JSONWriter

public class JSONWriter

JSONWriter provides a quick and convenient way of producing JSON text. The texts produced strictly conform to JSON syntax rules. No whitespace is added, so the results are ready for transmission or storage. Each instance of JSONWriter can produce one JSON text.

A JSONWriter instance provides a value method for appending values to the text, and a key method for adding keys before values in objects. There are array and endArray methods that make and bound array values, and object and endObject methods which make and bound object values. All of these methods return the JSONWriter instance, permitting a cascade style. For example,

new JSONWriter(myWriter)
    .object()
        .key("JSON")
        .value("Hello, World!")
    .endObject();

which writes

{"JSON":"Hello, World!"}

The first method called must be array or object. There are no methods for adding commas or colons. JSONWriter adds them for you. Objects and arrays can be nested up to 20 levels deep.

This can sometimes be easier than using a JSONObject to build a string.

Author:JSON.org

Fields

mode

protected char mode

The current mode. Values: ‘a’ (array), ‘d’ (done), ‘i’ (initial), ‘k’ (key), ‘o’ (object).

writer

protected Writer writer

The writer that will receive the output.

Constructors

JSONWriter

public JSONWriter(Writer w)

Make a fresh JSONWriter. It can be used to build one JSON text.

Methods

array

public JSONWriter array()

Begin appending a new array. All values until the balancing endArray will be appended to this array. The endArray method must be called to mark the array’s end.

Throws:
  • JSONException – If the nesting is too deep, or if the object is started in the wrong place (for example as a key or after the end of the outermost array or object).
Returns:

this

endArray

public JSONWriter endArray()

End an array. This method most be called to balance calls to array.

Throws:
Returns:

this

endObject

public JSONWriter endObject()

End an object. This method most be called to balance calls to object.

Throws:
Returns:

this

key

public JSONWriter key(String string)

Append a key. The key will be associated with the next value. In an object, every value must be preceded by a key.

Parameters:
  • string – A key string.
Throws:
  • JSONException – If the key is out of place. For example, keys do not belong in arrays or if the key is null.
Returns:

this

object

public JSONWriter object()

Begin appending a new object. All keys and values until the balancing endObject will be appended to this object. The endObject method must be called to mark the object’s end.

Throws:
  • JSONException – If the nesting is too deep, or if the object is started in the wrong place (for example as a key or after the end of the outermost array or object).
Returns:

this

value

public JSONWriter value(boolean b)

Append either the value true or the value false.

Parameters:
  • b – A boolean.
Throws:
Returns:

this

value

public JSONWriter value(double d)

Append a double value.

Parameters:
  • d – A double.
Throws:
Returns:

this

value

public JSONWriter value(long l)

Append a long value.

Parameters:
  • l – A long.
Throws:
Returns:

this

value

public JSONWriter value(Object object)

Append an object value.

Parameters:
  • object – The object to append. It can be null, or a Boolean, Number, String, JSONObject, or JSONArray, or an object that implements JSONString.
Throws:
Returns:

this