URLDecoder
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Utility class for HTML form decoding. This class contains static methods
for decoding a String from the application/x-www-form-urlencoded
MIME format.
The conversion process is the reverse of that used by the URLEncoder class. It is assumed
that all characters in the encoded string are one of the following:
"a
" through "z
",
"A
" through "Z
",
"0
" through "9
", and
"-
", "_
",
".
", and "*
". The
character "%
" is allowed but is interpreted
as the start of a special escaped sequence.
The following rules are applied in the conversion:
- The alphanumeric characters "
a
" through
"z
", "A
" through
"Z
" and "0
"
through "9
" remain the same.
- The special characters "
.
",
"-
", "*
", and
"_
" remain the same.
- The plus sign "
+
" is converted into a
space character " " .
- A sequence of the form "
%xy
" will be
treated as representing a byte where xy is the two-digit
hexadecimal representation of the 8 bits. Then, all substrings
that contain one or more of these byte sequences consecutively
will be replaced by the character(s) whose encoding would result
in those consecutive bytes.
The encoding scheme used to decode these characters may be specified,
or if unspecified, the default encoding of the platform will be used.
There are two possible ways in which this decoder could deal with
illegal strings. It could either leave illegal characters alone or
it could throw an IllegalArgumentException
.
Which approach the decoder takes is left to the
implementation.
Public Constructor Summary
Public Method Summary
static
String
|
decode( String s)
This method is deprecated.
The resulting string may vary depending on the platform's
default encoding. Instead, use the decode(String,String) method
to specify the encoding.
|
static
String
|
decode( String s, String enc)
Decodes a application/x-www-form-urlencoded string using a specific
encoding scheme.
|
Inherited Method Summary
From class
java.lang.Object
Object
|
clone()
Creates and returns a copy of this Object .
|
boolean
|
equals( Object obj)
Compares this instance with the specified object and indicates if they
are equal.
|
void
|
finalize()
Invoked when the garbage collector has detected that this instance is no longer reachable.
|
final
Class<?>
|
getClass()
Returns the unique instance of Class that represents this
object's class.
|
int
|
hashCode()
Returns an integer hash code for this object.
|
final
void
|
notify()
Causes a thread which is waiting on this object's monitor (by means of
calling one of the wait() methods) to be woken up.
|
final
void
|
notifyAll()
Causes all threads which are waiting on this object's monitor (by means
of calling one of the wait() methods) to be woken up.
|
String
|
toString()
Returns a string containing a concise, human-readable description of this
object.
|
final
void
|
wait(long timeout, int nanos)
Causes the calling thread to wait until another thread calls the notify() or notifyAll() method of this object or until the
specified timeout expires.
|
final
void
|
wait(long timeout)
Causes the calling thread to wait until another thread calls the notify() or notifyAll() method of this object or until the
specified timeout expires.
|
final
void
|
wait()
Causes the calling thread to wait until another thread calls the notify() or notifyAll() method of this object.
|
Public Methods
public
static
String
decode
(String s)
This method is deprecated.
The resulting string may vary depending on the platform's
default encoding. Instead, use the decode(String,String) method
to specify the encoding.
Decodes a x-www-form-urlencoded
string.
The platform's default encoding is used to determine what characters
are represented by any consecutive sequences of the form
"%xy
".
Decodes a application/x-www-form-urlencoded
string using a specific
encoding scheme.
The supplied encoding is used to determine
what characters are represented by any consecutive sequences of the
form "%xy
".
Note: The
World Wide Web Consortium Recommendation states that
UTF-8 should be used. Not doing so may introduce
incompatibilities.
Except as otherwise noted, the content of this page is licensed under the Creative Commons Attribution 4.0 License, and code samples are licensed under the Apache 2.0 License. For details, see the Google Developers Site Policies. Java is a registered trademark of Oracle and/or its affiliates.
Last updated 2024-07-10 UTC.
[[["Easy to understand","easyToUnderstand","thumb-up"],["Solved my problem","solvedMyProblem","thumb-up"],["Other","otherUp","thumb-up"]],[["Missing the information I need","missingTheInformationINeed","thumb-down"],["Too complicated / too many steps","tooComplicatedTooManySteps","thumb-down"],["Out of date","outOfDate","thumb-down"],["Samples / code issue","samplesCodeIssue","thumb-down"],["Other","otherDown","thumb-down"]],["Last updated 2024-07-10 UTC."],[[["\u003cp\u003e\u003ccode\u003eURLDecoder\u003c/code\u003e is a utility class in Java used for decoding HTML form data encoded in the \u003ccode\u003eapplication/x-www-form-urlencoded\u003c/code\u003e MIME format.\u003c/p\u003e\n"],["\u003cp\u003eIt reverses the encoding process performed by the \u003ccode\u003eURLEncoder\u003c/code\u003e class, converting encoded characters back to their original form.\u003c/p\u003e\n"],["\u003cp\u003e\u003ccode\u003eURLDecoder\u003c/code\u003e provides two \u003ccode\u003edecode()\u003c/code\u003e methods: one using the platform's default encoding (deprecated) and another allowing you to specify the encoding scheme.\u003c/p\u003e\n"],["\u003cp\u003eDecoding involves converting escape sequences (like \u003ccode\u003e%xy\u003c/code\u003e) to their corresponding characters and replacing '+' with spaces.\u003c/p\u003e\n"],["\u003cp\u003eWhile implementations can handle illegal strings differently, UTF-8 encoding is recommended for compatibility with the World Wide Web Consortium standards.\u003c/p\u003e\n"]]],["The `URLDecoder` class decodes strings from the `application/x-www-form-urlencoded` format. It converts alphanumeric characters, \".\", \"-\", \"*\", and \"_\" directly. \"+\" is decoded to a space. \"%xy\" sequences are treated as byte representations, decoded based on a specified encoding or the platform's default. The class provides a deprecated `decode(String)` method, and `decode(String, String)` for encoding specification. It can leave illegal characters untouched or throw an exception.\n"],null,["# URLDecoder\n\npublic class **URLDecoder** extends [Object](../../../reference/java/lang/Object.html) \nUtility class for HTML form decoding. This class contains static methods\nfor decoding a String from the `application/x-www-form-urlencoded`\nMIME format.\n\n\nThe conversion process is the reverse of that used by the URLEncoder class. It is assumed\nthat all characters in the encoded string are one of the following:\n\"`a`\" through \"`z`\",\n\"`A`\" through \"`Z`\",\n\"`0`\" through \"`9`\", and\n\"`-`\", \"`_`\",\n\"`.`\", and \"`*`\". The\ncharacter \"`%`\" is allowed but is interpreted\nas the start of a special escaped sequence.\n\n\nThe following rules are applied in the conversion:\n\n- The alphanumeric characters \"`a`\" through \"`z`\", \"`A`\" through \"`Z`\" and \"`0`\" through \"`9`\" remain the same.\n- The special characters \"`.`\", \"`-`\", \"`*`\", and \"`_`\" remain the same.\n- The plus sign \"`+`\" is converted into a space character \" \" .\n- A sequence of the form \"*`%xy`* \" will be treated as representing a byte where *xy* is the two-digit hexadecimal representation of the 8 bits. Then, all substrings that contain one or more of these byte sequences consecutively will be replaced by the character(s) whose encoding would result in those consecutive bytes. The encoding scheme used to decode these characters may be specified, or if unspecified, the default encoding of the platform will be used.\n\n\nThere are two possible ways in which this decoder could deal with\nillegal strings. It could either leave illegal characters alone or\nit could throw an [IllegalArgumentException](../../../reference/java/lang/IllegalArgumentException.html).\nWhich approach the decoder takes is left to the\nimplementation. \n\n### Public Constructor Summary\n\n|---|--------------------------------------------------------------------------|\n| | [URLDecoder](../../../reference/java/net/URLDecoder.html#URLDecoder())() |\n\n### Public Method Summary\n\n|-----------------------------------------------------------|----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|\n| static [String](../../../reference/java/lang/String.html) | [decode](../../../reference/java/net/URLDecoder.html#decode(java.lang.String))([String](../../../reference/java/lang/String.html) s) *This method is deprecated. The resulting string may vary depending on the platform's default encoding. Instead, use the decode(String,String) method to specify the encoding.* |\n| static [String](../../../reference/java/lang/String.html) | [decode](../../../reference/java/net/URLDecoder.html#decode(java.lang.String,%20java.lang.String))([String](../../../reference/java/lang/String.html) s, [String](../../../reference/java/lang/String.html) enc) Decodes a `application/x-www-form-urlencoded` string using a specific encoding scheme. |\n\n### Inherited Method Summary\n\nFrom class [java.lang.Object](../../../reference/java/lang/Object.html) \n\n|-------------------------------------------------------------|--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|\n| [Object](../../../reference/java/lang/Object.html) | [clone](../../../reference/java/lang/Object.html#clone())() Creates and returns a copy of this `Object`. |\n| boolean | [equals](../../../reference/java/lang/Object.html#equals(java.lang.Object))([Object](../../../reference/java/lang/Object.html) obj) Compares this instance with the specified object and indicates if they are equal. |\n| void | [finalize](../../../reference/java/lang/Object.html#finalize())() Invoked when the garbage collector has detected that this instance is no longer reachable. |\n| final [Class](../../../reference/java/lang/Class.html)\\\u003c?\\\u003e | [getClass](../../../reference/java/lang/Object.html#getClass())() Returns the unique instance of [Class](../../../reference/java/lang/Class.html) that represents this object's class. |\n| int | [hashCode](../../../reference/java/lang/Object.html#hashCode())() Returns an integer hash code for this object. |\n| final void | [notify](../../../reference/java/lang/Object.html#notify())() Causes a thread which is waiting on this object's monitor (by means of calling one of the `wait()` methods) to be woken up. |\n| final void | [notifyAll](../../../reference/java/lang/Object.html#notifyAll())() Causes all threads which are waiting on this object's monitor (by means of calling one of the `wait()` methods) to be woken up. |\n| [String](../../../reference/java/lang/String.html) | [toString](../../../reference/java/lang/Object.html#toString())() Returns a string containing a concise, human-readable description of this object. |\n| final void | [wait](../../../reference/java/lang/Object.html#wait(long,%20int))(long timeout, int nanos) Causes the calling thread to wait until another thread calls the `notify()` or `notifyAll()` method of this object or until the specified timeout expires. |\n| final void | [wait](../../../reference/java/lang/Object.html#wait(long))(long timeout) Causes the calling thread to wait until another thread calls the `notify()` or `notifyAll()` method of this object or until the specified timeout expires. |\n| final void | [wait](../../../reference/java/lang/Object.html#wait())() Causes the calling thread to wait until another thread calls the `notify()` or `notifyAll()` method of this object. |\n\nPublic Constructors\n-------------------\n\n#### public\n**URLDecoder**\n()\n\n\u003cbr /\u003e\n\nPublic Methods\n--------------\n\n#### public static [String](../../../reference/java/lang/String.html)\n**decode**\n([String](../../../reference/java/lang/String.html) s)\n\n\n**This method is deprecated.** \nThe resulting string may vary depending on the platform's\ndefault encoding. Instead, use the decode(String,String) method\nto specify the encoding. \nDecodes a `x-www-form-urlencoded` string.\nThe platform's default encoding is used to determine what characters\nare represented by any consecutive sequences of the form\n\"*`%xy`*\". \n\n##### Parameters\n\n| s | the `String` to decode |\n|---|------------------------|\n\n##### Returns\n\n- the newly decoded `String` \n\n#### public static [String](../../../reference/java/lang/String.html)\n**decode**\n([String](../../../reference/java/lang/String.html) s, [String](../../../reference/java/lang/String.html) enc)\n\nDecodes a `application/x-www-form-urlencoded` string using a specific\nencoding scheme.\nThe supplied encoding is used to determine\nwhat characters are represented by any consecutive sequences of the\nform \"*`%xy`*\".\n\n\n***Note:** The [World Wide Web Consortium Recommendation](http://www.w3.org/TR/html40/appendix/notes.html#non-ascii-chars) states that\nUTF-8 should be used. Not doing so may introduce\nincompatibilities.* \n\n##### Parameters\n\n| s | the `String` to decode |\n| enc | The name of a supported [character encoding](../lang/package-summary.html#charenc). |\n|-----|-------------------------------------------------------------------------------------|\n\n##### Returns\n\n- the newly decoded `String` \n\n##### Throws\n\n| [UnsupportedEncodingException](../../../reference/java/io/UnsupportedEncodingException.html) | If character encoding needs to be consulted, but named character encoding is not supported |\n|----------------------------------------------------------------------------------------------|--------------------------------------------------------------------------------------------|\n\n##### See Also\n\n- [URLEncoder.encode(java.lang.String, java.lang.String)](../../../reference/java/net/URLEncoder.html#encode(java.lang.String,%20java.lang.String))"]]