public class JSONObject extends Object implements Serializable
get
and opt
methods for accessing the values by name, and put
methods for adding or
replacing values by name. The values can be any of these types: Boolean
, JSONArray
,
JSONObject
, Number
, String
, or the JSONObject.NULL
object. A JSONObject
constructor can be used to convert an external form JSON text into an internal form whose values can be retrieved with the
get
and opt
methods, or to convert values into a JSON text using the put
and
toString
methods. A get
method returns a value if one can be found, and throws an exception if one
cannot be found. An opt
method returns a default value instead of throwing an exception, and so is useful for
obtaining optional values.
The generic get()
and opt()
methods return an object, which you can cast or query for type. There
are also typed get
and opt
methods that do type checking and type coersion for you.
The put
methods adds values to an object. For example,
myString = new JSONObject().put("JSON", "Hello, World!").toString();produces the string
{"JSON": "Hello, World"}
.
The texts produced by the toString
methods strictly conform to the JSON sysntax rules. The constructors are more
forgiving in the texts they will accept:
,
(comma) may appear just before the closing brace.'
(single quote).{ } [ ] / \ : , = ; #
and if
they do not look like numbers and if they are not the reserved words true
, false
, or
null
.=
or =>
as well as by :
.;
(semicolon) as well as by ,
(comma).0-
(octal) or 0x-
(hex) prefix.Modifier and Type | Field and Description |
---|---|
static Object |
NULL
It is sometimes more convenient and less ambiguous to have a
NULL object than to use Java's
null value. |
Constructor and Description |
---|
JSONObject()
Construct an empty JSONObject.
|
JSONObject(JSONObject jo,
String[] sa)
Construct a JSONObject from a subset of another JSONObject.
|
JSONObject(JSONTokener x)
Construct a JSONObject from a JSONTokener.
|
JSONObject(Map map)
Construct a JSONObject from a Map.
|
JSONObject(Object object,
String[] names)
Construct a JSONObject from an Object, using reflection to find the public members.
|
JSONObject(String string)
Construct a JSONObject from a string.
|
Modifier and Type | Method and Description |
---|---|
JSONObject |
accumulate(String key,
Object value)
Accumulate values under a key.
|
JSONObject |
append(String key,
Object value)
Append values to the array under a key.
|
static String |
doubleToString(double d)
Produce a string from a double.
|
Object |
get(String key)
Get the value object associated with a key.
|
boolean |
getBoolean(String key)
Get the boolean value associated with a key.
|
double |
getDouble(String key)
Get the double value associated with a key.
|
int |
getInt(String key)
Get the int value associated with a key.
|
JSONArray |
getJSONArray(String key)
Get the JSONArray value associated with a key.
|
JSONObject |
getJSONObject(String key)
Get the JSONObject value associated with a key.
|
long |
getLong(String key)
Get the long value associated with a key.
|
String |
getString(String key)
Get the string associated with a key.
|
boolean |
has(String key)
Determine if the JSONObject contains a specific key.
|
boolean |
isNull(String key)
Determine if the value associated with the key is null or if there is no value.
|
Iterator |
keys()
Get an enumeration of the keys of the JSONObject.
|
int |
length()
Get the number of keys stored in the JSONObject.
|
JSONArray |
names()
Produce a JSONArray containing the names of the elements of this JSONObject.
|
static String |
numberToString(Number n)
Produce a string from a Number.
|
Object |
opt(String key)
Get an optional value associated with a key.
|
boolean |
optBoolean(String key)
Get an optional boolean associated with a key.
|
boolean |
optBoolean(String key,
boolean defaultValue)
Get an optional boolean associated with a key.
|
double |
optDouble(String key)
Get an optional double associated with a key, or NaN if there is no such key or if its value is not a number.
|
double |
optDouble(String key,
double defaultValue)
Get an optional double associated with a key, or the defaultValue if there is no such key or if its value is not a
number.
|
int |
optInt(String key)
Get an optional int value associated with a key, or zero if there is no such key or if the value is not a number.
|
int |
optInt(String key,
int defaultValue)
Get an optional int value associated with a key, or the default if there is no such key or if the value is not a number.
|
JSONArray |
optJSONArray(String key)
Get an optional JSONArray associated with a key.
|
JSONObject |
optJSONObject(String key)
Get an optional JSONObject associated with a key.
|
long |
optLong(String key)
Get an optional long value associated with a key, or zero if there is no such key or if the value is not a number.
|
long |
optLong(String key,
long defaultValue)
Get an optional long value associated with a key, or the default if there is no such key or if the value is not a number.
|
String |
optString(String key)
Get an optional string associated with a key.
|
String |
optString(String key,
String defaultValue)
Get an optional string associated with a key.
|
JSONObject |
put(String key,
boolean value)
Put a key/boolean pair in the JSONObject.
|
JSONObject |
put(String key,
Collection value)
Put a key/value pair in the JSONObject, where the value will be a JSONArray which is produced from a Collection.
|
JSONObject |
put(String key,
double value)
Put a key/double pair in the JSONObject.
|
JSONObject |
put(String key,
int value)
Put a key/int pair in the JSONObject.
|
JSONObject |
put(String key,
long value)
Put a key/long pair in the JSONObject.
|
JSONObject |
put(String key,
Map value)
Put a key/value pair in the JSONObject, where the value will be a JSONObject which is produced from a Map.
|
JSONObject |
put(String key,
Object value)
Put a key/value pair in the JSONObject.
|
JSONObject |
putOpt(String key,
Object value)
Put a key/value pair in the JSONObject, but only if the key and the value are both non-null.
|
static String |
quote(String string)
Produce a string in double quotes with backslash sequences in all the right places.
|
Object |
remove(String key)
Remove a name and its value, if present.
|
JSONArray |
toJSONArray(JSONArray names)
Produce a JSONArray containing the values of the members of this JSONObject.
|
String |
toString()
Make a JSON text of this JSONObject.
|
String |
toString(int indentFactor)
Make a prettyprinted JSON text of this JSONObject.
|
Writer |
write(Writer writer)
Write the contents of the JSONObject as JSON text to a writer.
|
public static final Object NULL
NULL
object than to use Java's
null
value. JSONObject.NULL.equals(null)
returns true
.
JSONObject.NULL.toString()
returns "null"
.public JSONObject()
public JSONObject(JSONTokener x) throws JSONException
x
- A JSONTokener object containing the source string.JSONException
- If there is a syntax error in the source string.public JSONObject(Map map)
map
- A map object that can be used to initialize the contents of the JSONObject.public JSONObject(String string) throws JSONException
string
- A string beginning with {
(left brace) and ending with }
(right brace).JSONException
- If there is a syntax error in the source string.public JSONObject(JSONObject jo, String[] sa) throws JSONException
jo
- A JSONObject.sa
- An array of strings.JSONException
- If a value is a non-finite number.public JSONObject(Object object, String[] names)
object
- An object that has fields that should be used to make a JSONObject.names
- An array of strings, the names of the fields to be used from the object.public JSONObject accumulate(String key, Object value) throws JSONException
key
- A key string.value
- An object to be accumulated under the key.JSONException
- If the value is an invalid number or if the key is null.public JSONObject append(String key, Object value) throws JSONException
key
- A key string.value
- An object to be accumulated under the key.JSONException
- If the key is null or if the current value associated with the key is not a JSONArray.public static String doubleToString(double d)
d
- A double.public Object get(String key) throws JSONException
key
- A key string.JSONException
- if the key is not found.public boolean getBoolean(String key) throws JSONException
key
- A key string.JSONException
- if the value is not a Boolean or the String "true" or "false".public double getDouble(String key) throws JSONException
key
- A key string.JSONException
- if the key is not found or if the value is not a Number object and cannot be converted to a number.public int getInt(String key) throws JSONException
key
- A key string.JSONException
- if the key is not found or if the value cannot be converted to an integer.public JSONArray getJSONArray(String key) throws JSONException
key
- A key string.JSONException
- if the key is not found or if the value is not a JSONArray.public JSONObject getJSONObject(String key) throws JSONException
key
- A key string.JSONException
- if the key is not found or if the value is not a JSONObject.public long getLong(String key) throws JSONException
key
- A key string.JSONException
- if the key is not found or if the value cannot be converted to a long.public String getString(String key) throws JSONException
key
- A key string.JSONException
- if the key is not found.public boolean has(String key)
key
- A key string.public boolean isNull(String key)
key
- A key string.public Iterator keys()
public int length()
public JSONArray names()
public static String numberToString(Number n) throws JSONException
n
- A NumberJSONException
- If n is a non-finite number.public Object opt(String key)
key
- A key string.public boolean optBoolean(String key)
key
- A key string.public boolean optBoolean(String key, boolean defaultValue)
key
- A key string.defaultValue
- The default.public JSONObject put(String key, Collection value) throws JSONException
key
- A key string.value
- A Collection value.JSONException
public double optDouble(String key)
key
- A string which is the key.public double optDouble(String key, double defaultValue)
key
- A key string.defaultValue
- The default.public int optInt(String key)
key
- A key string.public int optInt(String key, int defaultValue)
key
- A key string.defaultValue
- The default.public JSONArray optJSONArray(String key)
key
- A key string.public JSONObject optJSONObject(String key)
key
- A key string.public long optLong(String key)
key
- A key string.public long optLong(String key, long defaultValue)
key
- A key string.defaultValue
- The default.public String optString(String key)
key
- A key string.public String optString(String key, String defaultValue)
key
- A key string.defaultValue
- The default.public JSONObject put(String key, boolean value) throws JSONException
key
- A key string.value
- A boolean which is the value.JSONException
- If the key is null.public JSONObject put(String key, double value) throws JSONException
key
- A key string.value
- A double which is the value.JSONException
- If the key is null or if the number is invalid.public JSONObject put(String key, int value) throws JSONException
key
- A key string.value
- An int which is the value.JSONException
- If the key is null.public JSONObject put(String key, long value) throws JSONException
key
- A key string.value
- A long which is the value.JSONException
- If the key is null.public JSONObject put(String key, Map value) throws JSONException
key
- A key string.value
- A Map value.JSONException
public JSONObject put(String key, Object value) throws JSONException
key
- A key string.value
- An object which is the value. It should be of one of these types: Boolean, Double, Integer, JSONArray,
JSONObject, Long, String, or the JSONObject.NULL object.JSONException
- If the value is non-finite number or if the key is null.public JSONObject putOpt(String key, Object value) throws JSONException
key
- A key string.value
- An object which is the value. It should be of one of these types: Boolean, Double, Integer, JSONArray,
JSONObject, Long, String, or the JSONObject.NULL object.JSONException
- If the value is a non-finite number.public static String quote(String string)
string
- A Stringpublic Object remove(String key)
key
- The name to be removed.public JSONArray toJSONArray(JSONArray names) throws JSONException
names
- A JSONArray containing a list of key strings. This determines the sequence of the values in the result.JSONException
- If any of the values are non-finite numbers.public String toString()
public String toString(int indentFactor) throws JSONException
indentFactor
- The number of spaces to add to each level of indentation.{
(left brace) and ending with }
(right brace).JSONException
- If the object contains an invalid number.public Writer write(Writer writer) throws JSONException
JSONException
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