Added in [API level 1](https://developer.android.com/guide/topics/manifest/uses-sdk-element#ApiLevels) Summary: [Ctors](https://developer.android.com/reference/java/net/URLDecoder#pubctors) \| [Methods](https://developer.android.com/reference/java/net/URLDecoder#pubmethods) \| [Inherited Methods](https://developer.android.com/reference/java/net/URLDecoder#inhmethods)

# URLDecoder


`
public


class
URLDecoder
`


`

extends https://developer.android.com/reference/java/lang/Object


`

`


`

|---|---|
| [java.lang.Object](https://developer.android.com/reference/java/lang/Object) ||
| ↳ | java.net.URLDecoder |

<br />

*** ** * ** ***

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 `https://developer.android.com/reference/java/lang/IllegalArgumentException`.
Which approach the decoder takes is left to the
implementation.

## Summary

| ### Public constructors ||
|---|---|
| ` https://developer.android.com/reference/java/net/URLDecoder#URLDecoder()() ` |

| ### Public methods ||
|---|---|
| ` static https://developer.android.com/reference/java/lang/String` | ` https://developer.android.com/reference/java/net/URLDecoder#decode(java.lang.String)(https://developer.android.com/reference/java/lang/String s) ` *This method was deprecated in API level 15. The resulting string may vary depending on the platform's default encoding. Instead, use the decode(String,String) method to specify the encoding.* |
| ` static https://developer.android.com/reference/java/lang/String` | ` https://developer.android.com/reference/java/net/URLDecoder#decode(java.lang.String,%20java.nio.charset.Charset)(https://developer.android.com/reference/java/lang/String s, https://developer.android.com/reference/java/nio/charset/Charset charset) ` Decodes an `application/x-www-form-urlencoded` string using a specific [Charset](https://developer.android.com/reference/java/nio/charset/Charset). |
| ` static https://developer.android.com/reference/java/lang/String` | ` https://developer.android.com/reference/java/net/URLDecoder#decode(java.lang.String,%20java.lang.String)(https://developer.android.com/reference/java/lang/String s, https://developer.android.com/reference/java/lang/String enc) ` Decodes an `application/x-www-form-urlencoded` string using a specific encoding scheme. |

| ### Inherited methods |
|---|---|
| From class ` https://developer.android.com/reference/java/lang/Object ` |---|---| | ` https://developer.android.com/reference/java/lang/Object` | ` https://developer.android.com/reference/java/lang/Object#clone()() ` Creates and returns a copy of this object. | | ` boolean` | ` https://developer.android.com/reference/java/lang/Object#equals(java.lang.Object)(https://developer.android.com/reference/java/lang/Object obj) ` Indicates whether some other object is "equal to" this one. | | ` void` | ` https://developer.android.com/reference/java/lang/Object#finalize()() ` Called by the garbage collector on an object when garbage collection determines that there are no more references to the object. | | ` final https://developer.android.com/reference/java/lang/Class<?>` | ` https://developer.android.com/reference/java/lang/Object#getClass()() ` Returns the runtime class of this `Object`. | | ` int` | ` https://developer.android.com/reference/java/lang/Object#hashCode()() ` Returns a hash code value for the object. | | ` final void` | ` https://developer.android.com/reference/java/lang/Object#notify()() ` Wakes up a single thread that is waiting on this object's monitor. | | ` final void` | ` https://developer.android.com/reference/java/lang/Object#notifyAll()() ` Wakes up all threads that are waiting on this object's monitor. | | ` https://developer.android.com/reference/java/lang/String` | ` https://developer.android.com/reference/java/lang/Object#toString()() ` Returns a string representation of the object. | | ` final void` | ` https://developer.android.com/reference/java/lang/Object#wait(long,%20int)(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. | | ` final void` | ` https://developer.android.com/reference/java/lang/Object#wait(long)(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` | ` https://developer.android.com/reference/java/lang/Object#wait()() ` Causes the current thread to wait until it is awakened, typically by being *notified* or *interrupted*. | ||

## Public constructors

### URLDecoder

Added in [API level 1](https://developer.android.com/guide/topics/manifest/uses-sdk-element#ApiLevels)

```
public URLDecoder ()
```

<br />

<br />

## Public methods

### decode

Added in [API level 1](https://developer.android.com/guide/topics/manifest/uses-sdk-element#ApiLevels)   
Deprecated in [API level
15](https://developer.android.com/guide/topics/manifest/uses-sdk-element#ApiLevels)

```
public static String decode (String s)
```


**This method was deprecated
in API level 15.**   

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

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`*".

<br />

| Parameters ||
|---|---|
| `s` | `String`: the `String` to decode <br /> |

| Returns ||
|---|---|
| `https://developer.android.com/reference/java/lang/String` | the newly decoded `String` <br /> |

### decode

Added in [API level 33](https://developer.android.com/guide/topics/manifest/uses-sdk-element#ApiLevels)

```
public static String decode (String s, 
                Charset charset)
```

Decodes an `application/x-www-form-urlencoded` string using
a specific [Charset](https://developer.android.com/reference/java/nio/charset/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](http://www.w3.org/TR/html40/appendix/notes.html#non-ascii-chars) states that
UTF-8 should be used. Not doing so may introduce
incompatibilities.*

<br />

##### Implementation Note:

- This implementation will throw an `https://developer.android.com/reference/java/lang/IllegalArgumentException` when illegal strings are encountered.

| Parameters ||
|---|---|
| `s` | `String`: the `String` to decode <br /> |
| `charset` | `Charset`: the given charset <br /> |

| Returns ||
|---|---|
| `https://developer.android.com/reference/java/lang/String` | the newly decoded `String` <br /> |

| Throws ||
|---|---|
| `https://developer.android.com/reference/java/lang/IllegalArgumentException` | if the implementation encounters illegal characters |
| `https://developer.android.com/reference/java/lang/NullPointerException` | if `s` or `charset` is `null` |

**See also:**

- `https://developer.android.com/reference/java/net/URLEncoder#encode(java.lang.String,%20java.nio.charset.Charset)`

### decode

Added in [API level 1](https://developer.android.com/guide/topics/manifest/uses-sdk-element#ApiLevels)

```
public static String decode (String s, 
                String enc)
```

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


This method behaves the same as [decode(String s, Charset charset)](https://developer.android.com/reference/java/lang/String)
except that it will [look up the charset](https://developer.android.com/reference/java/nio/charset/Charset#forName(java.lang.String))
using the given encoding name.

<br />

##### Implementation Note:

- This implementation will throw an `https://developer.android.com/reference/java/lang/IllegalArgumentException` when illegal strings are encountered.

| Parameters ||
|---|---|
| `s` | `String`: the `String` to decode <br /> |
| `enc` | `String`: The name of a supported [character encoding](https://developer.android.com/reference/java/lang/package-summary.html#charenc). <br /> |

| Returns ||
|---|---|
| `https://developer.android.com/reference/java/lang/String` | the newly decoded `String` <br /> |

| Throws ||
|---|---|
| `https://developer.android.com/reference/java/io/UnsupportedEncodingException` | If character encoding needs to be consulted, but named character encoding is not supported |

**See also:**

- `https://developer.android.com/reference/java/net/URLEncoder#encode(java.lang.String,%20java.lang.String)`