Java 中 array 用法
Java
|
1
2
3
|
String
[
]
aArray
=
new
String
[
5
]
;
String
[
]
bArray
=
{
"a"
,
"b"
,
"c"
,
"d"
,
"e"
}
;
String
[
]
cArray
=
new
String
[
]
{
"a"
,
"b"
,
"c"
,
"d"
,
"e"
}
;
|
1.Java中打印数组
Java
|
1
2
3
4
5
6
7
8
9
|
int
[
]
intArray
=
{
1
,
2
,
3
,
4
,
5
}
;
String
intArrayString
=
Arrays
.
toString
(
intArray
)
;
// print directly will print reference value
System
.
out
.
println
(
intArray
)
;
// [I@7150bd4d
System
.
out
.
println
(
intArrayString
)
;
// [1, 2, 3, 4, 5]
|
2.用数组创建一个ArrayList
Java
|
1
2
3
4
|
String
[
]
stringArray
=
{
"a"
,
"b"
,
"c"
,
"d"
,
"e"
}
;
ArrayList
<
String
>
arrayList
=
new
ArrayList
<
String
>
(
Arrays
.
asList
(
stringArray
)
)
;
System
.
out
.
println
(
arrayList
)
;
// [A，B，C，D，E]
|
3，检查数组中是否包含特定的值
Java
|
1
2
3
|
String
[
]
stringArray
=
{
"a"
,
"b"
,
"c"
,
"d"
,
"e"
}
;
boolean
b
=
Arrays
.
asList
(
stringArray
)
.
contains
(
"a"
)
;
System
.
out
.
println
(
b
)
;
|
4.结合两个数组
Java
|
1
2
3
4
|
int
[
]
intArray
=
{
1
,
2
,
3
,
4
,
5
}
;
int
[
]
intArray2
=
{
6
,
7
,
8
,
9
,
10
}
;
// Apache Commons Lang library
int
[
]
combinedIntArray
=
ArrayUtils
.
addAll
(
intArray
,
intArray2
)
;
|
5.声明一个数组的方法
Java
|
1
|
method
(
new
String
[
]
{
"a"
,
"b"
,
"c"
,
"d"
,
"e"
}
)
;
|
6，加入所提供的数组中的元素连接成一个字符串
Java
|
1
2
3
4
5
|
// containing the provided list of elements
// Apache common lang
String
j
=
StringUtils
.
join
(
new
String
[
]
{
"a"
,
"b"
,
"c"
}
,
", "
)
;
System
.
out
.
println
(
j
)
;
// a, b, c
|
7. Array与List之间的转换
Java
|
1
2
3
4
5
6
|
String
[
]
stringArray
=
{
"a"
,
"b"
,
"c"
,
"d"
,
"e"
}
;
ArrayList
String
[
]
stringArr
=
new
String
[
arrayList
.
size
(
)
]
;
arrayList
.
toArray
(
stringArr
)
;
for
(
String
s
:
stringArr
)
System
.
out
.
println
(
s
)
;
|
8.数组转换成set
Java
|
1
2
3
|
Set
System
.
out
.
println
(
set
)
;
//[d, e, b, c, a]
|
9.数组反向输出
Java
|
1
2
3
4
|
int
[
]
intArray
=
{
1
,
2
,
3
,
4
,
5
}
;
ArrayUtils
.
reverse
(
intArray
)
;
System
.
out
.
println
(
Arrays
.
toString
(
intArray
)
)
;
//[5, 4, 3, 2, 1]
|
10.删除数组元素
Java
|
1
2
3
|
int
[
]
intArray
=
{
1
,
2
,
3
,
4
,
5
}
;
int
[
]
removed
=
ArrayUtils
.
removeElement
(
intArray
,
3
)
;
//create a new array
System
.
out
.
println
(
Arrays
.
toString
(
removed
)
)
;
|
最后一下int转换成byte数组
Java
|
1
2
3
4
5
|
byte
[
]
bytes
=
ByteBuffer
.
allocate
(
4
)
.
putInt
(
8
)
.
array
(
)
;
for
(
byte
t
:
bytes
)
{
System
.
out
.
format
(
"0x%x "
,
t
)
;
}
|
|
1
2
3
|
String
[
]
aArray
=
new
String
[
5
]
;
String
[
]
bArray
=
{
"a"
,
"b"
,
"c"
,
"d"
,
"e"
}
;
String
[
]
cArray
=
new
String
[
]
{
"a"
,
"b"
,
"c"
,
"d"
,
"e"
}
;
|
1.Java中打印数组
Java
|
1
2
3
4
5
6
7
8
9
|
int
[
]
intArray
=
{
1
,
2
,
3
,
4
,
5
}
;
String
intArrayString
=
Arrays
.
toString
(
intArray
)
;
// print directly will print reference value
System
.
out
.
println
(
intArray
)
;
// [I@7150bd4d
System
.
out
.
println
(
intArrayString
)
;
// [1, 2, 3, 4, 5]
|
2.用数组创建一个ArrayList
Java
|
1
2
3
4
|
String
[
]
stringArray
=
{
"a"
,
"b"
,
"c"
,
"d"
,
"e"
}
;
ArrayList
<
String
>
arrayList
=
new
ArrayList
<
String
>
(
Arrays
.
asList
(
stringArray
)
)
;
System
.
out
.
println
(
arrayList
)
;
// [A，B，C，D，E]
|
3，检查数组中是否包含特定的值
Java
|
1
2
3
|
String
[
]
stringArray
=
{
"a"
,
"b"
,
"c"
,
"d"
,
"e"
}
;
boolean
b
=
Arrays
.
asList
(
stringArray
)
.
contains
(
"a"
)
;
System
.
out
.
println
(
b
)
;
|
4.结合两个数组
Java
|
1
2
3
4
|
int
[
]
intArray
=
{
1
,
2
,
3
,
4
,
5
}
;
int
[
]
intArray2
=
{
6
,
7
,
8
,
9
,
10
}
;
// Apache Commons Lang library
int
[
]
combinedIntArray
=
ArrayUtils
.
addAll
(
intArray
,
intArray2
)
;
|
5.声明一个数组的方法
Java
|
1
|
method
(
new
String
[
]
{
"a"
,
"b"
,
"c"
,
"d"
,
"e"
}
)
;
|
6，加入所提供的数组中的元素连接成一个字符串
Java
|
1
2
3
4
5
|
// containing the provided list of elements
// Apache common lang
String
j
=
StringUtils
.
join
(
new
String
[
]
{
"a"
,
"b"
,
"c"
}
,
", "
)
;
System
.
out
.
println
(
j
)
;
// a, b, c
|
7. Array与List之间的转换
Java
|
1
2
3
4
5
6
|
String
[
]
stringArray
=
{
"a"
,
"b"
,
"c"
,
"d"
,
"e"
}
;
ArrayList
String
[
]
stringArr
=
new
String
[
arrayList
.
size
(
)
]
;
arrayList
.
toArray
(
stringArr
)
;
for
(
String
s
:
stringArr
)
System
.
out
.
println
(
s
)
;
|
8.数组转换成set
Java
|
1
2
3
|
Set
System
.
out
.
println
(
set
)
;
//[d, e, b, c, a]
|
9.数组反向输出
Java
|
1
2
3
4
|
int
[
]
intArray
=
{
1
,
2
,
3
,
4
,
5
}
;
ArrayUtils
.
reverse
(
intArray
)
;
System
.
out
.
println
(
Arrays
.
toString
(
intArray
)
)
;
//[5, 4, 3, 2, 1]
|
10.删除数组元素
Java
|
1
2
3
|
int
[
]
intArray
=
{
1
,
2
,
3
,
4
,
5
}
;
int
[
]
removed
=
ArrayUtils
.
removeElement
(
intArray
,
3
)
;
//create a new array
System
.
out
.
println
(
Arrays
.
toString
(
removed
)
)
;
|
最后一下int转换成byte数组
Java
|
1
2
3
4
5
|
byte
[
]
bytes
=
ByteBuffer
.
allocate
(
4
)
.
putInt
(
8
)
.
array
(
)
;
for
(
byte
t
:
bytes
)
{
System
.
out
.
format
(
"0x%x "
,
t
)
;
}
|