Class JSONObject

java.lang.Object
org.codehaus.jettison.json.JSONObject
All Implemented Interfaces:
Serializable
public class JSONObject extends Object implements Serializable
A JSONObject is an unordered collection of name/value pairs. Its external form is a string wrapped in curly braces with colons between the names and values, and commas between the values and names. The internal form is an object having get and opt methods for accessing the values by name, and put methods for adding or replacing values by name. The values can be any of these types: Boolean, JSONArray, JSONObject, Number, String, or the JSONObject.NULL object. A JSONObject constructor can be used to convert an external form JSON text into an internal form whose values can be retrieved with the get and opt methods, or to convert values into a JSON text using the put and toString methods. A get method returns a value if one can be found, and throws an exception if one cannot be found. An opt method returns a default value instead of throwing an exception, and so is useful for obtaining optional values.

The generic get() and opt() methods return an object, which you can cast or query for type. There are also typed get and opt methods that do type checking and type coersion for you.

The put methods adds values to an object. For example, 

    myString = new JSONObject().put("JSON", "Hello, World!").toString();
produces the string {"JSON": "Hello, World"}.

The texts produced by the toString methods strictly conform to the JSON sysntax rules. The constructors are more forgiving in the texts they will accept:

  • An extra , (comma) may appear just before the closing brace.
  • Strings may be quoted with ' (single quote).
  • Strings do not need to be quoted at all if they do not begin with a quote or single quote, and if they do not contain leading or trailing spaces, and if they do not contain any of these characters: { } [ ] / \ : , = ; # and if they do not look like numbers and if they are not the reserved words true, false, or null.
  • Keys can be followed by = or => as well as by :.
  • Values can be followed by ; (semicolon) as well as by , (comma).
  • Numbers may have the 0- (octal) or 0x- (hex) prefix.
  • Comments written in the slashshlash, slashstar, and hash conventions will be ignored.
Version:
2
See Also:

  • Field Details

    • DEFAULT_RECURSION_DEPTH_LIMIT

      static final int DEFAULT_RECURSION_DEPTH_LIMIT
      The default recursion depth limit to prevent stack overflow issues on deeply nested structures.
      See Also:

    • RECURSION_DEPTH_LIMIT

      static int RECURSION_DEPTH_LIMIT

    • myHashMap

      private LinkedHashMap<Object,Object> myHashMap
      The hash map where the JSONObject's properties are kept.

    • dropRootElement

      private boolean dropRootElement

    • ignoredElements

      private List ignoredElements

    • writeNullAsString

      private boolean writeNullAsString

    • escapeForwardSlashAlways

      private boolean escapeForwardSlashAlways

    • NULL

      public static final Object NULL
      It is sometimes more convenient and less ambiguous to have a NULL object than to use Java's null value. JSONObject.NULL.equals(null) returns true. JSONObject.NULL.toString() returns "null".

    • EXPLICIT_NULL

      public static final Object EXPLICIT_NULL

  • Constructor Details

    • JSONObject

      public JSONObject()
      Construct an empty JSONObject.

    • JSONObject

      public JSONObject(List ignoredElements)

    • JSONObject

      public JSONObject(boolean dropRootElement, List ignoredElements, boolean writeNullAsString, boolean escapeForwardSlash)

    • JSONObject

      public JSONObject(JSONObject jo, String[] sa) throws JSONException
      Construct a JSONObject from a subset of another JSONObject. An array of strings is used to identify the keys that should be copied. Missing keys are ignored.
      Parameters:
      jo - A JSONObject.
      sa - An array of strings.
      Throws:
      JSONException - If a value is a non-finite number.

    • JSONObject

      public JSONObject(JSONTokener x) throws JSONException
      Construct a JSONObject from a JSONTokener.
      Parameters:
      x - A JSONTokener object containing the source string.
      Throws:
      JSONException - If there is a syntax error in the source string.

    • JSONObject

      public JSONObject(Map map) throws JSONException
      Construct a JSONObject from a Map.
      Parameters:
      map - A map object that can be used to initialize the contents of the JSONObject.
      Throws:
      JSONException - If there is a syntax error.

    • JSONObject

      private JSONObject(Map map, int recursionDepth) throws JSONException
      Throws:
      JSONException

    • JSONObject

      public JSONObject(Object object, String[] names)
      Construct a JSONObject from an Object, using reflection to find the public members. The resulting JSONObject's keys will be the strings from the names array, and the values will be the field values associated with those keys in the object. If a key is not found or not visible, then it will not be copied into the new JSONObject.
      Parameters:
      object - An object that has fields that should be used to make a JSONObject.
      names - An array of strings, the names of the fields to be used from the object.

    • JSONObject

      public JSONObject(String string) throws JSONException
      Construct a JSONObject from a string. This is the most commonly used JSONObject constructor.
      Parameters:
      string - A string beginning with { (left brace) and ending with } (right brace).
      Throws:
      JSONException - If there is a syntax error in the source string.

  • Method Details

    • accumulate

      public JSONObject accumulate(String key, Object value) throws JSONException
      Accumulate values under a key. It is similar to the put method except that if there is already an object stored under the key then a JSONArray is stored under the key to hold all of the accumulated values. If there is already a JSONArray, then the new value is appended to it. In contrast, the put method replaces the previous value.
      Parameters:
      key - A key string.
      value - An object to be accumulated under the key.
      Returns:
      this.
      Throws:
      JSONException - If the value is an invalid number or if the key is null.

    • append

      public JSONObject append(String key, Object value) throws JSONException
      Append values to the array under a key. If the key does not exist in the JSONObject, then the key is put in the JSONObject with its value being a JSONArray containing the value parameter. If the key was already associated with a JSONArray, then the value parameter is appended to it.
      Parameters:
      key - A key string.
      value - An object to be accumulated under the key.
      Returns:
      this.
      Throws:
      JSONException - If the key is null or if the current value associated with the key is not a JSONArray.

    • doubleToString

      public static String doubleToString(double d)
      Produce a string from a double. The string "null" will be returned if the number is not finite.
      Parameters:
      d - A double.
      Returns:
      A String.

    • get

      public Object get(String key) throws JSONException
      Get the value object associated with a key.
      Parameters:
      key - A key string.
      Returns:
      The object associated with the key.
      Throws:
      JSONException - if the key is not found.

    • getBoolean

      public boolean getBoolean(String key) throws JSONException
      Get the boolean value associated with a key.
      Parameters:
      key - A key string.
      Returns:
      The truth.
      Throws:
      JSONException - if the value is not a Boolean or the String "true" or "false".

    • doGetBoolean

      private boolean doGetBoolean(String key, Object o) throws JSONException
      Throws:
      JSONException

    • getDouble

      public double getDouble(String key) throws JSONException
      Get the double value associated with a key.
      Parameters:
      key - A key string.
      Returns:
      The numeric value.
      Throws:
      JSONException - if the key is not found or if the value is not a Number object and cannot be converted to a number.

    • doGetDouble

      private double doGetDouble(String key, Object o) throws JSONException
      Throws:
      JSONException

    • getInt

      public int getInt(String key) throws JSONException
      Get the int value associated with a key. If the number value is too large for an int, it will be clipped.
      Parameters:
      key - A key string.
      Returns:
      The integer value.
      Throws:
      JSONException - if the key is not found or if the value cannot be converted to an integer.

    • doGetInt

      private int doGetInt(String key, Object o) throws JSONException
      Throws:
      JSONException

    • getJSONArray

      public JSONArray getJSONArray(String key) throws JSONException
      Get the JSONArray value associated with a key.
      Parameters:
      key - A key string.
      Returns:
      A JSONArray which is the value.
      Throws:
      JSONException - if the key is not found or if the value is not a JSONArray.

    • getJSONObject

      public JSONObject getJSONObject(String key) throws JSONException
      Get the JSONObject value associated with a key.
      Parameters:
      key - A key string.
      Returns:
      A JSONObject which is the value.
      Throws:
      JSONException - if the key is not found or if the value is not a JSONObject.

    • getLong

      public long getLong(String key) throws JSONException
      Get the long value associated with a key. If the number value is too long for a long, it will be clipped.
      Parameters:
      key - A key string.
      Returns:
      The long value.
      Throws:
      JSONException - if the key is not found or if the value cannot be converted to a long.

    • doGetLong

      private long doGetLong(String key, Object o) throws JSONException
      Throws:
      JSONException

    • getString

      public String getString(String key) throws JSONException
      Get the string associated with a key.
      Parameters:
      key - A key string.
      Returns:
      A string which is the value.
      Throws:
      JSONException - if the key is not found.

    • has

      public boolean has(String key)
      Determine if the JSONObject contains a specific key.
      Parameters:
      key - A key string.
      Returns:
      true if the key exists in the JSONObject.

    • isNull

      public boolean isNull(String key)
      Determine if the value associated with the key is null or if there is no value.
      Parameters:
      key - A key string.
      Returns:
      true if there is no value associated with the key or if the value is the JSONObject.NULL object.

    • keys

      public Iterator keys()
      Get an enumeration of the keys of the JSONObject.
      Returns:
      An iterator of the keys.

    • length

      public int length()
      Get the number of keys stored in the JSONObject.
      Returns:
      The number of keys in the JSONObject.

    • names

      public JSONArray names()
      Produce a JSONArray containing the names of the elements of this JSONObject.
      Returns:
      A JSONArray containing the key strings, or null if the JSONObject is empty.

    • numberToString

      public static String numberToString(Number n) throws JSONException
      Produce a string from a Number.
      Parameters:
      n - A Number
      Returns:
      A String.
      Throws:
      JSONException - If n is a non-finite number.

    • opt

      public Object opt(String key)
      Get an optional value associated with a key.
      Parameters:
      key - A key string.
      Returns:
      An object which is the value, or null if there is no value.

    • optBoolean

      public boolean optBoolean(String key)
      Get an optional boolean associated with a key. It returns false if there is no such key, or if the value is not Boolean.TRUE or the String "true".
      Parameters:
      key - A key string.
      Returns:
      The truth.

    • optBoolean

      public boolean optBoolean(String key, boolean defaultValue)
      Get an optional boolean associated with a key. It returns the defaultValue if there is no such key, or if it is not a Boolean or the String "true" or "false" (case insensitive).
      Parameters:
      key - A key string.
      defaultValue - The default.
      Returns:
      The truth.

    • put

      public JSONObject put(String key, Collection value) throws JSONException
      Put a key/value pair in the JSONObject, where the value will be a JSONArray which is produced from a Collection.
      Parameters:
      key - A key string.
      value - A Collection value.
      Returns:
      this.
      Throws:
      JSONException - JSONException

    • optDouble

      public double optDouble(String key)
      Get an optional double associated with a key, or NaN if there is no such key or if its value is not a number. If the value is a string, an attempt will be made to evaluate it as a number.
      Parameters:
      key - A string which is the key.
      Returns:
      An object which is the value.

    • optDouble

      public double optDouble(String key, double defaultValue)
      Get an optional double associated with a key, or the defaultValue if there is no such key or if its value is not a number. If the value is a string, an attempt will be made to evaluate it as a number.
      Parameters:
      key - A key string.
      defaultValue - The default.
      Returns:
      An object which is the value.

    • optInt

      public int optInt(String key)
      Get an optional int value associated with a key, or zero if there is no such key or if the value is not a number. If the value is a string, an attempt will be made to evaluate it as a number.
      Parameters:
      key - A key string.
      Returns:
      An object which is the value.

    • optInt

      public int optInt(String key, int defaultValue)
      Get an optional int value associated with a key, or the default if there is no such key or if the value is not a number. If the value is a string, an attempt will be made to evaluate it as a number.
      Parameters:
      key - A key string.
      defaultValue - The default.
      Returns:
      An object which is the value.

    • optJSONArray

      public JSONArray optJSONArray(String key)
      Get an optional JSONArray associated with a key. It returns null if there is no such key, or if its value is not a JSONArray.
      Parameters:
      key - A key string.
      Returns:
      A JSONArray which is the value.

    • optJSONObject

      public JSONObject optJSONObject(String key)
      Get an optional JSONObject associated with a key. It returns null if there is no such key, or if its value is not a JSONObject.
      Parameters:
      key - A key string.
      Returns:
      A JSONObject which is the value.

    • optLong

      public long optLong(String key)
      Get an optional long value associated with a key, or zero if there is no such key or if the value is not a number. If the value is a string, an attempt will be made to evaluate it as a number.
      Parameters:
      key - A key string.
      Returns:
      An object which is the value.

    • optLong

      public long optLong(String key, long defaultValue)
      Get an optional long value associated with a key, or the default if there is no such key or if the value is not a number. If the value is a string, an attempt will be made to evaluate it as a number.
      Parameters:
      key - A key string.
      defaultValue - The default.
      Returns:
      An object which is the value.

    • optString

      public String optString(String key)
      Get an optional string associated with a key. It returns an empty string if there is no such key. If the value is not a string and is not null, then it is coverted to a string.
      Parameters:
      key - A key string.
      Returns:
      A string which is the value.

    • optString

      public String optString(String key, String defaultValue)
      Get an optional string associated with a key. It returns the defaultValue if there is no such key.
      Parameters:
      key - A key string.
      defaultValue - The default.
      Returns:
      A string which is the value.

    • put

      public JSONObject put(String key, boolean value) throws JSONException
      Put a key/boolean pair in the JSONObject.
      Parameters:
      key - A key string.
      value - A boolean which is the value.
      Returns:
      this.
      Throws:
      JSONException - If the key is null.

    • put

      public JSONObject put(String key, double value) throws JSONException
      Put a key/double pair in the JSONObject.
      Parameters:
      key - A key string.
      value - A double which is the value.
      Returns:
      this.
      Throws:
      JSONException - If the key is null or if the number is invalid.

    • put

      public JSONObject put(String key, int value) throws JSONException
      Put a key/int pair in the JSONObject.
      Parameters:
      key - A key string.
      value - An int which is the value.
      Returns:
      this.
      Throws:
      JSONException - If the key is null.

    • put

      public JSONObject put(String key, long value) throws JSONException
      Put a key/long pair in the JSONObject.
      Parameters:
      key - A key string.
      value - A long which is the value.
      Returns:
      this.
      Throws:
      JSONException - If the key is null.

    • put

      public JSONObject put(String key, Map value) throws JSONException
      Put a key/value pair in the JSONObject, where the value will be a JSONObject which is produced from a Map.
      Parameters:
      key - A key string.
      value - A Map value.
      Returns:
      this.
      Throws:
      JSONException - JSONException

    • put

      public JSONObject put(String key, Object value) throws JSONException
      Put a key/value pair in the JSONObject. If the value is null, then the key will be removed from the JSONObject if it is present.
      Parameters:
      key - A key string.
      value - An object which is the value. It should be of one of these types: Boolean, Double, Integer, JSONArray, JSONObject, Long, String, or the JSONObject.NULL object.
      Returns:
      this.
      Throws:
      JSONException - If the value is non-finite number or if the key is null.

    • doPut

      protected JSONObject doPut(String key, Object value, int threshold, boolean checkExistingValue) throws JSONException
      Throws:
      JSONException

    • putOpt

      public JSONObject putOpt(String key, Object value) throws JSONException
      Put a key/value pair in the JSONObject, but only if the key and the value are both non-null.
      Parameters:
      key - A key string.
      value - An object which is the value. It should be of one of these types: Boolean, Double, Integer, JSONArray, JSONObject, Long, String, or the JSONObject.NULL object.
      Returns:
      this.
      Throws:
      JSONException - If the value is a non-finite number.

    • quote

      public static String quote(String string)
      Produce a string in double quotes with backslash sequences in all the right places. A backslash will be inserted within </, allowing JSON text to be delivered in HTML. In JSON text, a string cannot contain a control character or an unescaped quote or backslash.
      Parameters:
      string - A String
      Returns:
      A String correctly formatted for insertion in a JSON text.

    • quote

      public static String quote(String string, boolean escapeForwardSlashAlways)

    • remove

      public Object remove(String key)
      Remove a name and its value, if present.
      Parameters:
      key - The name to be removed.
      Returns:
      The value that was associated with the name, or null if there was no value.

    • testValidity

      static void testValidity(Object o) throws JSONException
      Throw an exception if the object is an NaN or infinite number.
      Parameters:
      o - The object to test.
      Throws:
      JSONException - If o is a non-finite number.

    • toJSONArray

      public JSONArray toJSONArray(JSONArray names) throws JSONException
      Produce a JSONArray containing the values of the members of this JSONObject.
      Parameters:
      names - A JSONArray containing a list of key strings. This determines the sequence of the values in the result.
      Returns:
      A JSONArray of values.
      Throws:
      JSONException - If any of the values are non-finite numbers.

    • hashCode

      public int hashCode()
      Overrides:
      hashCode in class Object

    • equals

      public boolean equals(Object obj)
      Overrides:
      equals in class Object

    • toString

      public String toString()
      Make a JSON text of this JSONObject. For compactness, no whitespace is added. If this would not result in a syntactically correct JSON text, then null will be returned instead.

      Warning: This method assumes that the data structure is acyclical.

      Overrides:
      toString in class Object
      Returns:
      a printable, displayable, portable, transmittable representation of the object, beginning with { (left brace) and ending with } (right brace).

    • toString

      public String toString(int indentFactor) throws JSONException
      Make a prettyprinted JSON text of this JSONObject.

      Warning: This method assumes that the data structure is acyclical.

      Parameters:
      indentFactor - The number of spaces to add to each level of indentation.
      Returns:
      a printable, displayable, portable, transmittable representation of the object, beginning with { (left brace) and ending with } (right brace).
      Throws:
      JSONException - If the object contains an invalid number.

    • toString

      String toString(int indentFactor, int indent) throws JSONException
      Make a prettyprinted JSON text of this JSONObject.

      Warning: This method assumes that the data structure is acyclical.

      Parameters:
      indentFactor - The number of spaces to add to each level of indentation.
      indent - The indentation of the top level.
      Returns:
      a printable, displayable, transmittable representation of the object, beginning with { (left brace) and ending with } (right brace).
      Throws:
      JSONException - If the object contains an invalid number.

    • valueToString

      static String valueToString(Object value, boolean escapeForwardSlash) throws JSONException
      Make a JSON text of an Object value. If the object has an value.toJSONString() method, then that method will be used to produce the JSON text. The method is required to produce a strictly conforming text. If the object does not contain a toJSONString method (which is the most common case), then a text will be produced by the rules.

      Warning: This method assumes that the data structure is acyclical.

      Parameters:
      value - The value to be serialized.
      Returns:
      a printable, displayable, transmittable representation of the object, beginning with { (left brace) and ending with } (right brace).
      Throws:
      JSONException - If the value is or contains an invalid number.

    • valueToString

      static String valueToString(Object value, int indentFactor, int indent, boolean escapeForwardSlash) throws JSONException
      Make a prettyprinted JSON text of an object value.

      Warning: This method assumes that the data structure is acyclical.

      Parameters:
      value - The value to be serialized.
      indentFactor - The number of spaces to add to each level of indentation.
      indent - The indentation of the top level.
      Returns:
      a printable, displayable, transmittable representation of the object, beginning with { (left brace) and ending with } (right brace).
      Throws:
      JSONException - If the object contains an invalid number.

    • setGlobalRecursionDepthLimit

      public static void setGlobalRecursionDepthLimit(int newRecursionDepthLimit)
      Set the new recursion depth limit to prevent stack overflow issues on deeply nested structures. The default value is 500
      Parameters:
      newRecursionDepthLimit - the new recursion depth limit to set

    • setRecursionDepthLimit

      @Deprecated public void setRecursionDepthLimit(int newRecursionDepthLimit)
      Deprecated.
      Set the new recursion depth limit to prevent stack overflow issues on deeply nested structures. The default value is 500
      Parameters:
      newRecursionDepthLimit - the new recursion depth limit to set

    • getGlobalRecursionDepthLimit

      public static int getGlobalRecursionDepthLimit()
      Get the new recursion depth limit to prevent stack overflow issues on deeply nested structures. The default value is 500
      Returns:
      the recursion depth limit

    • getRecursionDepthLimit

      @Deprecated public int getRecursionDepthLimit()
      Deprecated.
      Get the new recursion depth limit to prevent stack overflow issues on deeply nested structures. The default value is 500
      Returns:
      the recursion depth limit

    • write

      public Writer write(Writer writer) throws JSONException
      Write the contents of the JSONObject as JSON text to a writer. For compactness, no whitespace is added.

      Warning: This method assumes that the data structure is acyclical.

      Parameters:
      writer - The writer
      Returns:
      The writer.
      Throws:
      JSONException - JSONException

    • isEscapeForwardSlashAlways

      public boolean isEscapeForwardSlashAlways()

    • setEscapeForwardSlashAlways

      public void setEscapeForwardSlashAlways(boolean escapeForwardSlashAlways)

    • toMap

      public Map toMap()