java中isEmpty和isBlank的區(qū)別小結(jié)

更新時間：2023年09月01日 10:23:14 作者：小田資料庫

Java中的isEmpty和isBlank都是用來判斷字符串是否為空的方法,但在不同的情況下有所區(qū)別,具有一定的參考價值,感興趣的可以了解一下

干了3年java，代碼中 isEmpty 和 isBlank 的區(qū)別都不知道，一頓瞎用。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(yán)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

/
?*
?*?<p>NOTE:?This?method?changed?in?Lang?version?2.0.
?*?It?no?longer?trims?the?CharSequence.
?*?That?functionality?is?available?in?isBlank().</p>
?*
?*?@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(dāng)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(dāng)于!isAnyEmpty(css) , 必須所有的值都不為空才返回true

/
?*?<p>Checks?if?none?of?the?CharSequences?are?empty?("")?or?null.</p>
?*
?*?<pre>
?*?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
?*?</pre>
?*
?*?@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

/
?*?<p>Checks?if?a?CharSequence?is?whitespace,?empty?("")?or?null.</p>
?*?@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?<?strLen;?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(dāng)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

?/
?*?<p>Checks?if?any?one?of?the?CharSequences?are?blank?("")?or?null?and?not?whitespace?only..</p>
?*?@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

/
?*?<p>Checks?if?none?of?the?CharSequences?are?blank?("")?or?null?and?whitespace?only..</p>
?*?@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);
}