Class URLEncoder

public 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 encoding of the platform 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

Method Summary

All Methods Static Methods Concrete Methods Deprecated Methods
Modifier and Type Method Description
static String encode​(String s)

Deprecated.

The resulting string may vary depending on the platform's default encoding.
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 java.lang.Object

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

Method Detail

encode

@Deprecated
public static String encode​(String s)
Deprecated.
The resulting string may vary depending on the platform's default encoding. Instead, use the encode(String,String) method to specify the encoding.

Translates a string into x-www-form-urlencoded format. This method uses the platform's default encoding 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(java.lang.String,java.nio.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:
URLDecoder.decode(java.lang.String, java.lang.String)

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.

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:
10
See Also:
URLDecoder.decode(java.lang.String, java.nio.charset.Charset)