全面认识lang3包

最新推荐文章于 2025-05-11 02:35:01 发布

jilanting

最新推荐文章于 2025-05-11 02:35:01 发布

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分类专栏：基础文章标签：字符串判空集合判空 lang3 java

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jar包：

<dependency>
    <groupId>org.apache.commons</groupId>
    <artifactId>commons-lang3</artifactId>
    <version>3.9</version>
</dependency>

1、StringUtils判空方法

源码

 
public static boolean isBlank(CharSequence cs) {
    int strLen;
    if (cs != null && (strLen = cs.length()) != 0) {
        for(int i = 0; i < strLen; ++i) {
          if (!Character.isWhitespace(cs.charAt(i))) {
             return false;
           }
        }
       return true;
     } else {
        return true;
    }
}

public static boolean isEmpty(CharSequence cs) {
    return cs == null || cs.length() == 0;
}

String strNull = null;
System.out.println("strNull isBlank：" + StringUtils.isBlank(strNull) + ",isEmpty:" + StringUtils.isEmpty(strNull));
String str = "";
System.out.println("str\"\" isBlank：" + StringUtils.isBlank(str) + ",isEmpty:" + StringUtils.isEmpty(str));
String strKongge = " ";
System.out.println("strKongge isBlank：" + StringUtils.isBlank(strKongge) + ",isEmpty:" + StringUtils.isEmpty(strKongge));
String strEmPTY = StringUtils.EMPTY;
System.out.println("strEmPTY isBlank：" + StringUtils.isBlank(strEmPTY) + ",isEmpty:" + StringUtils.isEmpty(strEmPTY));
String strSpe1 = "\t";
System.out.println("strSpe1\\t isBlank：" + StringUtils.isBlank(strSpe1) + ",isEmpty:" + StringUtils.isEmpty(strSpe1));
String strSpe2 = "\n";
System.out.println("strSpe2\\n isBlank：" + StringUtils.isBlank(strSpe2) + ",isEmpty:" + StringUtils.isEmpty(strSpe2));
String strSpe3 = "\n\t";
System.out.println("strSpe3\\n\\t isBlank：" + StringUtils.isBlank(strSpe3) + ",isEmpty:" + StringUtils.isEmpty(strSpe3));

strNull isBlank：true,isEmpty:true
str"" isBlank：true,isEmpty:true
strKongge isBlank：true,isEmpty:false
strEmPTY isBlank：true,isEmpty:true
strSpe1\t isBlank：true,isEmpty:false
strSpe2\n isBlank：true,isEmpty:false
strSpe3\n\t isBlank：true,isEmpty:false

2、集合判空CollectionUtils.isEmpty

jar包：

public static boolean isEmpty(Collection coll) {
   return (coll == null || coll.isEmpty());
}