OpenJDK 24 · java.net.URLDecoder · APIdia, the JavaDoc alternative

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 charset 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 java.lang.IllegalArgumentException. Which approach the decoder takes is left to the implementation.

Access	Constructor and Description
private	URLDecoder() Do not call.

Method Summary

Modifier and Type	Method and Description
public static String	Returns: the newly decoded `String` decode(String the `String` to decode s) Deprecated The resulting string may vary depending on the default charset. Instead, use the decode(String,String) method to specify the encoding. Decodes a `x-www-form-urlencoded` string.
public static String	Returns: the newly decoded `String` decode(String the `String` to decode s, String The name of a supported character encoding. enc) Decodes an `application/x-www-form-urlencoded` string using a specific encoding scheme.
public static String	Returns: the newly decoded `String` decode(String the `String` to decode s, Charset the given charset charset) Decodes an `application/x-www-form-urlencoded` string using a specific Charset.

Inherited from java.lang.Object:: clone equals finalize getClass hashCode notify notifyAll toString wait wait wait

Constructor Detail

URLDecoder	back to summary
private URLDecoder() Do not call.

Method Detail

decode back to summary

decode	back to summary
public static String decode(String s) Deprecated The resulting string may vary depending on the default charset. Instead, use the decode(String,String) method to specify the encoding. Decodes a `x-www-form-urlencoded` string. The default charset is used to determine what characters are represented by any consecutive sequences of the form "`%xy`". Parameters s:String the `String` to decode Returns:String the newly decoded `String` Annotations @Deprecated Exceptions IllegalArgumentException: if the implementation encounters malformed escape sequences

public static String decode(String s)

Deprecated

The resulting string may vary depending on the default charset. Instead, use the decode(String,String) method to specify the encoding.

Decodes a x-www-form-urlencoded string. The default charset is used to determine what characters are represented by any consecutive sequences of the form "%xy".

Parameters

s:String: the String to decode

Returns:String

the newly decoded String

Annotations

@Deprecated

Exceptions

IllegalArgumentException:: if the implementation encounters malformed escape sequences

decode back to summary

decode	back to summary
public static String decode(String s, String enc) throws UnsupportedEncodingException Decodes an `application/x-www-form-urlencoded` string using a specific encoding scheme. This method behaves the same as decode(String s, Charset charset) except that it will look up the charset using the given encoding name. Parameters s:String the `String` to decode enc:String The name of a supported character encoding. Returns:String the newly decoded `String` Exceptions UnsupportedEncodingException: If character encoding needs to be consulted, but named character encoding is not supported IllegalArgumentException: if the implementation encounters malformed escape sequences Since 1.4 See Also `URLEncoder#encode(java.lang.String, java.lang.String)`

public static String decode(String s, String enc) throws UnsupportedEncodingException

Decodes an application/x-www-form-urlencoded string using a specific encoding scheme.

This method behaves the same as decode(String s, Charset charset) except that it will look up the charset using the given encoding name.

Parameters

s:String: the String to decode
enc:String: The name of a supported character encoding.

Returns:String

the newly decoded String

Exceptions

UnsupportedEncodingException:: If character encoding needs to be consulted, but named character encoding is not supported
IllegalArgumentException:: if the implementation encounters malformed escape sequences

Since

1.4

decode back to summary

decode	back to summary
public static String decode(String s, Charset charset) Decodes an `application/x-www-form-urlencoded` string using a specific Charset. The supplied charset is used to determine what characters are represented by any consecutive escape sequences of the form "`%xy`". Erroneous bytes are replaced with the supplied `Charset`'s replacement value. Note The World Wide Web Consortium Recommendation states that UTF-8 should be used. Not doing so may introduce incompatibilities. Parameters s:String the `String` to decode charset:Charset the given charset Returns:String the newly decoded `String` Exceptions NullPointerException: if `s` or `charset` is `null` IllegalArgumentException: if the implementation encounters malformed escape sequences Since 10 External Specification https://www.w3.org/TR/html4 See Also `URLEncoder#encode(java.lang.String, Charset)`

public static String decode(String s, Charset charset)

Decodes an application/x-www-form-urlencoded string using a specific Charset. The supplied charset is used to determine what characters are represented by any consecutive escape sequences of the form "%xy". Erroneous bytes are replaced with the supplied Charset's replacement value.

Note

The World Wide Web Consortium Recommendation states that UTF-8 should be used. Not doing so may introduce incompatibilities.

Parameters

s:String: the String to decode
charset:Charset: the given charset

Returns:String

the newly decoded String

Exceptions

NullPointerException:: if s or charset is null
IllegalArgumentException:: if the implementation encounters malformed escape sequences

Since

External Specification

https://www.w3.org/TR/html4

public Class URLDecoder

Constructor Summary

Method Summary

Constructor Detail

Method Detail