Package javax.json
Interface JsonObject
- All Superinterfaces:
JsonStructure
,JsonValue
,Map<String,
JsonValue>
JsonObject
class represents an immutable JSON object value
(an unordered collection of zero or more name/value pairs).
It also provides unmodifiable map view to the JSON object
name/value mappings.
A JsonObject instance can be created from an input source using
JsonReader.readObject()
. For example:
JsonReader jsonReader = Json.createReader(...);
JsonObject object = jsonReader.readObject();
jsonReader.close();
It can also be built from scratch using a JsonObjectBuilder
.
For example 1: An empty JSON object can be built as follows:
JsonObject object = Json.createObjectBuilder().build();
For example 2: The following JSON
{
"firstName": "John", "lastName": "Smith", "age": 25,
"address" : {
"streetAddress": "21 2nd Street",
"city": "New York",
"state": "NY",
"postalCode": "10021"
},
"phoneNumber": [
{ "type": "home", "number": "212 555-1234" },
{ "type": "fax", "number": "646 555-4567" }
]
}
can be built using :
JsonObject value = Json.createObjectBuilder()
.add("firstName", "John")
.add("lastName", "Smith")
.add("age", 25)
.add("address", Json.createObjectBuilder()
.add("streetAddress", "21 2nd Street")
.add("city", "New York")
.add("state", "NY")
.add("postalCode", "10021"))
.add("phoneNumber", Json.createArrayBuilder()
.add(Json.createObjectBuilder()
.add("type", "home")
.add("number", "212 555-1234"))
.add(Json.createObjectBuilder()
.add("type", "fax")
.add("number", "646 555-4567")))
.build();
JsonObject
can be written to JSON as follows:
JsonWriter writer = ...
JsonObject obj = ...;
writer.writeObject(obj);
JsonObject
values can be JsonObject
, JsonArray
,
JsonString
, JsonNumber
, JsonValue.TRUE
,
JsonValue.FALSE
, JsonValue.NULL
. These values can be
accessed using various accessor methods.
In the above example 2, "John" can be got using
String firstName = object.getString("firstName");
This map object provides read-only access to the JSON object data,
and attempts to modify the map, whether direct or via its collection
views, result in an UnsupportedOperationException
.
The map object's iteration ordering is based on the order in which name/value pairs are added to the corresponding builder or the order in which name/value pairs appear in the corresponding stream.
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Nested Class Summary
Nested classes/interfaces inherited from interface javax.json.JsonValue
JsonValue.ValueType
-
Field Summary
-
Method Summary
Modifier and TypeMethodDescriptionboolean
getBoolean
(String name) Returns the boolean value of the associated mapping for the specified name.boolean
getBoolean
(String name, boolean defaultValue) Returns the boolean value of the associated mapping for the specified name.int
A convenience method forgetJsonNumber(name).intValue()
int
Returns the int value of the associatedJsonNumber
mapping for the specified name.getJsonArray
(String name) Returns the array value to which the specified name is mapped.getJsonNumber
(String name) Returns the number value to which the specified name is mapped.getJsonObject
(String name) Returns the object value to which the specified name is mapped.getJsonString
(String name) Returns the string value to which the specified name is mapped.A convenience method forgetJsonString(name).getString()
Returns the string value of the associatedJsonString
mapping for the specified name.boolean
Returnstrue
if the associated value for the specified name isJsonValue.NULL
.Methods inherited from interface javax.json.JsonValue
getValueType, toString
Methods inherited from interface java.util.Map
clear, compute, computeIfAbsent, computeIfPresent, containsKey, containsValue, entrySet, equals, forEach, get, getOrDefault, hashCode, isEmpty, keySet, merge, put, putAll, putIfAbsent, remove, remove, replace, replace, replaceAll, size, values
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Method Details
-
getJsonArray
Returns the array value to which the specified name is mapped. This is a convenience method for(JsonArray)get(name)
to get the value.- Parameters:
name
- the name whose associated value is to be returned- Returns:
- the array value to which the specified name is mapped, or
null
if this object contains no mapping for the name - Throws:
ClassCastException
- if the value to which the specified name is mapped is not assignable to JsonArray type
-
getJsonObject
Returns the object value to which the specified name is mapped. This is a convenience method for(JsonObject)get(name)
to get the value.- Parameters:
name
- the name whose associated value is to be returned- Returns:
- the object value to which the specified name is mapped, or
null
if this object contains no mapping for the name - Throws:
ClassCastException
- if the value to which the specified name is mapped is not assignable to JsonObject type
-
getJsonNumber
Returns the number value to which the specified name is mapped. This is a convenience method for(JsonNumber)get(name)
to get the value.- Parameters:
name
- the name whose associated value is to be returned- Returns:
- the number value to which the specified name is mapped, or
null
if this object contains no mapping for the name - Throws:
ClassCastException
- if the value to which the specified name is mapped is not assignable to JsonNumber type
-
getJsonString
Returns the string value to which the specified name is mapped. This is a convenience method for(JsonString)get(name)
to get the value.- Parameters:
name
- the name whose associated value is to be returned- Returns:
- the string value to which the specified name is mapped, or
null
if this object contains no mapping for the name - Throws:
ClassCastException
- if the value to which the specified name is mapped is not assignable to JsonString type
-
getString
A convenience method forgetJsonString(name).getString()
- Parameters:
name
- whose associated value is to be returned as String- Returns:
- the String value to which the specified name is mapped
- Throws:
NullPointerException
- if the specified name doesn't have any mappingClassCastException
- if the value for specified name mapping is not assignable to JsonString
-
getString
Returns the string value of the associatedJsonString
mapping for the specified name. IfJsonString
is found, then itsJsonString.getString()
is returned. Otherwise, the specified default value is returned.- Parameters:
name
- whose associated value is to be returned as StringdefaultValue
- a default value to be returned- Returns:
- the string value of the associated mapping for the name, or the default value
-
getInt
A convenience method forgetJsonNumber(name).intValue()
- Parameters:
name
- whose associated value is to be returned as int- Returns:
- the int value to which the specified name is mapped
- Throws:
NullPointerException
- if the specified name doesn't have any mappingClassCastException
- if the value for specified name mapping is not assignable to JsonNumber
-
getInt
Returns the int value of the associatedJsonNumber
mapping for the specified name. IfJsonNumber
is found, then itsJsonNumber.intValue()
is returned. Otherwise, the specified default value is returned.- Parameters:
name
- whose associated value is to be returned as intdefaultValue
- a default value to be returned- Returns:
- the int value of the associated mapping for the name, or the default value
-
getBoolean
Returns the boolean value of the associated mapping for the specified name. If the associated mapping is JsonValue.TRUE, then returns true. If the associated mapping is JsonValue.FALSE, then returns false.- Parameters:
name
- whose associated value is to be returned as boolean- Returns:
- the boolean value to which the specified name is mapped
- Throws:
NullPointerException
- if the specified name doesn't have any mappingClassCastException
- if the value for specified name mapping is not assignable to JsonValue.TRUE or JsonValue.FALSE
-
getBoolean
Returns the boolean value of the associated mapping for the specified name. If the associated mapping is JsonValue.TRUE, then returns true. If the associated mapping is JsonValue.FALSE, then returns false. Otherwise, the specified default value is returned.- Parameters:
name
- whose associated value is to be returned as intdefaultValue
- a default value to be returned- Returns:
- the boolean value of the associated mapping for the name, or the default value
-
isNull
Returnstrue
if the associated value for the specified name isJsonValue.NULL
.- Parameters:
name
- name whose associated value is checked- Returns:
- return true if the associated value is
JsonValue.NUL
, otherwise false - Throws:
NullPointerException
- if the specified name doesn't have any mapping
-