Class JSONTokener
- java.lang.Object
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- org.json.JSONTokener
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public class JSONTokener extends java.lang.Object
Parses a JSON (RFC 4627) encoded string into the corresponding object. Most clients of this class will use only need theconstructor
andnextValue()
method. Example usage:String json = "{" + " \"query\": \"Pizza\", " + " \"locations\": [ 94043, 90210 ] " + "}"; JSONObject object = (JSONObject) new JSONTokener(json).nextValue(); String query = object.getString("query"); JSONArray locations = object.getJSONArray("locations");
For best interoperability and performance use JSON that complies with RFC 4627, such as that generated by
JSONStringer
. For legacy reasons this parser is lenient, so a successful parse does not indicate that the input string was valid JSON. All of the following syntax errors will be ignored:- End of line comments starting with
//
or#
and ending with a newline character. - C-style comments starting with
/*
and ending with*
/
. Such comments may not be nested. - Strings that are unquoted or
'single quoted'
. - Hexadecimal integers prefixed with
0x
or0X
. - Octal integers prefixed with
0
. - Array elements separated by
;
. - Unnecessary array separators. These are interpreted as if null was the omitted value.
- Key-value pairs separated by
=
or=>
. - Key-value pairs separated by
;
.
Each tokener may be used to parse a single JSON string. 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.
- End of line comments starting with
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Constructor Summary
Constructors Constructor Description JSONTokener(java.lang.String in)
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Method Summary
All Methods Static Methods Instance Methods Concrete Methods Modifier and Type Method Description void
back()
Unreads the most recent character of input.static int
dehexchar(char hex)
Returns the integer [0..15] value for the given hex character, or -1 for non-hex input.boolean
more()
Returns true until the input has been exhausted.char
next()
Returns the next available character, or the null character '\0' if all input has been exhausted.char
next(char c)
Returns the next available character if it equalsc
.java.lang.String
next(int length)
Returns the nextlength
characters of the input.char
nextClean()
Returns the next character that is not whitespace and does not belong to a comment.java.lang.String
nextString(char quote)
Returns the string up to but not includingquote
, unescaping any character escape sequences encountered along the way.java.lang.String
nextTo(char excluded)
Equivalent tonextTo(String.valueOf(excluded))
.java.lang.String
nextTo(java.lang.String excluded)
Returns thetrimmed
string holding the characters up to but not including the first of: any character inexcluded
a newline character '\n' a carriage return '\r'java.lang.Object
nextValue()
Returns the next value from the input.void
skipPast(java.lang.String thru)
Advances past all input up to and including the next occurrence ofthru
.char
skipTo(char to)
Advances past all input up to but not including the next occurrence ofto
.JSONException
syntaxError(java.lang.String message)
Returns an exception containing the given message plus the current position and the entire input string.java.lang.String
toString()
Returns the current position and the entire input string.
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Method Detail
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nextValue
public java.lang.Object nextValue() throws JSONException
Returns the next value from the input.- Returns:
- a
JSONObject
,JSONArray
, String, Boolean, Integer, Long, Double orJSONObject.NULL
. - Throws:
JSONException
- if the input is malformed.
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nextString
public java.lang.String nextString(char quote) throws JSONException
Returns the string up to but not includingquote
, unescaping any character escape sequences encountered along the way. The opening quote should have already been read. This consumes the closing quote, but does not include it in the returned string.- Parameters:
quote
- either ' or ".- Throws:
JSONException
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syntaxError
public JSONException syntaxError(java.lang.String message)
Returns an exception containing the given message plus the current position and the entire input string.
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toString
public java.lang.String toString()
Returns the current position and the entire input string.- Overrides:
toString
in classjava.lang.Object
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more
public boolean more()
Returns true until the input has been exhausted.
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next
public char next()
Returns the next available character, or the null character '\0' if all input has been exhausted. The return value of this method is ambiguous for JSON strings that contain the character '\0'.
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next
public char next(char c) throws JSONException
Returns the next available character if it equalsc
. Otherwise an exception is thrown.- Throws:
JSONException
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nextClean
public char nextClean() throws JSONException
Returns the next character that is not whitespace and does not belong to a comment. If the input is exhausted before such a character can be found, the null character '\0' is returned. The return value of this method is ambiguous for JSON strings that contain the character '\0'.- Throws:
JSONException
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next
public java.lang.String next(int length) throws JSONException
Returns the nextlength
characters of the input.The returned string shares its backing character array with this tokener's input string. If a reference to the returned string may be held indefinitely, you should use
new String(result)
to copy it first to avoid memory leaks.- Throws:
JSONException
- if the remaining input is not long enough to satisfy this request.
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nextTo
public java.lang.String nextTo(java.lang.String excluded)
Returns thetrimmed
string holding the characters up to but not including the first of:- any character in
excluded
- a newline character '\n'
- a carriage return '\r'
The returned string shares its backing character array with this tokener's input string. If a reference to the returned string may be held indefinitely, you should use
new String(result)
to copy it first to avoid memory leaks.- Returns:
- a possibly-empty string
- any character in
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nextTo
public java.lang.String nextTo(char excluded)
Equivalent tonextTo(String.valueOf(excluded))
.
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skipPast
public void skipPast(java.lang.String thru)
Advances past all input up to and including the next occurrence ofthru
. If the remaining input doesn't containthru
, the input is exhausted.
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skipTo
public char skipTo(char to)
Advances past all input up to but not including the next occurrence ofto
. If the remaining input doesn't containto
, the input is unchanged.
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back
public void back()
Unreads the most recent character of input. If no input characters have been read, the input is unchanged.
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dehexchar
public static int dehexchar(char hex)
Returns the integer [0..15] value for the given hex character, or -1 for non-hex input.- Parameters:
hex
- a character in the ranges [0-9], [A-F] or [a-f]. Any other character will yield a -1 result.
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