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
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
StringUtils.isBlank()
StringUtils.isBlank(
"\b"
)
=
false
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