isEmpty 和 isBlank 的用法區(qū)別，居然一半的人答不上來.....
來源：blog.csdn.net/moshowgame/article/details/102914895
也許你兩個都不知道,也許你除了isEmpty/isNotEmpty/isNotBlank/isBlank外,并不知道還有isAnyEmpty/isNoneEmpty/isAnyBlank/isNoneBlank的存在, come on ,讓我們一起來探索org.apache.commons.lang3.StringUtils;這個工具類.
?
isEmpty系列
StringUtils.isEmpty()
是否為空. 可以看到 " " 空格是會繞過這種空判斷,因為是一個空格,并不是嚴格的空值,會導(dǎo)致?isEmpty(" ")=false
StringUtils.isEmpty(null)?=?true
StringUtils.isEmpty("")?=?true
StringUtils.isEmpty("?")?=?false
StringUtils.isEmpty(“bob”)?=?false
StringUtils.isEmpty("?bob?")?=?false
/**
?*
?*?NOTE:?This?method?changed?in?Lang?version?2.0.
?*?It?no?longer?trims?the?CharSequence.
?*?That?functionality?is?available?in?isBlank().
?*
?*?@param?cs??the?CharSequence?to?check,?may?be?null
?*?@return?{@code?true}?if?the?CharSequence?is?empty?or?null
?*?@since?3.0?Changed?signature?from?isEmpty(String)?to?isEmpty(CharSequence)
?*/
public?static?boolean?isEmpty(final?CharSequence?cs)?{
????return?cs?==?null?||?cs.length()?==?0;
}
StringUtils.isNotEmpty()
相當于不為空 ,?= !isEmpty()
public?static?boolean?isNotEmpty(final?CharSequence?cs)?{
????????return?!isEmpty(cs);
????}
StringUtils.isAnyEmpty()
是否有一個為空,只有一個為空,就為true.
StringUtils.isAnyEmpty(null)?=?true
StringUtils.isAnyEmpty(null,?“foo”)?=?true
StringUtils.isAnyEmpty("",?“bar”)?=?true
StringUtils.isAnyEmpty(“bob”,?“”)?=?true
StringUtils.isAnyEmpty("?bob?",?null)?=?true
StringUtils.isAnyEmpty("?",?“bar”)?=?false
StringUtils.isAnyEmpty(“foo”,?“bar”)?=?false
/**
?*?@param?css??the?CharSequences?to?check,?may?be?null?or?empty
?*?@return?{@code?true}?if?any?of?the?CharSequences?are?empty?or?null
?*?@since?3.2
?*/
public?static?boolean?isAnyEmpty(final?CharSequence...?css)?{
??if?(ArrayUtils.isEmpty(css))?{
????return?true;
??}
??for?(final?CharSequence?cs?:?css){
????if?(isEmpty(cs))?{
??????return?true;
????}
??}
??return?false;
}
StringUtils.isNoneEmpty()
相當于!isAnyEmpty(css)?, 必須所有的值都不為空才返回true
/**
?*?Checks?if?none?of?the?CharSequences?are?empty?("")?or?null.
?*
?*?
?*?StringUtils.isNoneEmpty(null)?????????????=?false
?*?StringUtils.isNoneEmpty(null,?"foo")??????=?false
?*?StringUtils.isNoneEmpty("",?"bar")????????=?false
?*?StringUtils.isNoneEmpty("bob",?"")????????=?false
?*?StringUtils.isNoneEmpty("??bob??",?null)??=?false
?*?StringUtils.isNoneEmpty("?",?"bar")???????=?true
?*?StringUtils.isNoneEmpty("foo",?"bar")?????=?true
?*?
?*
?*?@param?css??the?CharSequences?to?check,?may?be?null?or?empty
?*?@return?{@code?true}?if?none?of?the?CharSequences?are?empty?or?null
?*?@since?3.2
?*/
public?static?boolean?isNoneEmpty(final?CharSequence...?css)?{
?
isBank系列
StringUtils.isBlank()
是否為真空值(空格或者空值)
StringUtils.isBlank(null)?=?true
StringUtils.isBlank("")?=?true
StringUtils.isBlank("?")?=?true
StringUtils.isBlank(“bob”)?=?false
StringUtils.isBlank("?bob?")?=?false
/**
?*?Checks?if?a?CharSequence?is?whitespace,?empty?("")?or?null.
?*?@param?cs??the?CharSequence?to?check,?may?be?null
?*?@return?{@code?true}?if?the?CharSequence?is?null,?empty?or?whitespace
?*?@since?2.0
?*?@since?3.0?Changed?signature?from?isBlank(String)?to?isBlank(CharSequence)
?*/
public?static?boolean?isBlank(final?CharSequence?cs)?{
????int?strLen;
????if?(cs?==?null?||?(strLen?=?cs.length())?==?0)?{
????????return?true;
????}
????for?(int?i?=?0;?i?????????if?(Character.isWhitespace(cs.charAt(i))?==?false)?{
????????????return?false;
????????}
????}
????return?true;
}
StringUtils.isNotBlank()
是否真的不為空,不是空格或者空值 ,相當于!isBlank();
public?static?boolean?isNotBlank(final?CharSequence?cs)?{
????????return?!isBlank(cs);
????}
StringUtils.isAnyBlank()
是否包含任何真空值(包含空格或空值)
StringUtils.isAnyBlank(null)?=?true
StringUtils.isAnyBlank(null,?“foo”)?=?true
StringUtils.isAnyBlank(null,?null)?=?true
StringUtils.isAnyBlank("",?“bar”)?=?true
StringUtils.isAnyBlank(“bob”,?“”)?=?true
StringUtils.isAnyBlank("?bob?",?null)?=?true
StringUtils.isAnyBlank("?",?“bar”)?=?true
StringUtils.isAnyBlank(“foo”,?“bar”)?=?false
?/**
?*?Checks?if?any?one?of?the?CharSequences?are?blank?("")?or?null?and?not?whitespace?only..
?*?@param?css??the?CharSequences?to?check,?may?be?null?or?empty
?*?@return?{@code?true}?if?any?of?the?CharSequences?are?blank?or?null?or?whitespace?only
?*?@since?3.2
?*/
public?static?boolean?isAnyBlank(final?CharSequence...?css)?{
??if?(ArrayUtils.isEmpty(css))?{
????return?true;
??}
??for?(final?CharSequence?cs?:?css){
????if?(isBlank(cs))?{
??????return?true;
????}
??}
??return?false;
}
StringUtils.isNoneBlank()
是否全部都不包含空值或空格
StringUtils.isNoneBlank(null)?=?false
StringUtils.isNoneBlank(null,?“foo”)?=?false
StringUtils.isNoneBlank(null,?null)?=?false
StringUtils.isNoneBlank("",?“bar”)?=?false
StringUtils.isNoneBlank(“bob”,?“”)?=?false
StringUtils.isNoneBlank("?bob?",?null)?=?false
StringUtils.isNoneBlank("?",?“bar”)?=?false
StringUtils.isNoneBlank(“foo”,?“bar”)?=?true
/**
?*?Checks?if?none?of?the?CharSequences?are?blank?("")?or?null?and?whitespace?only..
?*?@param?css??the?CharSequences?to?check,?may?be?null?or?empty
?*?@return?{@code?true}?if?none?of?the?CharSequences?are?blank?or?null?or?whitespace?only
?*?@since?3.2
?*/
public?static?boolean?isNoneBlank(final?CharSequence...?css)?{
??return?!isAnyBlank(css);
}
?
StringUtils的其他方法
可以參考官方的文檔,里面有詳細的描述,有些方法還是很好用的.
https://commons.apache.org/proper/commons-lang/apidocs/org/apache/commons/lang3/StringUtils.html
（感謝閱讀，希望對你所有幫助)
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好文章，我在看??