The SHA-256 algorithm is a widely used hash method producing a 256-bit hash value. This post will discuss different methods to generate the SHA-256 hashcode in Java using
MessageDigest
class, Guava, and Apache Commons library.
1. Using
MessageDigest
class
The idea is to get an instance of SHA-256 message digest using the
java.security.MessageDigest
class
getInstance()
method, which takes digest algorithm. Then we call the
digest(input)
method that first calls
update(input)
, passing the input array to the update method, then calls
digest()
. We can make an explicit call to the
update()
method several times for large inputs.
Note that the
java.xml.bind
is no longer contained on the default classpath starting Java SE 9. In Java 11, they are completely removed from the JDK.
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import
javax
.
xml
.
bind
.
DatatypeConverter
;
import
java
.
nio
.
charset
.
StandardCharsets
;
import
java
.
security
.
MessageDigest
;
class
Main
{
public
static
void
main
(
String
[
]
args
)
throws
Exception
{
String
password
=
"SHA-256"
;
MessageDigest
md
=
MessageDigest
.
getInstance
(
"SHA-256"
)
;
byte
[
]
digest
=
md
.
digest
(
password
.
getBytes
(
StandardCharsets
.
UTF_8
)
)
;
String
sha256
=
DatatypeConverter
.
printHexBinary
(
digest
)
.
toLowerCase
(
)
;
// print SHA-256 Message Digest
System
.
out
.
println
(
sha256
)
;
}
}
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import
com
.
google
.
common
.
base
.
Charsets
;
import
com
.
google
.
common
.
hash
.
HashCode
;
import
com
.
google
.
common
.
hash
.
Hasher
;
import
com
.
google
.
common
.
hash
.
Hashing
;
class
Main
{
public
static
void
main
(
String
[
]
args
)
throws
Exception
{
String
password
=
"SHA-256"
;
Hasher
hasher
=
Hashing
.
sha256
(
)
.
newHasher
(
)
;
hasher
.
putString
(
password
,
Charsets
.
UTF_8
)
;
HashCode
sha256
=
hasher
.
hash
(
)
;
System
.
out
.
println
(
sha256
)
;
}
}
bbd07c4fc02c99b97124febf42c7b63b5011c0df28d409fbb486b5a9d2e615ea
3. Using Apache Commons Lang
Alternatively, Apache Commons library can also be used which provides
org.apache.commons.codec.digest.DigestUtils
class to replace
MessageDigest
Class.
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import
org
.
apache
.
commons
.
codec
.
digest
.
DigestUtils
;
class
Main
{
public
static
void
main
(
String
[
]
args
)
throws
Exception
{
String
password
=
"SHA-256"
;
String
sha256
=
DigestUtils
.
sha256Hex
(
password
)
;
System
.
out
.
println
(
sha256
)
;
}
}
bbd07c4fc02c99b97124febf42c7b63b5011c0df28d409fbb486b5a9d2e615ea
That’s all about generating the SHA-256 hashcode in Java.
