jsonobject.java

JSON使用源码,对于AJAX与服务器数据交换,采用JSON作为数据传输格式是个不错的选择

    /**
     * Get the int value associated with a key. If the number value is too
     * large for an int, it will be clipped.
     *
     * @param key   A key string.
     * @return      The integer value.
     * @throws   JSONException if the key is not found or if the value cannot
     *  be converted to an integer.
     */
    public int getInt(String key) throws JSONException {
        Object o = get(key);
        return o instanceof Number ?
                ((Number)o).intValue() : (int)getDouble(key);
    }


    /**
     * Get the JSONArray value associated with a key.
     *
     * @param key   A key string.
     * @return      A JSONArray which is the value.
     * @throws   JSONException if the key is not found or
     *  if the value is not a JSONArray.
     */
    public JSONArray getJSONArray(String key) throws JSONException {
        Object o = get(key);
        if (o instanceof JSONArray) {
            return (JSONArray)o;
        }
        throw new JSONException("JSONObject[" + quote(key) +
                "] is not a JSONArray.");
    }


    /**
     * Get the JSONObject value associated with a key.
     *
     * @param key   A key string.
     * @return      A JSONObject which is the value.
     * @throws   JSONException if the key is not found or
     *  if the value is not a JSONObject.
     */
    public JSONObject getJSONObject(String key) throws JSONException {
        Object o = get(key);
        if (o instanceof JSONObject) {
            return (JSONObject)o;
        }
        throw new JSONException("JSONObject[" + quote(key) +
                "] is not a JSONObject.");
    }


    /**
     * Get the long value associated with a key. If the number value is too
     * long for a long, it will be clipped.
     *
     * @param key   A key string.
     * @return      The long value.
     * @throws   JSONException if the key is not found or if the value cannot
     *  be converted to a long.
     */
    public long getLong(String key) throws JSONException {
        Object o = get(key);
        return o instanceof Number ?
                ((Number)o).longValue() : (long)getDouble(key);
    }


    /**
     * Get the string associated with a key.
     *
     * @param key   A key string.
     * @return      A string which is the value.
     * @throws   JSONException if the key is not found.
     */
    public String getString(String key) throws JSONException {
        return get(key).toString();
    }


    /**
     * Determine if the JSONObject contains a specific key.
     * @param key   A key string.
     * @return      true if the key exists in the JSONObject.
     */
    public boolean has(String key) {
        return this.myHashMap.containsKey(key);
    }


    /**
     * Determine if the value associated with the key is null or if there is
     *  no value.
     * @param key   A key string.
     * @return      true if there is no value associated with the key or if
     *  the value is the JSONObject.NULL object.
     */
    public boolean isNull(String key) {
        return JSONObject.NULL.equals(opt(key));
    }


    /**
     * Get an enumeration of the keys of the JSONObject.
     *
     * @return An iterator of the keys.
     */
    public Iterator keys() {
        return this.myHashMap.keySet().iterator();
    }


    /**
     * Get the number of keys stored in the JSONObject.
     *
     * @return The number of keys in the JSONObject.
     */
    public int length() {
        return this.myHashMap.size();
    }


    /**
     * Produce a JSONArray containing the names of the elements of this
     * JSONObject.
     * @return A JSONArray containing the key strings, or null if the JSONObject
     * is empty.
     */
    public JSONArray names() {
        JSONArray ja = new JSONArray();
        Iterator  keys = keys();
        while (keys.hasNext()) {
            ja.put(keys.next());
        }
        return ja.length() == 0 ? null : ja;
    }

    /**
     * Produce a string from a Number.
     * @param  n A Number
     * @return A String.
     * @throws JSONException If n is a non-finite number.
     */
    static public String numberToString(Number n)
            throws JSONException {
        if (n == null) {
            throw new JSONException("Null pointer");
        }
        testValidity(n);

// Shave off trailing zeros and decimal point, if possible.

        String s = n.toString();
        if (s.indexOf('.') > 0 && s.indexOf('e') < 0 && s.indexOf('E') < 0) {
            while (s.endsWith("0")) {
                s = s.substring(0, s.length() - 1);
            }
            if (s.endsWith(".")) {
                s = s.substring(0, s.length() - 1);
            }
        }
        return s;
    }


    /**
     * Get an optional value associated with a key.
     * @param key   A key string.
     * @return      An object which is the value, or null if there is no value.
     */
    public Object opt(String key) {
        return key == null ? null : this.myHashMap.get(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".
     *
     * @param key   A key string.
     * @return      The truth.
     */
    public boolean optBoolean(String key) {
        return optBoolean(key, false);
    }


    /**
     * 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).
     *
     * @param key              A key string.
     * @param defaultValue     The default.
     * @return      The truth.
     */
    public boolean optBoolean(String key, boolean defaultValue) {
        try {
            return getBoolean(key);
        } catch (Exception e) {
            return defaultValue;
        }
    }

    
    /**
     * Put a key/value pair in the JSONObject, where the value will be a
     * JSONArray which is produced from a Collection.
     * @param key 	A key string.
     * @param value	A Collection value.
     * @return		this.
     * @throws JSONException
     */
    public JSONObject put(String key, Collection value) throws JSONException {
        put(key, new JSONArray(value));
        return this;
    }

    
    /**
     * 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.
     *
     * @param key   A string which is the key.
     * @return      An object which is the value.
     */
    public double optDouble(String key) {
        return optDouble(key, Double.NaN);
    }


    /**
     * 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.
     *
     * @param key   A key string.
     * @param defaultValue     The default.
     * @return      An object which is the value.
     */
    public double optDouble(String key, double defaultValue) {
        try {
            Object o = opt(key);
            return o instanceof Number ? ((Number)o).doubleValue() :
                new Double((String)o).doubleValue();
        } catch (Exception e) {
            return defaultValue;
        }
    }


    /**
     * 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.
     *
     * @param key   A key string.
     * @return      An object which is the value.
     */
    public int optInt(String key) {
        return optInt(key, 0);
    }


    /**
     * 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.
     *
     * @param key   A key string.
     * @param defaultValue     The default.
     * @return      An object which is the value.
     */
    public int optInt(String key, int defaultValue) {
        try {
            return getInt(key);
        } catch (Exception e) {
            return defaultValue;
        }
    }


    /**
     * 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.
     *
     * @param key   A key string.
     * @return      A JSONArray which is the value.
     */
    public JSONArray optJSONArray(String key) {
        Object o = opt(key);
        return o instanceof JSONArray ? (JSONArray)o : null;
    }


    /**
     * 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.
     *
     * @param key   A key string.
     * @return      A JSONObject which is the value.
     */
    public JSONObject optJSONObject(String key) {
        Object o = opt(key);
        return o instanceof JSONObject ? (JSONObject)o : null;
    }


    /**
     * 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.
     *
     * @param key   A key string.
     * @return      An object which is the value.
     */
    public long optLong(String key) {
        return optLong(key, 0);
    }


    /**
     * 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.
     *
     * @param key   A key string.
     * @param defaultValue     The default.
     * @return      An object which is the value.
     */
    public long optLong(String key, long defaultValue) {
        try {
            return getLong(key);
        } catch (Exception e) {
            return defaultValue;
        }
    }


    /**
     * 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.
     *
     * @param key   A key string.
     * @return      A string which is the value.
     */
    public String optString(String key) {
        return optString(key, "");
    }


    /**
     * Get an optional string associated with a key.
     * It returns the defaultValue if there is no such key.
     *
     * @param key   A key string.
     * @param defaultValue     The default.
     * @return      A string which is the value.
     */
    public String optString(String key, String defaultValue) {
        Object o = opt(key);
        return o != null ? o.toString() : defaultValue;
    }


    /**
     * Put a key/boolean pair in the JSONObject.
     *
     * @param key   A key string.
     * @param value A boolean which is the value.
     * @return this.
     * @throws JSONException If the key is null.
     */
    public JSONObject put(String key, boolean value) throws JSONException {
        put(key, value ? Boolean.TRUE : Boolean.FALSE);
        return this;
    }


    /**
     * Put a key/double pair in the JSONObject.
     *
     * @param key   A key string.
     * @param value A double which is the value.
     * @return this.
     * @throws JSONException If the key is null or if the number is invalid.
     */
    public JSONObject put(String key, double value) throws JSONException {
        put(key, new Double(value));
        return this;
    }


    /**
     * Put a key/int pair in the JSONObject.
     *
     * @param key   A key string.
     * @param value An int which is the value.
     * @return this.
     * @throws JSONException If the key is null.
     */
    public JSONObject put(String key, int value) throws JSONException {
        put(key, new Integer(value));
        return this;
    }


    /**
     * Put a key/long pair in the JSONObject.
     *