isNotEmpty将空格也作为参数,isNotBlank则排除空格参数 StringUtils方法的操作对象是java.lang.String类型的对象,是JDK提供的String类型操作方法的补充,并且是null安全的(即如果输入参数String为null则不会抛出NullPointerException,而是做了相应处理,例如,如果输入为null则返回也是null等,具体可以查看源代码)。 除了构造器,StringUtils中一共有130多个方法,并且都是static的,所以我们可以这样调用StringUtils.xxx() 1. public static boolean isEmpty(String str) 判断某字符串是否为空,为空的标准是str==null或str.length()==0 下面是StringUtils判断是否为空的示例: StringUtils.isEmpty(null) = true StringUtils.isEmpty("") = true StringUtils.isEmpty(" ") = false //注意在StringUtils中空格作非空处理 StringUtils.isEmpty(" ") = false StringUtils.isEmpty("bob") = false StringUtils.isEmpty(" bob ") = false 2. public static boolean isNotEmpty(String str) 判断某字符串是否非空,等于!isEmpty(String str) 下面是示例: StringUtils.isNotEmpty(null) = false StringUtils.isNotEmpty("") = false StringUtils.isNotEmpty(" ") = true StringUtils.isNotEmpty(" ") = true StringUtils.isNotEmpty("bob") = true StringUtils.isNotEmpty(" bob ") = true 3. public static boolean isBlank(String str) 判断某字符串是否为空或长度为0或由空白符(whitespace)构成 下面是示例: StringUtils.isBlank(null) = true StringUtils.isBlank("") = true StringUtils.isBlank(" ") = true StringUtils.isBlank(" ") = true StringUtils.isBlank("\t \n \f \r") = true //对于制表符、换行符、换页符和回车符StringUtils.isBlank()均识为空白符 StringUtils.isBlank("\b") = false //"\b"为单词边界符 StringUtils.isBlank("bob") = false StringUtils.isBlank(" bob ") = false 4. public static boolean isNotBlank(String str) 判断某字符串是否不为空且长度不为0且不由空白符(whitespace)构成,等于!isBlank(String str) 下面是示例: StringUtils.isNotBlank(null) = false StringUtils.isNotBlank("") = false StringUtils.isNotBlank(" ") = false StringUtils.isNotBlank(" ") = false StringUtils.isNotBlank("\t \n \f \r") = false StringUtils.isNotBlank("\b") = true StringUtils.isNotBlank("bob") = true StringUtils.isNotBlank(" bob ") = true 5. public static String trim(String str) 去掉字符串两端的控制符(control characters, char <= 32),如果输入为null则返回null 下面是示例: StringUtils.trim(null) = null StringUtils.trim("") = "" StringUtils.trim(" ") = "" StringUtils.trim(" \b \t \n \f \r ") = "" StringUtils.trim(" \n\tss \b") = "ss" StringUtils.trim(" d d dd ") = "d d dd" StringUtils.trim("dd ") = "dd" StringUtils.trim(" dd ") = "dd" 6. public static String trimToNull(String str) 去掉字符串两端的控制符(control characters, char <= 32),如果变为null或"",则返回null 下面是示例: StringUtils.trimToNull(null) = null StringUtils.trimToNull("") = null StringUtils.trimToNull(" ") = null StringUtils.trimToNull(" \b \t \n \f \r ") = null StringUtils.trimToNull(" \n\tss \b") = "ss" StringUtils.trimToNull(" d d dd ") = "d d dd" StringUtils.trimToNull("dd ") = "dd" StringUtils.trimToNull(" dd ") = "dd" 7. public static String trimToEmpty(String str) 去掉字符串两端的控制符(control characters, char <= 32),如果变为null或"",则返回"" 下面是示例: StringUtils.trimToEmpty(null) = "" StringUtils.trimToEmpty("") = "" StringUtils.trimToEmpty(" ") = "" StringUtils.trimToEmpty(" \b \t \n \f \r ") = "" StringUtils.trimToEmpty(" \n\tss \b") = "ss" StringUtils.trimToEmpty(" d d dd ") = "d d dd" StringUtils.trimToEmpty("dd ") = "dd" StringUtils.trimToEmpty(" dd ") = "dd" 8. public static String strip(String str) 去掉字符串两端的空白符(whitespace),如果输入为null则返回null 下面是示例(注意和trim()的区别): StringUtils.strip(null) = null StringUtils.strip("") = "" StringUtils.strip(" ") = "" StringUtils.strip(" \b \t \n \f \r ") = "\b" StringUtils.strip(" \n\tss \b") = "ss \b" StringUtils.strip(" d d dd ") = "d d dd" StringUtils.strip("dd ") = "dd" StringUtils.strip(" dd ") = "dd" 9. public static String stripToNull(String str) 去掉字符串两端的空白符(whitespace),如果变为null或"",则返回null 下面是示例(注意和trimToNull()的区别): StringUtils.stripToNull(null) = null StringUtils.stripToNull("") = null StringUtils.stripToNull(" ") = null StringUtils.stripToNull(" \b \t \n \f \r ") = "\b" StringUtils.stripToNull(" \n\tss \b") = "ss \b" StringUtils.stripToNull(" d d dd ") = "d d dd" StringUtils.stripToNull("dd ") = "dd" StringUtils.stripToNull(" dd ") = "dd" 10. public static String stripToEmpty(String str) 去掉字符串两端的空白符(whitespace),如果变为null或"",则返回"" 下面是示例(注意和trimToEmpty()的区别): StringUtils.stripToNull(null) = "" StringUtils.stripToNull("") = "" StringUtils.stripToNull(" ") = "" StringUtils.stripToNull(" \b \t \n \f \r ") = "\b" StringUtils.stripToNull(" \n\tss \b") = "ss \b" StringUtils.stripToNull(" d d dd ") = "d d dd" StringUtils.stripToNull("dd ") = "dd" StringUtils.stripToNull(" dd ") = "dd"

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