解析 publicclassMain{publicstaticvoidmain(String[]args){Stringstr1=null;Stringstr2="";Stringstr3="Hello";if(str1!=null&&!str1.isEmpty()){System.out.println("str1 is not null or empty");}else{System....
最简单的方法是使用if语句结合逻辑运算符。代码示例如下: publicclassStringCheck{publicstaticbooleanisEmptyOrNull(Stringstr){returnstr==null||str.isEmpty();}publicstaticvoidmain(String[]args){StringtestString=null;System.out.println("Is string empty or null? "+isEmptyOrNull(testString));// 输出:...
Check if String is Null or Empty in Java Java: Check if String is Numeric How to Convert String to int in Java Reverse a String in Java Convert int to String in Java How to Split a String in Java: Different Examples Convert Char to String in Java ...
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."); ...
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."); ...
翻一下JDK的实现就会知道：其实isEmpty完全等同于string.length()==0如果String本身是null，那么使用...
我们可以结合上述方法来综合判断一个Map是否为null或者空: (1)综合检查: Map<String, Integer> map = getSomeMap();// 假设这是从某个方法获取的Mapif(map ==null|| map.isEmpty()) { System.out.println("Map is null or empty"); }else{ ...