Class JSONObject
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 usingdoubleValue
. Strings that can be coerced usingDouble.valueOf(String)
will be. - When the requested type is an int, other
Number
types will be coerced usingintValue
. Strings that can be coerced usingDouble.valueOf(String)
will be, and then cast to int. - When the requested type is a long, other
Number
types will be coerced usinglongValue
. Strings that can be coerced usingDouble.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
String.valueOf(Object)
. Although null cannot be coerced, the sentinel valueNULL
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 aJSONException
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.
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Field Summary
FieldsModifier and TypeFieldDescriptionprivate final LinkedHashMap
<String, Object> private static final Double
static final Object
A sentinel value used to explicitly define a name with no value. -
Constructor Summary
ConstructorsConstructorDescriptionCreates aJSONObject
with no name/value mappings.JSONObject
(JSONObject copyFrom, String[] names) Creates a newJSONObject
by copying mappings for the listed names from the given object.JSONObject
(JSONTokener readFrom) Creates a newJSONObject
with name/value mappings from the next object in the tokener.JSONObject
(Object bean) Creates a json object from a beanJSONObject
(String json) Creates a newJSONObject
with name/value mappings from the JSON string.JSONObject
(Map copyFrom) Creates a newJSONObject
by copying all name/value mappings from the given map. -
Method Summary
Modifier and TypeMethodDescriptionaccumulate
(String name, Object value) Appendsvalue
to the array already mapped toname
.Appends values to the array mapped toname
.(package private) String
protected void
encode
(JSONStringer stringer) Encodes this object usingJSONStringer
providedReturns the value mapped byname
, or throws if no such mapping exists.boolean
getBoolean
(String name) Returns the value mapped byname
if it exists and is a boolean or can be coerced to a boolean, or throws otherwise.double
Returns the value mapped byname
if it exists and is a double or can be coerced to a double, or throws otherwise.int
Returns the value mapped byname
if it exists and is an int or can be coerced to an int, or throws otherwise.getJSONArray
(String name) Returns the value mapped byname
if it exists and is aJSONArray
, or throws otherwise.getJSONObject
(String name) Returns the value mapped byname
if it exists and is aJSONObject
, or throws otherwise.long
Returns the value mapped byname
if it exists and is a long or can be coerced to a long, or throws otherwise.static String[]
Returns the value mapped byname
if it exists, coercing it if necessary, or throws if no such mapping exists.boolean
Returns true if this object has a mapping forname
.private void
init
(JSONTokener readFrom) private void
boolean
Returns true if this object has no mapping forname
or if it has a mapping whose value isNULL
.keys()
Returns an iterator of theString
names in this object.keySet()
Returns the set ofString
names in this object.int
length()
Returns the number of name/value mappings in this object.names()
Returns an array containing the string names in this object.static String
numberToString
(Number number) Encodes the number as a JSON string.objectAsMap
(Object bean) Creates a name-value map from a beanReturns the value mapped byname
, or null if no such mapping exists.boolean
optBoolean
(String name) Returns the value mapped byname
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 byname
if it exists and is a boolean or can be coerced to a boolean, orfallback
otherwise.double
Returns the value mapped byname
if it exists and is a double or can be coerced to a double, orNaN
otherwise.double
Returns the value mapped byname
if it exists and is a double or can be coerced to a double, orfallback
otherwise.int
Returns the value mapped byname
if it exists and is an int or can be coerced to an int, or 0 otherwise.int
Returns the value mapped byname
if it exists and is an int or can be coerced to an int, orfallback
otherwise.optJSONArray
(String name) Returns the value mapped byname
if it exists and is aJSONArray
, or null otherwise.optJSONObject
(String name) Returns the value mapped byname
if it exists and is aJSONObject
, or null otherwise.long
Returns the value mapped byname
if it exists and is a long or can be coerced to a long, or 0 otherwise.long
Returns the value mapped byname
if it exists and is a long or can be coerced to a long, orfallback
otherwise.Returns the value mapped byname
if it exists, coercing it if necessary, or the empty string if no such mapping exists.Returns the value mapped byname
if it exists, coercing it if necessary, orfallback
if no such mapping exists.Mapsname
tovalue
, clobbering any existing name/value mapping with the same name.Mapsname
tovalue
, clobbering any existing name/value mapping with the same name.Mapsname
tovalue
, clobbering any existing name/value mapping with the same name.Mapsname
tovalue
, clobbering any existing name/value mapping with the same name.Mapsname
tovalue
, clobbering any existing name/value mapping with the same name.Equivalent toput(name, value)
when both parameters are non-null; does nothing otherwise.static String
Encodesdata
as a JSON string.Removes the named mapping if it exists; does nothing otherwise.toJSONArray
(JSONArray names) Returns an array with the values corresponding tonames
.toString()
Encodes this object as a compact JSON string, such as:toString
(int indentSpaces) Encodes this object as a human readable JSON string for debugging, such as:toString
(JSONStringer stringer) Encodes this object usingJSONStringer
providedstatic Object
Wraps the given object if necessary.
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Field Details
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NEGATIVE_ZERO
-
NULL
A sentinel value used to explicitly define a name with no value. Unlikenull
, names with this value:- show up in the
names()
array - show up in the
keys()
iterator - return
true
forhas(String)
- do not throw on
get(String)
- are included in the encoded JSON string.
This value violates the general contract of
Object.equals(java.lang.Object)
by returning true when compared tonull
. ItstoString()
method returns "null". - show up in the
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nameValuePairs
-
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Constructor Details
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JSONObject
public JSONObject()Creates aJSONObject
with no name/value mappings. -
JSONObject
Creates a newJSONObject
by copying all name/value mappings from the given map.- Parameters:
copyFrom
- a map whose keys are of typeString
and whose values are of supported types.- Throws:
NullPointerException
- if any of the map's keys are null.
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JSONObject
Creates a newJSONObject
with name/value mappings from the next object in the tokener.- Parameters:
readFrom
- a tokener whose nextValue() method will yield aJSONObject
.- Throws:
JSONException
- if the parse fails or doesn't yield aJSONObject
.
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JSONObject
Creates a newJSONObject
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 aJSONObject
.
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JSONObject
Creates a newJSONObject
by copying mappings for the listed names from the given object. Names that aren't present incopyFrom
will be skipped.- Parameters:
copyFrom
- The source object.names
- The names of the fields to copy.- Throws:
JSONException
- On internal errors. Shouldn't happen.
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JSONObject
Creates a json object from a bean- Parameters:
bean
- the bean to create the json object from- Throws:
JSONException
- If there is an exception while reading the bean
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Method Details
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init
-
init
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objectAsMap
Creates a name-value map from a bean- Parameters:
bean
- the bean to create the map from- Returns:
- name-value map representing the bean
- Throws:
JSONException
- If there is an exception while reading the bean
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getNames
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length
public int length()Returns the number of name/value mappings in this object.- Returns:
- the length of this.
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put
Mapsname
tovalue
, clobbering any existing name/value mapping with the same name.- Parameters:
name
- The name of the value to insert.value
- The value to insert.- Returns:
- this object.
- Throws:
JSONException
- Should not be possible.
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put
Mapsname
tovalue
, clobbering any existing name/value mapping with the same name.- Parameters:
name
- The name for the new value.value
- a finite value. May not beNaNs
orinfinities
.- Returns:
- this object.
- Throws:
JSONException
- if value is NaN or infinite.
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put
Mapsname
tovalue
, clobbering any existing name/value mapping with the same name.- Parameters:
name
- The name for the new value.value
- The new value.- Returns:
- this object.
- Throws:
JSONException
- Should not be possible.
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put
Mapsname
tovalue
, clobbering any existing name/value mapping with the same name.- Parameters:
name
- The name of the new value.value
- The new value to insert.- Returns:
- this object.
- Throws:
JSONException
- Should not be possible.
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put
Mapsname
tovalue
, clobbering any existing name/value mapping with the same name. If the value isnull
, any existing mapping forname
is removed.- Parameters:
name
- The name of the new value.value
- aJSONObject
,JSONArray
, String, Boolean, Integer, Long, Double,NULL
, ornull
. May not beNaNs
orinfinities
. If value is Map or Collection the value is wrapped using corresponding JSONObject(map) or JSONArray(collection) object. This behavior is considered unsafe and is added for compatibility with original 'org.json' package only.- Returns:
- this object.
- Throws:
JSONException
- if the value is an invalid double (infinite or NaN).
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putOpt
Equivalent toput(name, value)
when both parameters are non-null; does nothing otherwise.- Parameters:
name
- The name of the value to insert.value
- The value to insert.- Returns:
- this object.
- Throws:
JSONException
- if the value is an invalid double (infinite or NaN).
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accumulate
Appendsvalue
to the array already mapped toname
. If this object has no mapping forname
, 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 toname
. In aggregate, this allows values to be added to a mapping one at a time. Note thatappend(String, Object)
provides better semantics. In particular, the mapping forname
will always be aJSONArray
. Usingaccumulate
will result in either aJSONArray
or a mapping whose type is the type ofvalue
depending on the number of calls to it.- Parameters:
name
- The name of the field to change.value
- aJSONObject
,JSONArray
, String, Boolean, Integer, Long, Double,NULL
or null. May not beNaNs
orinfinities
.- Returns:
- this object after mutation.
- Throws:
JSONException
- If the object being added is an invalid number.
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append
Appends values to the array mapped toname
. A newJSONArray
mapping forname
will be inserted if no mapping exists. If the existing mapping forname
is not aJSONArray
, aJSONException
will be thrown.- Parameters:
name
- The name of the array to which the value should be appended.value
- The value to append.- Returns:
- this object.
- Throws:
JSONException
- ifname
isnull
or if the mapping forname
is non-null and is not aJSONArray
.
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checkName
- Throws:
JSONException
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remove
Removes the named mapping if it exists; does nothing otherwise.- Parameters:
name
- The name of the mapping to remove.- Returns:
- the value previously mapped by
name
, or null if there was no such mapping.
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isNull
Returns true if this object has no mapping forname
or if it has a mapping whose value isNULL
.- Parameters:
name
- The name of the value to check on.- Returns:
- true if the field doesn't exist or is null.
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has
Returns true if this object has a mapping forname
. The mapping may beNULL
.- Parameters:
name
- The name of the value to check on.- Returns:
- true if this object has a field named
name
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get
Returns the value mapped byname
, or throws if no such mapping exists.- Parameters:
name
- The name of the value to get.- Returns:
- The value.
- Throws:
JSONException
- if no such mapping exists.
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opt
Returns the value mapped byname
, or null if no such mapping exists.- Parameters:
name
- The name of the value to get.- Returns:
- The value.
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getBoolean
Returns the value mapped byname
if it exists and is a boolean or can be coerced to a boolean, or throws otherwise.- Parameters:
name
- The name of the field we want.- Returns:
- The selected value if it exists.
- Throws:
JSONException
- if the mapping doesn't exist or cannot be coerced to a boolean.
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optBoolean
Returns the value mapped byname
if it exists and is a boolean or can be coerced to a boolean, or false otherwise.- Parameters:
name
- The name of the field we want.- Returns:
- The selected value if it exists.
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optBoolean
Returns the value mapped byname
if it exists and is a boolean or can be coerced to a boolean, orfallback
otherwise.- Parameters:
name
- The name of the field we want.fallback
- The value to return if the field isn't there.- Returns:
- The selected value or the fallback.
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getDouble
Returns the value mapped byname
if it exists and is a double or can be coerced to a double, or throws otherwise.- Parameters:
name
- The name of the field we want.- Returns:
- The selected value if it exists.
- Throws:
JSONException
- if the mapping doesn't exist or cannot be coerced to a double.
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optDouble
Returns the value mapped byname
if it exists and is a double or can be coerced to a double, orNaN
otherwise.- Parameters:
name
- The name of the field we want.- Returns:
- The selected value if it exists.
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optDouble
Returns the value mapped byname
if it exists and is a double or can be coerced to a double, orfallback
otherwise.- Parameters:
name
- The name of the field we want.fallback
- The value to return if the field isn't there.- Returns:
- The selected value or the fallback.
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getInt
Returns the value mapped byname
if it exists and is an int or can be coerced to an int, or throws otherwise.- Parameters:
name
- The name of the field we want.- Returns:
- The selected value if it exists.
- Throws:
JSONException
- if the mapping doesn't exist or cannot be coerced to an int.
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optInt
Returns the value mapped byname
if it exists and is an int or can be coerced to an int, or 0 otherwise.- Parameters:
name
- The name of the field we want.- Returns:
- The selected value if it exists.
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optInt
Returns the value mapped byname
if it exists and is an int or can be coerced to an int, orfallback
otherwise.- Parameters:
name
- The name of the field we want.fallback
- The value to return if the field isn't there.- Returns:
- The selected value or the fallback.
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getLong
Returns the value mapped byname
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 without loss.- Parameters:
name
- The name of the field that we want.- Returns:
- The value of the field.
- Throws:
JSONException
- if the mapping doesn't exist or cannot be coerced to a long.
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optLong
Returns the value mapped byname
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
- The name of the field we want.- Returns:
- The selected value.
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optLong
Returns the value mapped byname
if it exists and is a long or can be coerced to a long, orfallback
otherwise. Note that JSON represents numbers as doubles, so this is lossy; use strings to transfer numbers via JSON.- Parameters:
name
- The name of the field we want.fallback
- The value to return if the field isn't there.- Returns:
- The selected value or the fallback.
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getString
Returns the value mapped byname
if it exists, coercing it if necessary, or throws if no such mapping exists.- Parameters:
name
- The name of the field we want.- Returns:
- The value of the field.
- Throws:
JSONException
- if no such mapping exists.
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optString
Returns the value mapped byname
if it exists, coercing it if necessary, or the empty string if no such mapping exists.- Parameters:
name
- The name of the field we want.- Returns:
- The value of the field.
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optString
Returns the value mapped byname
if it exists, coercing it if necessary, orfallback
if no such mapping exists.- Parameters:
name
- The name of the field that we want.fallback
- The value to return if the field doesn't exist.- Returns:
- The value of the field or fallback.
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getJSONArray
Returns the value mapped byname
if it exists and is aJSONArray
, or throws otherwise.- Parameters:
name
- The field we want to get.- Returns:
- The value of the field (if it is a JSONArray.
- Throws:
JSONException
- if the mapping doesn't exist or is not aJSONArray
.
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optJSONArray
Returns the value mapped byname
if it exists and is aJSONArray
, or null otherwise.- Parameters:
name
- The name of the field we want.- Returns:
- The value of the specified field (assuming it is a JSNOArray
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getJSONObject
Returns the value mapped byname
if it exists and is aJSONObject
, or throws otherwise.- Parameters:
name
- The name of the field that we want.- Returns:
- a specified field value (if it is a JSONObject)
- Throws:
JSONException
- if the mapping doesn't exist or is not aJSONObject
.
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optJSONObject
Returns the value mapped byname
if it exists and is aJSONObject
, or null otherwise.- Parameters:
name
- The name of the value we want.- Returns:
- The specified value.
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toJSONArray
Returns an array with the values corresponding tonames
. The array contains null for names that aren't mapped. This method returns null ifnames
is either null or empty.- Parameters:
names
- The names of the fields that we want the values for.- Returns:
- The selected values.
- Throws:
JSONException
- On internal errors. Shouldn't happen.
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keys
Returns an iterator of theString
names in this object. The returned iterator supportsremove
, 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:
- an iterator over the keys.
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keySet
Returns the set ofString
names in this object. The returned set is a view of the keys in this object.Set.remove(Object)
will remove the corresponding mapping from this object and set iterator behaviour is undefined if this object is modified after it is returned. Seekeys()
.- Returns:
- The names in this object.
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names
Returns an array containing the string names in this object. This method returns null if this object contains no mappings.- Returns:
- the names.
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toString
Encodes this object as a compact JSON string, such as:{"query":"Pizza","locations":[94043,90210]}
Note 1: this method will not output any fields with 'null' value. OverrideJSONStringer.entry(java.util.Map.Entry<java.lang.String, java.lang.Object>)
method to have nulls printed. Note 2: this method will suppress any internal exceptions. UsetoString(JSONStringer)
method directly to handle exceptions manually. -
toString
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.- Returns:
- The string containing the pretty form of this.
- Throws:
JSONException
- On internal errors. Shouldn't happen.
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toString
Encodes this object usingJSONStringer
provided- Parameters:
stringer
- -JSONStringer
to be used for serialization- Returns:
- The string representation of this.
- Throws:
JSONException
- On internal errors. Shouldn't happen.
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encode
Encodes this object usingJSONStringer
provided- Parameters:
stringer
- -JSONStringer
to be used for serialization- Throws:
JSONException
- On internal errors. Shouldn't happen.
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numberToString
Encodes the number as a JSON string.- Parameters:
number
- a finite value. May not beNaNs
orinfinities
.- Returns:
- The encoded number in string form.
- Throws:
JSONException
- On internal errors. Shouldn't happen.
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quote
Encodesdata
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.- Returns:
- the quoted string.
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wrap
Wraps the given object if necessary.If the object is null or , returns
NULL
. If the object is aJSONArray
orJSONObject
, no wrapping is necessary. If the object isNULL
, no wrapping is necessary. If the object is an array orCollection
, returns an equivalentJSONArray
. If the object is aMap
, returns an equivalentJSONObject
. If the object is a primitive wrapper type orString
, returns the object. If the object is from ajava
package, returns the result oftoString
. If the object is some other kind of object then it is assumed to be a bean and is converted to a JSONObject. If wrapping fails, returns null.- Parameters:
o
- The object to wrap.- Returns:
- The wrapped (if necessary) form of the object {$code o}
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