java - 为什么 json 以这种奇怪的方式表现？

Question

JSON作为KEY有没有保留字？

我的Json结构是

dimObject{String:String}
finalObject(String:dimObject}

Line1# JSONObject dimObject=new JSONObject()
Line2# dimObject.put("class",["A","B","c"]);
Line3# dimObject.put("name",["sam"]);
Line4# System.out.print("dimObject#"+dimObject.toString());
Line5# JSONObject finalObject=new new JSONObect();
Line6# finalObject("supplier",dimObject);
Line7# System.out.print("finalObject#"+finalObject.toString());

输出:

dimObject#{"class":["A","B","c"],"name":["sam"]}
finalObject#{"supplier":{"name":["sam"]}}

所以问题是为什么我的 json 行为异常。
我没有将“类”定义为变量名，它只是一个键。

问题是，如果给出一个参数，例如，"class"is a key or reserve word then how i successfully inserted in Line#2，如果它在 dimObject 中可以插入 那么为什么它不能在 finalObject 中插入。

请帮我解开这个谜

确切代码::

public JSONObject getRequiredAttributesWithValues() {
        List<UserConstraint> constraintList = new ArrayList<UserConstraint>();
        Map<String, FactTableOptimizingInfo> factTableMap = MappingInfo.INSTANCE.
                getFactTableUserNameToFactTableOptimizingInfoMap();
        Map<String, DimensionTableInfo> dimTableMap = MappingInfo.INSTANCE.getDimTableRealNameToObjectMap();
        JSONObject requiredAttributes = getRequiredAttributes();
        JSONObject finalObject = new JSONObject();
        for (Object dimName : requiredAttributes.keySet()) {
            JSONObject dimObject = new JSONObject();
            JSONArray colNames = requiredAttributes.getJSONArray((String) dimName);
            for (Object colName : colNames) {
                List<String> columnList = new ArrayList<String>();
                String dimensionName = (String) dimName;
                String columnName = (String) colName;
                constraintList = new ArrayList<UserConstraint>();
                for (FilterDataStructure filter : this.info.getGlobalFilterList()) {
                    if (filter.getDimName().equals(dimensionName)) {
                        if (filter.getColumnName().equals(columnName)) {
                            AtomicConstraint.ConstraintType type;
                            try {
                                Integer.parseInt(filter.getValue());
                                type = AtomicConstraint.ConstraintType.INTEGER_TYPE;
                            } catch (NumberFormatException e) {
                                type = AtomicConstraint.ConstraintType.STRING_TYPE;
                            }
                            UserConstraint constraint = new UserAtomicConstraint(dimensionName, columnName, 
                                                        AtomicConstraint.getStringToOperator(filter.getOperator()),
                                                        filter.getValue(), type, factTableMap, dimTableMap);
                            constraintList.add(constraint);
                        }
                    }
                }

                columnList.add(columnName);
                List<UserDimensionInfoToBuildQuery> dimList = new ArrayList<UserDimensionInfoToBuildQuery>();
                UserTableAndColInfo groupByInfo = new UserTableAndColInfo(dimensionName, columnName);
                ArrayList<UserTableAndColInfo> groupByInfoList = new ArrayList<UserTableAndColInfo>();
                groupByInfoList.add(groupByInfo);

                UserDimensionInfoToBuildQuery dim = new UserDimensionInfoToBuildQuery(dimensionName, columnList);
                dimList.add(dim);
                UserInfoToBuildQuery.Builder queryBuilder = new UserInfoToBuildQuery.Builder(dimList).
                        groupBy(groupByInfoList);
                if (constraintList != null && !(constraintList.isEmpty())) {
                    if (constraintList.size() > 1) {
                        queryBuilder = queryBuilder.constraints(new UserComplexConstraint(constraintList,
                                ComplexConstraint.Joiner.AND));
                    } else {
                        queryBuilder = queryBuilder.constraints(constraintList.get(0));
                    }
                }
                List<Object> result = (List<Object>) DataAccessor.getData(queryBuilder.build());
                if (result == null) {
                    continue;
                }
                JSONArray valueArray = new JSONArray();

                for (Object row : result) {
                    List<Object> splitRow = (List<Object>) row;
                    valueArray.add(splitRow.get(0).toString());
                }
                dimObject.put(colName, valueArray);
            }
            finalObject.put(dimName, dimObject);
        }
        return finalObject;
    }
}

Answer 1

根据您的观察，JSON 遵循 JavaScript(或 ECMAScript，应该这样称呼)保留字，class 就是其中之一。

编辑:

在接触javascript时，好像可以在引号内使用保留字，我测试如下:

myObj = {"class" : "Analysis of Algorithms"}; // <--works
myObj = { class  : "Analysis of Algorithms"}; //  <--works
myObj = { class  : "class"}; // <--works
myObj = {"class" :  class }; // <--does not work.

虽然很有趣，但我仍然对这个问题感到困惑。对于 JSON，我将我的所有技术都与 javascript 结合使用，因此我无法产生与您相同的结果。

我找到了 JSONObject.java 的源文件在 this website