// 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); } /
String is emptyString is not emptyStringNotNullOrEmptyStringIsEmptyStringNotEmpty 旅行图 最后,我们再用mermaid语法绘制一个旅行图,表示我们判断字符串是否为null或者是空字符串的旅程: journey title Journey of String Evaluation section Check String [*] --> IsStringNull: Is null? IsStringNull --> IsS...
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");}}} 1. 2. 3. 4. 5. 6. ...
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{ ...
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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...
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!
if (str != null && !str.trim().isEmpty()) { // 字符串不为空操作 } 集合判空 集合类(如List、Set、Map等)可能为空或者没有元素,通常我们使用isEmpty()来检查: List<String> list = ...; if (list != null && !list.isEmpty()) { ...
checkMapStatus(nonEmptyMap); }publicstaticvoidcheckMapStatus(Map<String, Integer> map){if(map ==null) { System.out.println("The map is null."); }elseif(map.isEmpty()) { System.out.println("The map is empty."); }else{ System.out.println("The map is not null and not empty. Size...
注:app.id是用来标识应用身份的唯一id,格式为string。 1.2.2 Apollo Meta Server Apollo支持应用在不同的环境有不同的配置,所以需要在运行提供给Apollo客户端当前环境的Apollo Meta Server信息。默认情况下,meta server和config service是部署在同一个JVM进程,所以meta server的地址就是config service的地址。