All Implemented Interfaces:

java.io.Closeable , java.lang.AutoCloseable
```
public abstract class JsonReader
 implements Closeable
                    
```
Reads a JSON (RFC 7159) encoded value as a stream of tokens. This stream includes both literal values (strings, numbers, booleans, and nulls) as well as the begin and end delimiters of objects and arrays. The tokens are traversed in depth-first order, the same order that they appear in the JSON document. Within JSON objects, name/value pairs are represented by a single token.
Parsing JSONTo create a recursive descent parser for your own JSON streams, first create an entry point method that creates a {@code JsonReader}.
Next, create handler methods for each structure in your JSON text. You'll need a method for each object type and for each array type.
- Within array handling methods, first call to consume the array's opening bracket. Then create a while loop that accumulates values, terminating when hasNext is false. Finally, read the array's closing bracket by calling .
- Within object handling methods, first call to consume the object's opening brace. Then create a while loop that assigns values to local variables based on their name. This loop should terminate when hasNext is false. Finally, read the object's closing brace by calling endObject.
When a nested object or array is encountered, delegate to the corresponding handler method.
When an unknown name is encountered, strict parsers should fail with an exception. Lenient parsers should call skipValue to recursively skip the value's nested tokens, which may otherwise conflict.
If a value may be null, you should first check using peek. Null literals can be consumed using skipValue.
ExampleSuppose we'd like to parse a stream of messages such as the following:
```
 {@code * [ * { * "id": 912345678901, * "text": "How do I read a JSON stream in Java?", * "geo": null, * "user": { * "name": "json_newb", * "followers_count": 41 * } * }, * { * "id": 912345678902, * "text": "@json_newb just use JsonReader!", * "geo": [50.454722, -104.606667], * "user": { * "name": "jesse", * "followers_count": 2 * } * } * ]}
```
This code implements the parser for the above structure:
```
   {@code * * public ListreadJsonStream(BufferedSource source) throws IOException {
 *     JsonReader reader = JsonReader.of(source);
 *     try {
 *       return readMessagesArray(reader);
 *     } finally {
 *       reader.close();
 *     }
 *   }
 *
 *   public List
```
Number HandlingThis reader permits numeric values to be read as strings and string values to be read as numbers. For example, both elements of the JSON array {@code * [1, "1"]} may be read using either nextInt or nextString. This behavior is intended to prevent lossy numeric conversions: double is JavaScript's only numeric type and very large values like {@code * 9007199254740993} cannot be represented exactly on that platform. To minimize precision loss, extremely large values should be written and read as strings in JSON.
Each {@code JsonReader} may be used to read a single JSON stream. Instances of this class are not thread safe.

Nested Class Summary

Nested Classes
Modifier and Type	Class	Description
`public final class`	`JsonReader.Options`	A set of strings to be chosen with selectName. This preparesthe encoded values of the strings so they can be read directly from the input source.
`public enum`	`JsonReader.Token`	A structure, name, or value type in a JSON-encoded string.

Method Summary

Modifier and Type	Method	Description
`static JsonReader`	`of(BufferedSource source)`	Returns a new instance that reads UTF-8 encoded JSON from `{@code source}`.
`abstract void`	`beginArray()`	Consumes the next token from the JSON stream and asserts that it is the beginning of a newarray.
`abstract void`	`endArray()`	Consumes the next token from the JSON stream and asserts that it is theend of the current array.
`abstract void`	`beginObject()`	Consumes the next token from the JSON stream and asserts that it is the beginning of a newobject.
`abstract void`	`endObject()`	Consumes the next token from the JSON stream and asserts that it is the end of the currentobject.
`abstract boolean`	`hasNext()`	Returns true if the current array or object has another element.
`abstract JsonReader.Token`	`peek()`	Returns the type of the next token without consuming it.
`abstract String`	`nextName()`	Returns the next token, a property name, and consumes it.
`abstract int`	`selectName(JsonReader.Options options)`	If the next token is a property name that's in `{@code options}`, thisconsumes it and returns its index.
`abstract void`	`skipName()`	Skips the next token, consuming it.
`abstract String`	`nextString()`	Returns the string value of the next token, consuming it.
`abstract boolean`	`nextBoolean()`	Returns the boolean value of the next token, consuming it.
`abstract double`	`nextDouble()`	Returns the double value of the next token, consuming it.
`abstract int`	`nextInt()`	Returns the int value of the next token, consuming it.
`abstract void`	`skipValue()`	Skips the next value recursively.
`final String`	`getPath()`	Returns a JsonPath tothe current location in the JSON value.

Methods inherited from class java.io.Closeable
close
Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

- Method Detail
  - of
```
 static JsonReader of(BufferedSource source)
```
    Returns a new instance that reads UTF-8 encoded JSON from {@code source}.
  - beginArray
```
 abstract void beginArray()
```
    Consumes the next token from the JSON stream and asserts that it is the beginning of a newarray.
  - endArray
```
 abstract void endArray()
```
    Consumes the next token from the JSON stream and asserts that it is theend of the current array.
  - beginObject
```
 abstract void beginObject()
```
    Consumes the next token from the JSON stream and asserts that it is the beginning of a newobject.
  - endObject
```
 abstract void endObject()
```
    Consumes the next token from the JSON stream and asserts that it is the end of the currentobject.
  - hasNext
```
 abstract boolean hasNext()
```
    Returns true if the current array or object has another element.
  - peek
```
 abstract JsonReader.Token peek()
```
    Returns the type of the next token without consuming it.
  - nextName
```
 abstract String nextName()
```
    Returns the next token, a property name, and consumes it.
  - selectName
```
 abstract int selectName(JsonReader.Options options)
```
    If the next token is a property name that's in {@code options}, thisconsumes it and returns its index. Otherwise this returns -1 and no name is consumed.
  - skipName
```
 abstract void skipName()
```
    Skips the next token, consuming it. This method is intended for use when the JSON token streamcontains unrecognized or unhandled names.
    This throws a JsonDataException if this parser has been configured to fail on unknown names.
  - nextString
```
 abstract String nextString()
```
    Returns the string value of the next token, consuming it. If the nexttoken is a number, this method will return its string form.
  - nextBoolean
```
 abstract boolean nextBoolean()
```
    Returns the boolean value of the next token, consuming it.
  - nextDouble
```
 abstract double nextDouble()
```
    Returns the double value of the next token, consuming it. If the nexttoken is a string, this method will attempt to parse it as a double using .
  - nextInt
```
 abstract int nextInt()
```
    Returns the int value of the next token, consuming it. If the nexttoken is a string, this method will attempt to parse it as an int. If the next token's numericvalue cannot be exactly represented by a Java {@code int}, this method throws.
  - skipValue
```
 abstract void skipValue()
```
    Skips the next value recursively. If it is an object or array, all nested elements are skipped.This method is intended for use when the JSON token stream contains unrecognized or unhandledvalues.
    This throws a JsonDataException if this parser has been configured to fail on unknown values.
  - getPath
```
 final String getPath()
```
    Returns a JsonPath tothe current location in the JSON value.

Class JsonReader

Nested Class Summary

Method Summary

Methods inherited from class java.io.Closeable

Methods inherited from class java.lang.Object

Method Detail

of

beginArray

endArray

beginObject

endObject

hasNext

peek

nextName

selectName

skipName

nextString

nextBoolean

nextDouble

nextInt

skipValue

getPath