Class URLEncoder

java.lang.Object

java.net.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 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

• HTML 4.01 Specification

See Also:

• Charset.defaultCharset()

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 java.lang.Object

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

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:

• 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.

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:

10

External Specifications

• HTML 4.01 Specification

See Also:

• URLDecoder.decode(java.lang.String, Charset)