jsonobject.java

很好的json数据处理格式

        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.
     *
     * @param key   A key string.
     * @param value A long which is the value.
     * @return this.
     * @throws JSONException If the key is null.
     */
    public JSONObject put(String key, long value) throws JSONException {
        put(key, new Long(value));
        return this;
    }


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


    /**
     * 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.
     * @param key   A key string.
     * @param 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.
     * @return this.
     * @throws JSONException If the value is non-finite number
     *  or if the key is null.
     */
    public JSONObject put(String key, Object value) throws JSONException {
        if (key == null) {
            throw new JSONException("Null key.");
        }
        if (value != null) {
            testValidity(value);
            this.map.put(key, value);
        } else {
            remove(key);
        }
        return this;
    }


    /**
     * Put a key/value pair in the JSONObject, but only if the key and the 
     * value are both non-null, and only if there is not already a member 
     * with that name.
     * @param key
     * @param value
     * @return his.
     * @throws JSONException if the key is a duplicate
     */
    public JSONObject putOnce(String key, Object value) throws JSONException {
        if (key != null && value != null) {
        	if (opt(key) != null) {
                throw new JSONException("Duplicate key \"" + key + "\"");
        	}
            put(key, value);
        }
        return this;
    }


    /**
     * Put a key/value pair in the JSONObject, but only if the
     * key and the value are both non-null.
     * @param key   A key string.
     * @param 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.
     * @return this.
     * @throws JSONException If the value is a non-finite number.
     */
    public JSONObject putOpt(String key, Object value) throws JSONException {
        if (key != null && value != null) {
            put(key, value);
        }
        return this;
    }
    
    
    /**
     * 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.
     * @param string A String
     * @return  A String correctly formatted for insertion in a JSON text.
     */
    public static String quote(String string) {
        if (string == null || string.length() == 0) {
            return "\"\"";
        }

        char         b;
        char         c = 0;
        int          i;
        int          len = string.length();
        StringBuffer sb = new StringBuffer(len + 4);
        String       t;

        sb.append('"');
        for (i = 0; i < len; i += 1) {
            b = c;
            c = string.charAt(i);
            switch (c) {
            case '\\':
            case '"':
                sb.append('\\');
                sb.append(c);
                break;
            case '/':
                if (b == '<') {
                    sb.append('\\');
                }
                sb.append(c);
                break;
            case '\b':
                sb.append("\\b");
                break;
            case '\t':
                sb.append("\\t");
                break;
            case '\n':
                sb.append("\\n");
                break;
            case '\f':
                sb.append("\\f");
                break;
            case '\r':
                sb.append("\\r");
                break;
            default:
                if (c < ' ' || (c >= '\u0080' && c < '\u00a0') ||
                               (c >= '\u2000' && c < '\u2100')) {
                    t = "000" + Integer.toHexString(c);
                    sb.append("\\u" + t.substring(t.length() - 4));
                } else {
                    sb.append(c);
                }
            }
        }
        sb.append('"');
        return sb.toString();