public class JSONObject extends Object
Its external form is a string wrapped in curly braces with colons between the names and values,
and commas between the values and names. The internal form is an object having 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 coercion 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 syntax
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[] names)
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(Map map,
boolean includeSuperClass)
Construct a JSONObject from a Map.
|
JSONObject(Object bean)
Construct a JSONObject from an Object using bean getters.
|
JSONObject(Object bean,
boolean includeSuperClass)
Construct a JSONObject from an Object using bean getters.
|
JSONObject(Object object,
String[] names)
Construct a JSONObject from an Object, using reflection to find the
public members.
|
JSONObject(String source)
Construct a JSONObject from a source JSON text 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.
|
static String[] |
getNames(JSONObject jo)
Get an array of field names from a JSONObject.
|
static String[] |
getNames(Object object)
Get an array of field names from an Object.
|
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 |
putOnce(String key,
Object value)
Put a key/value pair in the JSONObject, but only if the key and the
value are both non-null, and only if there is not already a member
with that name.
|
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.
|
Iterator |
sortedKeys()
Get an enumeration of the keys of the JSONObject.
|
static Object |
stringToValue(String s)
Try to convert a string into a number, boolean, or null.
|
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(JSONObject jo, String[] names) throws JSONException
jo
- A JSONObject.names
- An array of strings.JSONException
- If a value is a non-finite number or if a name is duplicated.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
or a duplicated key.public JSONObject(Map map)
map
- A map object that can be used to initialize the contents of
the JSONObject.public JSONObject(Map map, boolean includeSuperClass)
map
- - A map with Key-Bean data.includeSuperClass
- - Tell whether to include the super class properties.public JSONObject(Object bean)
"get"
or "is"
followed by an uppercase letter,
the method is invoked, and a key and the value returned from the getter method
are put into the new JSONObject.
The key is formed by removing the "get"
or "is"
prefix.
If the second remaining character is not upper case, then the first
character is converted to lower case.
For example, if an object has a method named "getName"
, and
if the result of calling object.getName()
is "Larry Fine"
,
then the JSONObject will contain "name": "Larry Fine"
.bean
- An object that has getter methods that should be used
to make a JSONObject.public JSONObject(Object bean, boolean includeSuperClass)
"get"
or "is"
followed by an uppercase letter,
the method is invoked, and a key and the value returned from the getter method
are put into the new JSONObject.
The key is formed by removing the "get"
or "is"
prefix.
If the second remaining character is not upper case, then the first
character is converted to lower case.bean
- An object that has getter methods that should be used
to make a JSONObject.includeSuperClass
- If true, include the super class properties.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 obtained
from the object.public JSONObject(String source) throws JSONException
source
- A string beginning
with {
(left brace) and ending
with }
(right brace).JSONException
- If there is a syntax error in the source
string or a duplicated key.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 static String[] getNames(JSONObject jo)
public static String[] getNames(Object object)
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 putOnce(String key, Object value) throws JSONException
key
- value
- JSONException
- if the key is a duplicatepublic 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 Iterator sortedKeys()
public static Object stringToValue(String s)
s
- A String.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()
Warning: This method assumes that the data structure is acyclical.
public String toString(int indentFactor) throws JSONException
Warning: This method assumes that the data structure is acyclical.
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
Warning: This method assumes that the data structure is acyclical.
JSONException
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