Java无法识别jSonObject中的空值

Question

I have a jSonObject with key values pairs and i want to parse it to ContentValues. During the parse i want to detect wether the value is null, as you can see in the picture the value is null, but still it does not get catch by the if statement. Because it's a json and might be pasing null as string i tried to use value.equals("null") but neither it worked.

if ( value == null | value. equals("null") || tableField.getType() == FIELD_TYPE_NULL ) {
    DO SOME CODE
}

What's wrong ?

Answer 1

Your first "OR" is just a single pipe '|' instead of the double-pipe '||'

if ( value == null || value.equals("null") || tableField.getType() == FIELD_TYPE_NULL ) {
    DO SOME CODE
}

Answer 2

Try it

if ( value == null || value.equals("null") || tableField.getType() == FIELD_TYPE_NULL ) {
    DO SOME CODE
}

Answer 3

Try using value.isNullObject() function. It returns true if the object is NULL.

Answer 4

if ( value == null | value. equals("null") || tableField.getType() == FIELD_TYPE_NULL ) {
    DO SOME CODE
}

Though in your case if value is "null" above will turn out to be

value == null | value. equals("null")// first condition in if statement --->if(false|true)---> if(true)

you are using bit wise OR not logical OR

It should be

  if ( value == null || value. equals("null") || tableField.getType() == FIELD_TYPE_NULL ) {
        DO SOME CODE
    }

Answer 5

The common way to retrieve values from jsonobject is using getString() method. So you must use value = jsonObject.getString(columnName); to assign the value for value variable. Then you need to check the condition as

if ( value == null || value. equals("null") || tableField.getType() == FIELD_TYPE_NULL ) 
{

}

Answer 6

You're missing one | in you first condition