Java-反射-转换为JSON数组

Question

i create and set values like the following in java

public Class creatObjectWithDefaultValue(String className) throws IllegalArgumentException, IllegalAccessException {
        DefaultParamValues defaultParamValues = null;
        Class objectClass = null;
        try {
            objectClass = Class.forName(className);
             Field[] fields = objectClass.getClass().getDeclaredFields();

             for(Field f:fields){
                    if(!f.isAccessible()){
                        f.setAccessible(true);
                        Class<?> type = f.getType();

                        if(type.equals(Integer.class)){
                            f.set(objectClass, defaultParamValues.INTEGER);  
                        } else if(type.equals(BigInteger.class)){
                            f.set(objectClass, defaultParamValues.BIGINTEGER);  
                        }else if(type.equals(LocalDate.class)){
                            f.set(objectClass, defaultParamValues.DATE);  
                        }else if(type.equals(Boolean.class)){
                            f.set(objectClass, defaultParamValues.BOOLEAN);  
                        }else if(type.equals(Long.class)){
                            f.set(objectClass, defaultParamValues.LONGVALUE);  
                        }
                        f.setAccessible(false);
                    }
                    //System.out.println(f.get(objectClass));
                }
        } catch (ClassNotFoundException e) {
            e.printStackTrace();
        }
        return objectClass;
    }

now i want to convert the return object as JSON or JSON Array i tried some thing like this but it throws exception as The constructor JSONObject(Class) is undefined

System.out.println ( new JSONObject( te.creatObjectWithDefaultValue("com.hexgen.ro.request.CreateRequisitionRO") ).toString () );

Please help me to correct the mistake.

Best Regards

Answer 1

Why don't you use a Jackson for working with JSON data? Reinventing the wheel is most often error-prone and is only suitable for either education or the case when no library or framework fits your purposes at all.

Now, for JSON <-> Object conversion, there is not a single reason not to use a higher level framework, unless you're explicitly trying to investigate Reflection itself.

Answer 2

there is no constructor with the parameter class in JSONObject.

but you could create an object of the class and pass it to the jsonobject constructor:

System.out.println ( new JSONObject(te.creatObjectWithDefaultValue("com.hexgen.ro.request.CreateRequisitionRO").newInstance() ).toString () );

this only works with classes that have a parameterless constructor

Answer 3

This is very clear.

The constructor JSONObject(Class) is undefined

The API → http://www.json.org/javadoc/org/json/JSONObject.html