Handle null values in spring expression language

Question

I have the following code using spring expression language:

StandardEvaluationContext stdContext = new StandardEvaluationContext();
stdContext.setVariable("emp", filterInputData); 
ExpressionParser parser = new SpelExpressionParser();     
parser.parseExpression("#emp.?[name.toLowerCase().contains('Hari')]").getValue(stdContext);

where emp is the name of the bean. Here the name can be null and when calling name.toLowerCase() I am getting a nullpointer exception. How to handle the null values in this scenario? I need to call toLowercase() for only non-null values.

toLowerCase().contains('Hari') is always false

OrangeDog
– OrangeDog

2017-09-19 15:45:35 +00:00
Commented Sep 19, 2017 at 15:45 — OrangeDog
– OrangeDog, Commented Sep 19, 2017 at 15:45

Gary Russell · Accepted Answer · 2012-07-23 12:18:06Z

37

"#emp.name != null ? #emp.name.toLowerCase().contains('hari') : null"

or

"#emp.name != null ? #emp.name.toLowerCase().contains('hari') : false"

depending on what you want back when the name is missing.

Actually, this short form works too...

"#emp.name != null ? toLowerCase().contains('hari') : null"

BTW, in your original question...

name.toLowerCase().contains('Hari')

will never return true (H is upper case).

Or, Elvis is your friend...

Expression expression = new SpelExpressionParser().parseExpression("#emp.name?:'no name found'");
value = expression.getValue(context, String.class).toLowerCase();

answered Jul 23, 2012 at 12:18

Gary Russell

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4 Comments

user1293071 Over a year ago

Hi, Many thanks for your answer. In My case, The employee is a collection of object. So I need to get the name from the collection . I tried with "#emp.?[name != null ? toLowerCase().contains('hari') : null]" , but it is not working and I am getting an message saying that the toLowercase method does not exist in EmployeeDto, Could you please help me to fix this issue. Many thanks

Gary Russell Over a year ago

Not sure why you are trying to use collection selection. If your collection is a map, this works fine... "#emp['name'] != null ? #emp['name'].toLowerCase().contains('hari') : false"

user1293071 Over a year ago

It worked, Many thanks for your support and helping me to find a solution

OrangeDog Over a year ago

It feels like name?.toLowerCase() should also help

Tomer · Accepted Answer · 2012-07-23 11:47:47Z

-1

Can you Autowire this bean to your class?

Something like:

public class YourClass{ 
    @Autowire
    private Employee emp

    public boolean func(){
        if (emp.getName() != null){
            return emp.getName().toLowerCase().contains('Hari');
        }else{
            return false;
        }
    }
}

answered Jul 23, 2012 at 11:47

Tomer

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