Android APIs
public class

JSONObject

extends Object
java.lang.Object
   ↳ org.json.JSONObject

Class Overview

A modifiable set of name/value mappings. Names are unique, non-null strings. Values may be any mix of JSONObjects, JSONArrays, Strings, Booleans, Integers, Longs, Doubles or NULL. Values may not be null, NaNs, infinities, or of any type not listed here.

This class can coerce values to another type when requested.

  • When the requested type is a boolean, strings will be coerced using a case-insensitive comparison to "true" and "false".
  • When the requested type is a double, other Number types will be coerced using doubleValue. Strings that can be coerced using valueOf(String) will be.
  • When the requested type is an int, other Number types will be coerced using intValue. Strings that can be coerced using valueOf(String) will be, and then cast to int.
  • When the requested type is a long, other Number types will be coerced using longValue. Strings that can be coerced using valueOf(String) will be, and then cast to long. This two-step conversion is lossy for very large values. For example, the string "9223372036854775806" yields the long 9223372036854775807.
  • When the requested type is a String, other non-null values will be coerced using valueOf(Object). Although null cannot be coerced, the sentinel value NULL is coerced to the string "null".

This class can look up both mandatory and optional values:

  • Use getType() to retrieve a mandatory value. This fails with a JSONException if the requested name has no value or if the value cannot be coerced to the requested type.
  • Use optType() to retrieve an optional value. This returns a system- or user-supplied default if the requested name has no value or if the value cannot be coerced to the requested type.

Warning: this class represents null in two incompatible ways: the standard Java null reference, and the sentinel value NULL. In particular, calling put(name, null) removes the named entry from the object but put(name, JSONObject.NULL) stores an entry whose value is JSONObject.NULL.

Instances of this class are not thread safe. Although this class is nonfinal, it was not designed for inheritance and should not be subclassed. In particular, self-use by overrideable methods is not specified. See Effective Java Item 17, "Design and Document or inheritance or else prohibit it" for further information.

Summary

Fields
public static final Object NULL A sentinel value used to explicitly define a name with no value.
Public Constructors
JSONObject()
Creates a JSONObject with no name/value mappings.
JSONObject(Map copyFrom)
Creates a new JSONObject by copying all name/value mappings from the given map.
JSONObject(JSONTokener readFrom)
Creates a new JSONObject with name/value mappings from the next object in the tokener.
JSONObject(String json)
Creates a new JSONObject with name/value mappings from the JSON string.
JSONObject(JSONObject copyFrom, String[] names)
Creates a new JSONObject by copying mappings for the listed names from the given object.
Public Methods
JSONObject accumulate(String name, Object value)
Appends value to the array already mapped to name.
Object get(String name)
Returns the value mapped by name, or throws if no such mapping exists.
boolean getBoolean(String name)
Returns the value mapped by name if it exists and is a boolean or can be coerced to a boolean, or throws otherwise.
double getDouble(String name)
Returns the value mapped by name if it exists and is a double or can be coerced to a double, or throws otherwise.
int getInt(String name)
Returns the value mapped by name if it exists and is an int or can be coerced to an int, or throws otherwise.
JSONArray getJSONArray(String name)
Returns the value mapped by name if it exists and is a JSONArray, or throws otherwise.
JSONObject getJSONObject(String name)
Returns the value mapped by name if it exists and is a JSONObject, or throws otherwise.
long getLong(String name)
Returns the value mapped by name if it exists and is a long or can be coerced to a long, or throws otherwise.
String getString(String name)
Returns the value mapped by name if it exists, coercing it if necessary, or throws if no such mapping exists.
boolean has(String name)
Returns true if this object has a mapping for name.
boolean isNull(String name)
Returns true if this object has no mapping for name or if it has a mapping whose value is NULL.
Iterator<String> keys()
Returns an iterator of the String names in this object.
int length()
Returns the number of name/value mappings in this object.
JSONArray names()
Returns an array containing the string names in this object.
static String numberToString(Number number)
Encodes the number as a JSON string.
Object opt(String name)
Returns the value mapped by name, or null if no such mapping exists.
boolean optBoolean(String name)
Returns the value mapped by name if it exists and is a boolean or can be coerced to a boolean, or false otherwise.
boolean optBoolean(String name, boolean fallback)
Returns the value mapped by name if it exists and is a boolean or can be coerced to a boolean, or fallback otherwise.
double optDouble(String name, double fallback)
Returns the value mapped by name if it exists and is a double or can be coerced to a double, or fallback otherwise.
double optDouble(String name)
Returns the value mapped by name if it exists and is a double or can be coerced to a double, or NaN otherwise.
int optInt(String name, int fallback)
Returns the value mapped by name if it exists and is an int or can be coerced to an int, or fallback otherwise.
int optInt(String name)
Returns the value mapped by name if it exists and is an int or can be coerced to an int, or 0 otherwise.
JSONArray optJSONArray(String name)
Returns the value mapped by name if it exists and is a JSONArray, or null otherwise.
JSONObject optJSONObject(String name)
Returns the value mapped by name if it exists and is a JSONObject, or null otherwise.
long optLong(String name)
Returns the value mapped by name if it exists and is a long or can be coerced to a long, or 0 otherwise.
long optLong(String name, long fallback)
Returns the value mapped by name if it exists and is a long or can be coerced to a long, or fallback otherwise.
String optString(String name)
Returns the value mapped by name if it exists, coercing it if necessary, or the empty string if no such mapping exists.
String optString(String name, String fallback)
Returns the value mapped by name if it exists, coercing it if necessary, or fallback if no such mapping exists.
JSONObject put(String name, int value)
Maps name to value, clobbering any existing name/value mapping with the same name.
JSONObject put(String name, long value)
Maps name to value, clobbering any existing name/value mapping with the same name.
JSONObject put(String name, Object value)
Maps name to value, clobbering any existing name/value mapping with the same name.
JSONObject put(String name, boolean value)
Maps name to value, clobbering any existing name/value mapping with the same name.
JSONObject put(String name, double value)
Maps name to value, clobbering any existing name/value mapping with the same name.
JSONObject putOpt(String name, Object value)
Equivalent to put(name, value) when both parameters are non-null; does nothing otherwise.
static String quote(String data)
Encodes data as a JSON string.
Object remove(String name)
Removes the named mapping if it exists; does nothing otherwise.
JSONArray toJSONArray(JSONArray names)
Returns an array with the values corresponding to names.
String toString()
Encodes this object as a compact JSON string, such as:
{"query":"Pizza","locations":[94043,90210]}
String toString(int indentSpaces)
Encodes this object as a human readable JSON string for debugging, such as:
 {
     "query": "Pizza",
     "locations": [
         94043,
         90210
     ]
 }
static Object wrap(Object o)
Wraps the given object if necessary.
[Expand]
Inherited Methods
From class java.lang.Object

Fields

public static final Object NULL

Added in API level 1

A sentinel value used to explicitly define a name with no value. Unlike null, names with this value:

This value violates the general contract of equals(Object) by returning true when compared to null. Its toString() method returns "null".

Public Constructors

public JSONObject ()

Added in API level 1

Creates a JSONObject with no name/value mappings.

public JSONObject (Map copyFrom)

Added in API level 1

Creates a new JSONObject by copying all name/value mappings from the given map.

Parameters
copyFrom Map: a map whose keys are of type String and whose values are of supported types.
Throws
NullPointerException if any of the map's keys are null.

public JSONObject (JSONTokener readFrom)

Added in API level 1

Creates a new JSONObject with name/value mappings from the next object in the tokener.

Parameters
readFrom JSONTokener: a tokener whose nextValue() method will yield a JSONObject.
Throws
JSONException if the parse fails or doesn't yield a JSONObject.

public JSONObject (String json)

Added in API level 1

Creates a new JSONObject with name/value mappings from the JSON string.

Parameters
json String: a JSON-encoded string containing an object.
Throws
JSONException if the parse fails or doesn't yield a JSONObject.

public JSONObject (JSONObject copyFrom, String[] names)

Added in API level 1

Creates a new JSONObject by copying mappings for the listed names from the given object. Names that aren't present in copyFrom will be skipped.

Parameters
copyFrom JSONObject
names String
Throws
JSONException

Public Methods

public JSONObject accumulate (String name, Object value)

Added in API level 1

Appends value to the array already mapped to name. If this object has no mapping for name, this inserts a new mapping. If the mapping exists but its value is not an array, the existing and new values are inserted in order into a new array which is itself mapped to name. In aggregate, this allows values to be added to a mapping one at a time.

Note that append(String, Object) provides better semantics. In particular, the mapping for name will always be a JSONArray. Using accumulate will result in either a JSONArray or a mapping whose type is the type of value depending on the number of calls to it.

Parameters
name String
value Object: a JSONObject, JSONArray, String, Boolean, Integer, Long, Double, NULL or null. May not be NaNs or infinities.
Returns
JSONObject
Throws
JSONException

public Object get (String name)

Added in API level 1

Returns the value mapped by name, or throws if no such mapping exists.

Parameters
name String
Returns
Object
Throws
JSONException if no such mapping exists.

public boolean getBoolean (String name)

Added in API level 1

Returns the value mapped by name if it exists and is a boolean or can be coerced to a boolean, or throws otherwise.

Parameters
name String
Returns
boolean
Throws
JSONException if the mapping doesn't exist or cannot be coerced to a boolean.

public double getDouble (String name)

Added in API level 1

Returns the value mapped by name if it exists and is a double or can be coerced to a double, or throws otherwise.

Parameters
name String
Returns
double
Throws
JSONException if the mapping doesn't exist or cannot be coerced to a double.

public int getInt (String name)

Added in API level 1

Returns the value mapped by name if it exists and is an int or can be coerced to an int, or throws otherwise.

Parameters
name String
Returns
int
Throws
JSONException if the mapping doesn't exist or cannot be coerced to an int.

public JSONArray getJSONArray (String name)

Added in API level 1

Returns the value mapped by name if it exists and is a JSONArray, or throws otherwise.

Parameters
name String
Returns
JSONArray
Throws
JSONException if the mapping doesn't exist or is not a JSONArray.

public JSONObject getJSONObject (String name)

Added in API level 1

Returns the value mapped by name if it exists and is a JSONObject, or throws otherwise.

Parameters
name String
Returns
JSONObject
Throws
JSONException if the mapping doesn't exist or is not a JSONObject.

public long getLong (String name)

Added in API level 1

Returns the value mapped by name if it exists and is a long or can be coerced to a long, or throws otherwise. Note that JSON represents numbers as doubles, so this is lossy; use strings to transfer numbers via JSON.

Parameters
name String
Returns
long
Throws
JSONException if the mapping doesn't exist or cannot be coerced to a long.

public String getString (String name)

Added in API level 1

Returns the value mapped by name if it exists, coercing it if necessary, or throws if no such mapping exists.

Parameters
name String
Returns
String
Throws
JSONException if no such mapping exists.

public boolean has (String name)

Added in API level 1

Returns true if this object has a mapping for name. The mapping may be NULL.

Parameters
name String
Returns
boolean

public boolean isNull (String name)

Added in API level 1

Returns true if this object has no mapping for name or if it has a mapping whose value is NULL.

Parameters
name String
Returns
boolean

public Iterator<String> keys ()

Added in API level 1

Returns an iterator of the String names in this object. The returned iterator supports remove, which will remove the corresponding mapping from this object. If this object is modified after the iterator is returned, the iterator's behavior is undefined. The order of the keys is undefined.

Returns
Iterator<String>

public int length ()

Added in API level 1

Returns the number of name/value mappings in this object.

Returns
int

public JSONArray names ()

Added in API level 1

Returns an array containing the string names in this object. This method returns null if this object contains no mappings.

Returns
JSONArray

public static String numberToString (Number number)

Added in API level 1

Encodes the number as a JSON string.

Parameters
number Number: a finite value. May not be NaNs or infinities.
Returns
String
Throws
JSONException

public Object opt (String name)

Added in API level 1

Returns the value mapped by name, or null if no such mapping exists.

Parameters
name String
Returns
Object

public boolean optBoolean (String name)

Added in API level 1

Returns the value mapped by name if it exists and is a boolean or can be coerced to a boolean, or false otherwise.

Parameters
name String
Returns
boolean

public boolean optBoolean (String name, boolean fallback)

Added in API level 1

Returns the value mapped by name if it exists and is a boolean or can be coerced to a boolean, or fallback otherwise.

Parameters
name String
fallback boolean
Returns
boolean

public double optDouble (String name, double fallback)

Added in API level 1

Returns the value mapped by name if it exists and is a double or can be coerced to a double, or fallback otherwise.

Parameters
name String
fallback double
Returns
double

public double optDouble (String name)

Added in API level 1

Returns the value mapped by name if it exists and is a double or can be coerced to a double, or NaN otherwise.

Parameters
name String
Returns
double

public int optInt (String name, int fallback)

Added in API level 1

Returns the value mapped by name if it exists and is an int or can be coerced to an int, or fallback otherwise.

Parameters
name String
fallback int
Returns
int

public int optInt (String name)

Added in API level 1

Returns the value mapped by name if it exists and is an int or can be coerced to an int, or 0 otherwise.

Parameters
name String
Returns
int

public JSONArray optJSONArray (String name)

Added in API level 1

Returns the value mapped by name if it exists and is a JSONArray, or null otherwise.

Parameters
name String
Returns
JSONArray

public JSONObject optJSONObject (String name)

Added in API level 1

Returns the value mapped by name if it exists and is a JSONObject, or null otherwise.

Parameters
name String
Returns
JSONObject

public long optLong (String name)

Added in API level 1

Returns the value mapped by name if it exists and is a long or can be coerced to a long, or 0 otherwise. Note that JSON represents numbers as doubles, so this is lossy; use strings to transfer numbers via JSON.

Parameters
name String
Returns
long

public long optLong (String name, long fallback)

Added in API level 1

Returns the value mapped by name if it exists and is a long or can be coerced to a long, or fallback otherwise. Note that JSON represents numbers as doubles, so this is lossy; use strings to transfer numbers via JSON.

Parameters
name String
fallback long
Returns
long

public String optString (String name)

Added in API level 1

Returns the value mapped by name if it exists, coercing it if necessary, or the empty string if no such mapping exists.

Parameters
name String
Returns
String

public String optString (String name, String fallback)

Added in API level 1

Returns the value mapped by name if it exists, coercing it if necessary, or fallback if no such mapping exists.

Parameters
name String
fallback String
Returns
String

public JSONObject put (String name, int value)

Added in API level 1

Maps name to value, clobbering any existing name/value mapping with the same name.

Parameters
name String
value int
Returns
JSONObject this object.
Throws
JSONException

public JSONObject put (String name, long value)

Added in API level 1

Maps name to value, clobbering any existing name/value mapping with the same name.

Parameters
name String
value long
Returns
JSONObject this object.
Throws
JSONException

public JSONObject put (String name, Object value)

Added in API level 1

Maps name to value, clobbering any existing name/value mapping with the same name. If the value is null, any existing mapping for name is removed.

Parameters
name String
value Object: a JSONObject, JSONArray, String, Boolean, Integer, Long, Double, NULL, or null. May not be NaNs or infinities.
Returns
JSONObject this object.
Throws
JSONException

public JSONObject put (String name, boolean value)

Added in API level 1

Maps name to value, clobbering any existing name/value mapping with the same name.

Parameters
name String
value boolean
Returns
JSONObject this object.
Throws
JSONException

public JSONObject put (String name, double value)

Added in API level 1

Maps name to value, clobbering any existing name/value mapping with the same name.

Parameters
name String
value double: a finite value. May not be NaNs or infinities.
Returns
JSONObject this object.
Throws
JSONException

public JSONObject putOpt (String name, Object value)

Added in API level 1

Equivalent to put(name, value) when both parameters are non-null; does nothing otherwise.

Parameters
name String
value Object
Returns
JSONObject
Throws
JSONException

public static String quote (String data)

Added in API level 1

Encodes data as a JSON string. This applies quotes and any necessary character escaping.

Parameters
data String: the string to encode. Null will be interpreted as an empty string.
Returns
String

public Object remove (String name)

Added in API level 1

Removes the named mapping if it exists; does nothing otherwise.

Parameters
name String
Returns
Object the value previously mapped by name, or null if there was no such mapping.

public JSONArray toJSONArray (JSONArray names)

Added in API level 1

Returns an array with the values corresponding to names. The array contains null for names that aren't mapped. This method returns null if names is either null or empty.

Parameters
names JSONArray
Returns
JSONArray
Throws
JSONException

public String toString ()

Added in API level 1

Encodes this object as a compact JSON string, such as:

{"query":"Pizza","locations":[94043,90210]}

Returns
String a printable representation of this object.

public String toString (int indentSpaces)

Added in API level 1

Encodes this object as a human readable JSON string for debugging, such as:

 {
     "query": "Pizza",
     "locations": [
         94043,
         90210
     ]
 }

Parameters
indentSpaces int: the number of spaces to indent for each level of nesting.
Returns
String
Throws
JSONException

public static Object wrap (Object o)

Added in API level 19

Wraps the given object if necessary.

If the object is null or , returns NULL. If the object is a JSONArray or JSONObject, no wrapping is necessary. If the object is NULL, no wrapping is necessary. If the object is an array or Collection, returns an equivalent JSONArray. If the object is a Map, returns an equivalent JSONObject. If the object is a primitive wrapper type or String, returns the object. Otherwise if the object is from a java package, returns the result of toString. If wrapping fails, returns null.

Parameters
o Object
Returns
Object