public class JSONObject extends Object
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.
Number
types will
be coerced using doubleValue
. Strings
that can be coerced using Double.valueOf(String)
will be.
Number
types will
be coerced using intValue
. Strings
that can be coerced using Double.valueOf(String)
will be,
and then cast to int.
Number
types will
be coerced using longValue
. Strings
that can be coerced using Double.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.
String.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:
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.
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.
Modifier and Type | Field and Description |
---|---|
static Object |
NULL
A sentinel value used to explicitly define a name with no value.
|
Constructor and Description |
---|
JSONObject()
Creates a
JSONObject with no name/value mappings. |
JSONObject(JSONObject copyFrom,
String[] names)
Creates a new
JSONObject by copying mappings for the listed names
from the given object. |
JSONObject(JSONTokener readFrom)
Creates a new
JSONObject with name/value mappings from the next
object in the tokener. |
JSONObject(Map copyFrom)
Creates a new
JSONObject by copying all name/value mappings from
the given map. |
JSONObject(String json)
Creates a new
JSONObject with name/value mappings from the JSON
string. |
Modifier and Type | Method and Description |
---|---|
JSONObject |
accumulate(String name,
Object value)
Appends
value to the array already mapped to name . |
JSONObject |
append(String name,
Object value)
Appends values to the array 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. |
Set<String> |
keySet()
Returns the set of
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)
Returns the value mapped by
name if it exists and is a double or
can be coerced to a double, or NaN 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. |
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. |
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. |
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,
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 |
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 |
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:
|
String |
toString(int indentSpaces)
Encodes this object as a human readable JSON string for debugging, such
as:
|
static Object |
wrap(Object o)
Wraps the given object if necessary.
|
@NonNull public static final Object NULL
null
, names with this value:
names()
array
keys()
iterator
true
for has(String)
get(String)
This value violates the general contract of Object.equals(java.lang.Object)
by
returning true when compared to null
. Its toString()
method returns "null".
public JSONObject()
JSONObject
with no name/value mappings.public JSONObject(@NonNull Map copyFrom)
JSONObject
by copying all name/value mappings from
the given map.copyFrom
- a map whose keys are of type String
and whose
values are of supported types.NullPointerException
- if any of the map's keys are null.public JSONObject(@NonNull JSONTokener readFrom) throws JSONException
JSONObject
with name/value mappings from the next
object in the tokener.readFrom
- a tokener whose nextValue() method will yield a
JSONObject
.JSONException
- if the parse fails or doesn't yield a
JSONObject
.public JSONObject(@NonNull String json) throws JSONException
JSONObject
with name/value mappings from the JSON
string.json
- a JSON-encoded string containing an object.JSONException
- if the parse fails or doesn't yield a JSONObject
.public JSONObject(@NonNull JSONObject copyFrom, @NonNull String[] names) throws JSONException
JSONObject
by copying mappings for the listed names
from the given object. Names that aren't present in copyFrom
will
be skipped.JSONException
public int length()
@NonNull public JSONObject put(@NonNull String name, boolean value) throws JSONException
name
to value
, clobbering any existing name/value
mapping with the same name.JSONException
@NonNull public JSONObject put(@NonNull String name, double value) throws JSONException
name
to value
, clobbering any existing name/value
mapping with the same name.value
- a finite value. May not be NaNs
or
infinities
.JSONException
@NonNull public JSONObject put(@NonNull String name, int value) throws JSONException
name
to value
, clobbering any existing name/value
mapping with the same name.JSONException
@NonNull public JSONObject put(@NonNull String name, long value) throws JSONException
name
to value
, clobbering any existing name/value
mapping with the same name.JSONException
@NonNull public JSONObject put(@NonNull String name, @Nullable Object value) throws JSONException
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.value
- a JSONObject
, JSONArray
, String, Boolean,
Integer, Long, Double, NULL
, or null
. May not be
NaNs
or infinities
.JSONException
@NonNull public JSONObject putOpt(@Nullable String name, @Nullable Object value) throws JSONException
put(name, value)
when both parameters are non-null;
does nothing otherwise.JSONException
@NonNull public JSONObject accumulate(@NonNull String name, @Nullable Object value) throws JSONException
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.
value
- a JSONObject
, JSONArray
, String, Boolean,
Integer, Long, Double, NULL
or null. May not be NaNs
or infinities
.JSONException
public JSONObject append(String name, Object value) throws JSONException
name
. A new JSONArray
mapping for name
will be inserted if no mapping exists. If the existing
mapping for name
is not a JSONArray
, a JSONException
will be thrown.JSONException
- if name
is null
or if the mapping for
name
is non-null and is not a JSONArray
.@Nullable public Object remove(@Nullable String name)
name
, or null if there was
no such mapping.public boolean isNull(@Nullable String name)
name
or if it has
a mapping whose value is NULL
.public boolean has(@Nullable String name)
name
. The mapping
may be NULL
.@NonNull public Object get(@NonNull String name) throws JSONException
name
, or throws if no such mapping exists.JSONException
- if no such mapping exists.@Nullable public Object opt(@Nullable String name)
name
, or null if no such mapping
exists.public boolean getBoolean(@NonNull String name) throws JSONException
name
if it exists and is a boolean or
can be coerced to a boolean, or throws otherwise.JSONException
- if the mapping doesn't exist or cannot be coerced
to a boolean.public boolean optBoolean(@Nullable String name)
name
if it exists and is a boolean or
can be coerced to a boolean, or false otherwise.public boolean optBoolean(@Nullable String name, boolean fallback)
name
if it exists and is a boolean or
can be coerced to a boolean, or fallback
otherwise.public double getDouble(@NonNull String name) throws JSONException
name
if it exists and is a double or
can be coerced to a double, or throws otherwise.JSONException
- if the mapping doesn't exist or cannot be coerced
to a double.public double optDouble(@Nullable String name)
name
if it exists and is a double or
can be coerced to a double, or NaN
otherwise.public double optDouble(@Nullable String name, double fallback)
name
if it exists and is a double or
can be coerced to a double, or fallback
otherwise.public int getInt(@NonNull String name) throws JSONException
name
if it exists and is an int or
can be coerced to an int, or throws otherwise.JSONException
- if the mapping doesn't exist or cannot be coerced
to an int.public int optInt(@Nullable String name)
name
if it exists and is an int or
can be coerced to an int, or 0 otherwise.public int optInt(@Nullable String name, int fallback)
name
if it exists and is an int or
can be coerced to an int, or fallback
otherwise.public long getLong(@NonNull String name) throws JSONException
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.JSONException
- if the mapping doesn't exist or cannot be coerced
to a long.public long optLong(@Nullable String name)
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.public long optLong(@Nullable String name, long fallback)
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.@NonNull public String getString(@NonNull String name) throws JSONException
name
if it exists, coercing it if
necessary, or throws if no such mapping exists.JSONException
- if no such mapping exists.@NonNull public String optString(@Nullable String name)
name
if it exists, coercing it if
necessary, or the empty string if no such mapping exists.@NonNull public String optString(@Nullable String name, @NonNull String fallback)
name
if it exists, coercing it if
necessary, or fallback
if no such mapping exists.@NonNull public JSONArray getJSONArray(@NonNull String name) throws JSONException
name
if it exists and is a JSONArray
, or throws otherwise.JSONException
- if the mapping doesn't exist or is not a JSONArray
.@Nullable public JSONArray optJSONArray(@Nullable String name)
name
if it exists and is a JSONArray
, or null otherwise.@NonNull public JSONObject getJSONObject(@NonNull String name) throws JSONException
name
if it exists and is a JSONObject
, or throws otherwise.JSONException
- if the mapping doesn't exist or is not a JSONObject
.@Nullable public JSONObject optJSONObject(@Nullable String name)
name
if it exists and is a JSONObject
, or null otherwise.@Nullable public JSONArray toJSONArray(@Nullable JSONArray names) throws JSONException
names
. The
array contains null for names that aren't mapped. This method returns
null if names
is either null or empty.JSONException
@NonNull public Iterator<String> keys()
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 Set<String> keySet()
String
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.
See keys()
.
@Nullable public JSONArray names()
@NonNull public String toString()
{"query":"Pizza","locations":[94043,90210]}
@NonNull public String toString(int indentSpaces) throws JSONException
{ "query": "Pizza", "locations": [ 94043, 90210 ] }
indentSpaces
- the number of spaces to indent for each level of
nesting.JSONException
@NonNull public static String numberToString(@NonNull Number number) throws JSONException
number
- a finite value. May not be NaNs
or
infinities
.JSONException
@NonNull public static String quote(@Nullable String data)
data
as a JSON string. This applies quotes and any
necessary character escaping.data
- the string to encode. Null will be interpreted as an empty
string.@Nullable public static Object wrap(@Nullable Object o)
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.