我一直在涉猎JSON,发现在文档中(JAVA),JSONObject的put()和accumulate()几乎是相同的操作?
这是怎么回事?
我一直在涉猎JSON,发现在文档中(JAVA),JSONObject的put()和accumulate()几乎是相同的操作?
这是怎么回事?
我看到了 JSONObject 的 Java 源代码,accumulate 和 put 的区别在于:使用 accumulate(String key,Object Value) 方法时,如果存在 "key" 的某个值,则会检查该对象是否为数组,如果是,则将 "value" 添加到该数组中,否则将为此键创建一个数组。
但是,在使用 put 方法时,如果存在该键,则其值将被替换为指定的值。
下面是 JSONObject accumulate(String key, Object Value) 的源代码:
/**
* Appends {@code value} to the array already mapped to {@code name}. If
* this object has no mapping for {@code name}, this inserts a new mapping.
* If the mapping exists but its value is not an array, the existing
* and new values are inserted in order into a new array which is itself
* mapped to {@code name}. In aggregate, this allows values to be added to a
* mapping one at a time.
*
* <p> Note that {@code append(String, Object)} provides better semantics.
* In particular, the mapping for {@code name} will <b>always</b> be a
* {@link JSONArray}. Using {@code accumulate} will result in either a
* {@link JSONArray} or a mapping whose type is the type of {@code value}
* depending on the number of calls to it.
*
* @param value a {@link JSONObject}, {@link JSONArray}, String, Boolean,
* Integer, Long, Double, {@link #NULL} or null. May not be {@link
* Double#isNaN() NaNs} or {@link Double#isInfinite() infinities}.
*/
public JSONObject accumulate(String name, Object value) throws JSONException {
Object current = nameValuePairs.get(checkName(name));
if (current == null) {
return put(name, value);
}
if (current instanceof JSONArray) {
JSONArray array = (JSONArray) current;
array.checkedPut(value);
} else {
JSONArray array = new JSONArray();
array.checkedPut(current);
array.checkedPut(value);
nameValuePairs.put(name, array);
}
return this;
}
这里是JSONObject put (String key, Object value)的代码
/**
* Maps {@code name} to {@code value}, clobbering any existing name/value
* mapping with the same name.
*
* @return this object.
*/
public JSONObject put(String name, boolean value) throws JSONException {
nameValuePairs.put(checkName(name), value);
return this;
}