Class URLEncoder

java.lang.Object

java.net.URLEncoder

public final class URLEncoder extends Object

Utility class for HTML form encoding. This class contains static methods for converting a String to the application/x-www-form-urlencoded MIME format. For more information about HTML form encoding, consult the HTML specification.

When encoding a String, the following rules apply:

The alphanumeric characters "a" through "z", "A" through "Z" and "0" through "9" remain the same.
The special characters ".", "-", "*", and "_" remain the same.
The space character " " is converted into a plus sign "+".
All other characters are unsafe and are first converted into one or more bytes using some encoding scheme. Then each byte is represented by the 3-character string "%xy", where xy is the two-digit hexadecimal representation of the byte. The recommended encoding scheme to use is UTF-8. However, for compatibility reasons, if an encoding is not specified, then the default charset is used.

For example using UTF-8 as the encoding scheme the string "The string ü@foo-bar" would get converted to "The+string+%C3%BC%40foo-bar" because in UTF-8 the character ü is encoded as two bytes C3 (hex) and BC (hex), and the character @ is encoded as one byte 40 (hex).

Since:

1.0

External Specifications

See Also:

Method Summary

Modifier and Type	Method	Description
`static String`	`encode(String s)`	Deprecated. The resulting string may vary depending on the default charset.
`static String`	`encode(String s, String enc)`	Translates a string into `application/x-www-form-urlencoded` format using a specific encoding scheme.
`static String`	`encode(String s, Charset charset)`	Translates a string into `application/x-www-form-urlencoded` format using a specific Charset.

Methods declared in class Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Modifier and Type	Method	Description
`protected Object`	`clone()`	Creates and returns a copy of this object.
`boolean`	`equals(Object obj)`	Indicates whether some other object is "equal to" this one.
`protected void`	`finalize()`	Deprecated, for removal: This API element is subject to removal in a future version. Finalization is deprecated and subject to removal in a future release.
`final Class<?>`	`getClass()`	Returns the runtime class of this `Object`.
`int`	`hashCode()`	Returns a hash code value for this object.
`final void`	`notify()`	Wakes up a single thread that is waiting on this object's monitor.
`final void`	`notifyAll()`	Wakes up all threads that are waiting on this object's monitor.
`String`	`toString()`	Returns a string representation of the object.
`final void`	`wait()`	Causes the current thread to wait until it is awakened, typically by being notified or interrupted.
`final void`	`wait(long timeoutMillis)`	Causes the current thread to wait until it is awakened, typically by being notified or interrupted, or until a certain amount of real time has elapsed.
`final void`	`wait(long timeoutMillis, int nanos)`	Causes the current thread to wait until it is awakened, typically by being notified or interrupted, or until a certain amount of real time has elapsed.

Method Details

encode

@Deprecated public static String encode(String s)

Deprecated.

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

Translates a string into x-www-form-urlencoded format. This method uses the default charset as the encoding scheme to obtain the bytes for unsafe characters.

Parameters:: s - String to be translated.
Returns:: the translated String.

encode

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

Translates a string into application/x-www-form-urlencoded format using a specific encoding scheme.

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

Parameters:

s - String to be translated.

enc - The name of a supported character encoding.

Returns:

the translated String.

Throws:

UnsupportedEncodingException - If the named encoding is not supported

Since:

1.4

See Also:

encode

public static String encode(String s, Charset charset)

Translates a string into application/x-www-form-urlencoded format using a specific Charset. This method uses the supplied charset to obtain the bytes for unsafe characters.

If the input string is malformed, or if the input cannot be mapped to a valid byte sequence in the given Charset, then the erroneous input will be replaced with the Charset's replacement values.

API Note:

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

Parameters:

s - String to be translated.

charset - the given charset

Returns:

the translated String.

Throws:

NullPointerException - if s or charset is null.

Since:

External Specifications

See Also:

© 1993, 2025, Oracle and/or its affiliates. All rights reserved.
Documentation extracted from Debian's OpenJDK Development Kit package.
Licensed under the GNU General Public License, version 2, with the Classpath Exception.
Various third party code in OpenJDK is licensed under different licenses (see Debian package).
Java and OpenJDK are trademarks or registered trademarks of Oracle and/or its affiliates.