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.
boolean getBoolean(String name)
Returns the value mapped by name if it exists and is a boolean or can be coerced to a boolean.
double getDouble(String name)
Returns the value mapped by name if it exists and is a double or can be coerced to a double.
int getInt(String name)
Returns the value mapped by name if it exists and is an int or can be coerced to an int.
JSONArray getJSONArray(String name)
Returns the value mapped by name if it exists and is a JSONArray.
JSONObject getJSONObject(String name)
Returns the value mapped by name if it exists and is a JSONObject.
long getLong(String name)
Returns the value mapped by name if it exists and is a long or can be coerced to a long.
String getString(String name)
Returns the value mapped by name if it exists, coercing it if necessary.
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 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.
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.
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.
double optDouble(String name)
Returns the value mapped by name if it exists and is a double or can be coerced to a double.
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.
int optInt(String name)
Returns the value mapped by name if it exists and is an int or can be coerced to an int.
JSONArray optJSONArray(String name)
Returns the value mapped by name if it exists and is a JSONArray.
JSONObject optJSONObject(String name)
Returns the value mapped by name if it exists and is a JSONObject.
long optLong(String name)
Returns the value mapped by name if it exists and is a long or can be coerced to a long.
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.
String optString(String name)
Returns the value mapped by name if it exists, coercing it if necessary.
String optString(String name, String fallback)
Returns the value mapped by name if it exists, coercing it if necessary.
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
     ]
 }
[Expand]
Inherited Methods
From class java.lang.Object

Fields

public static final Object NULL

Since: 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 ()

Since: API Level 1

Creates a JSONObject with no name/value mappings.

public JSONObject (Map copyFrom)

Since: API Level 1

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

Parameters
copyFrom 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)

Since: API Level 1

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

Parameters
readFrom 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)

Since: API Level 1

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

Parameters
json 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)

Since: 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.

Throws
JSONException

Public Methods

public JSONObject accumulate (String name, Object value)

Since: 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.

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

public Object get (String name)

Since: API Level 1

Returns the value mapped by name.

Throws
JSONException if no such mapping exists.

public boolean getBoolean (String name)

Since: API Level 1

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

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

public double getDouble (String name)

Since: API Level 1

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

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

public int getInt (String name)

Since: API Level 1

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

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

public JSONArray getJSONArray (String name)

Since: API Level 1

Returns the value mapped by name if it exists and is a JSONArray.

Throws
JSONException if the mapping doesn't exist or is not a JSONArray.

public JSONObject getJSONObject (String name)

Since: API Level 1

Returns the value mapped by name if it exists and is a JSONObject.

Throws
JSONException if the mapping doesn't exist or is not a JSONObject.

public long getLong (String name)

Since: API Level 1

Returns the value mapped by name if it exists and is a long or can be coerced to a long.

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

public String getString (String name)

Since: API Level 1

Returns the value mapped by name if it exists, coercing it if necessary.

Throws
JSONException if no such mapping exists.

public boolean has (String name)

Since: API Level 1

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

public boolean isNull (String name)

Since: API Level 1

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

public Iterator keys ()

Since: 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.

public int length ()

Since: API Level 1

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

public JSONArray names ()

Since: API Level 1

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

public static String numberToString (Number number)

Since: API Level 1

Encodes the number as a JSON string.

Parameters
number a finite value. May not be NaNs or infinities.
Throws
JSONException

public Object opt (String name)

Since: API Level 1

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

public boolean optBoolean (String name)

Since: API Level 1

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

public boolean optBoolean (String name, boolean fallback)

Since: API Level 1

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

public double optDouble (String name, double fallback)

Since: API Level 1

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

public double optDouble (String name)

Since: API Level 1

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

public int optInt (String name, int fallback)

Since: API Level 1

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

public int optInt (String name)

Since: API Level 1

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

public JSONArray optJSONArray (String name)

Since: API Level 1

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

public JSONObject optJSONObject (String name)

Since: API Level 1

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

public long optLong (String name)

Since: API Level 1

Returns the value mapped by name if it exists and is a long or can be coerced to a long. Returns 0 otherwise.

public long optLong (String name, long fallback)

Since: API Level 1

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

public String optString (String name)

Since: API Level 1

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

public String optString (String name, String fallback)

Since: API Level 1

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

public JSONObject put (String name, int value)

Since: API Level 1

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

Returns
  • this object.
Throws
JSONException

public JSONObject put (String name, long value)

Since: API Level 1

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

Returns
  • this object.
Throws
JSONException

public JSONObject put (String name, Object value)

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

public JSONObject put (String name, boolean value)

Since: API Level 1

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

Returns
  • this object.
Throws
JSONException

public JSONObject put (String name, double value)

Since: API Level 1

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

Parameters
value a finite value. May not be NaNs or infinities.
Returns
  • this object.
Throws
JSONException

public JSONObject putOpt (String name, Object value)

Since: API Level 1

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

Throws
JSONException

public static String quote (String data)

Since: API Level 1

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

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

public Object remove (String name)

Since: API Level 1

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

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

public JSONArray toJSONArray (JSONArray names)

Since: 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.

Throws
JSONException

public String toString ()

Since: API Level 1

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

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

Returns
  • a printable representation of this object.

public String toString (int indentSpaces)

Since: API Level 1

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

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

Parameters
indentSpaces the number of spaces to indent for each level of nesting.
Throws
JSONException