URLDecoder (Java SE 11 & JDK 11 )

java.lang.Object
- java.net.URLDecoder

```
public class URLDecoder
extends Object
```
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.
Since:

1.2

Constructor Summary

Constructors
Constructor Description

URLDecoder()

Constructors
Constructor	Description
`URLDecoder()`

Method Summary

All Methods Static Methods Concrete Methods Deprecated Methods
Modifier and Type	Method	Description
`static String`	`decode(String s)`	Deprecated. The resulting string may vary depending on the platform's default encoding.
`static String`	`decode(String s, String enc)`	Decodes an `application/x-www-form-urlencoded` string using a specific encoding scheme.
`static String`	`decode(String s, Charset charset)`	Decodes an `application/x-www-form-urlencoded` string using a specific Charset.

Methods declared in class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

- Constructor Detail
  - URLDecoder
```
public URLDecoder()
```
- Method Detail
  - decode
```
@Deprecated
public static String decode(String s)
```
    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".
    
    Parameters:
    
    s - the String to decode
    
    Returns:
    
    the newly decoded String
  - decode
```
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(java.lang.String,java.nio.charset.Charset) except that it will look up the charset using the given encoding name.
    
    Implementation Note:
    
    This implementation will throw an IllegalArgumentException when illegal strings are encountered.
    
    Parameters:
    
    s - the String to decode
    
    enc - The name of a supported character encoding.
    
    Returns:
    
    the newly decoded String
    
    Throws:
    
    UnsupportedEncodingException - If character encoding needs to be consulted, but named character encoding is not supported
    
    Since:
    
    1.4
    
    See Also:
    
    URLEncoder.encode(java.lang.String, java.lang.String)
  - decode
```
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 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.
    
    Implementation Note:
    
    This implementation will throw an IllegalArgumentException when illegal strings are encountered.
    
    Parameters:
    
    s - the String to decode
    
    charset - the given charset
    
    Returns:
    
    the newly decoded String
    
    Throws:
    
    NullPointerException - if s or charset is null
    
    IllegalArgumentException - if the implementation encounters illegal characters
    
    Since:
    
    10
    
    See Also:
    
    URLEncoder.encode(java.lang.String, java.nio.charset.Charset)

Constructor Summary

Method Summary

Methods declared in class java.lang.Object

Constructor Detail

URLDecoder

Method Detail

decode

decode

decode