JsonParser provides forward, read-only access to JSON data using the pull parsing programming model. Writes JSON data to a stream one value at a time Represents an event-based parser that can read JSON data from a stream. The Facebook API gives the search results in the JSON format shown in Listing 2:Ĭontains static methods to create JSON parsers, generators, and their factory objects. Similarly, these object models can be written to an output source (such as OutputStream or Writer) using the class JsonWriter.įor example, let's write code to search Facebook's public posts using the object model API. These object models can also be created from an input source (such as InputStream or Reader) using the interface JsonReader. The resulting model is of type JsonArray. Application code can use the interface JsonArrayBuilder to create models that represent JSON arrays. ![]() The resulting model is of type JsonObject. Application code can use the interface JsonObjectBuilder to create models that represent JSON objects. The object model API uses builder patterns to create these object models from scratch. These are constants defined in the API for null, true, and false JSON values. ![]() JsonObject, JsonArray, JsonString, and JsonNumber are subtypes of JsonValue. Represent data types for values in JSON data. Writes an object model from memory to a stream. Reads JSON data from a stream and creates an object model in memory.Ĭreate an object model or an array model in memory by adding values from application code. Writes JSON data to a stream one value at a time. Main classes in the object model APIĬontains static methods to create JSON readers, writers, builders, and their factory objects. Similarly, JsonArray provides a List view to access the ordered sequence of zero or more values from the model. JsonObject provides a Map view to access the unordered collection of zero or more name/value pairs from the model. Table 1 lists the main classes and interfaces in the object model API. These JSON structures are represented as object models using the Java types JsonObject and JsonArray. It is a high-level API that provides immutable object models for JSON object and array structures. The object model API is similar to the Document Object Model (DOM) API for XML. Similarly, the streaming API provides a way to generate well-formed JSON to a stream by writing one event at a time. The streaming model is adequate for local processing where random access of other parts of the data is not required. Application code can process or discard the parser event and ask for the next event (pull the event). This gives a developer more procedural control over the JSON processing. ![]() The streaming API provides an event-based parser and allows an application developer to ask for the next event rather than handling the event in a callback. It hands over parsing and generation control to the programmer. The streaming API provides a way to parse and generate JSON in a streaming fashion. However, it is often not as efficient as the streaming model and requires more memory. This programming model is the most flexible and enables processing that requires random access to the complete contents of the tree. The tree can then be navigated and queried. The object model API creates a random-access, tree-like structure that represents the JSON data in memory. The Java API for JSON Processing ( JSR 353) provides portable APIs to parse, generate, transform, and query JSON using object model and streaming APIs. All popular websites offer JSON as the data exchange format with their RESTful web services. ![]() JSON is often used in Ajax applications, configurations, databases, and RESTful web services. Example of JSON representation of an object
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