CODEWITHSUNDEEP
javahashmap
Akeshwar Jha
Akeshwar Jha

Reputation: 4576

JAVA: maps and return type of Map.get

I have a hashmap of key and value both of String type. 

Map<String, String> map = new HashMap<>();
//put the key-values now

I want to check for null or emptiness of the value of a particular key. Referencing the discussion here, I do it as:

if("".equals(map.get("keyName")) {
    //do stuff
}

Is it valid? As the return type of Map.get is Object, so do I need to check it like this:

if("".equals(map.get("keyName").toString()) {
    //do stuff
}

But toString() gives null pointer exception if it is null. So, what is the right way to do it? Yes, I'm a beginner.

Upvotes: 0

Views: 4938

Answers (3)

Sandesh Gupta
Sandesh Gupta

Reputation: 1195

You can use like this -

if(map.get("keyName").equals(null) || map.get("keyName").equals("")){
     //Failed to insert code
}

Upvotes: 0

hotzst
hotzst

Reputation: 7496

I would suggest you use StringUtils from Apache Commons:

if (!StringUtils.isEmpty(map.get("keyName")){
  // Do something
}

See the JavaDoc: https://commons.apache.org/proper/commons-lang/javadocs/api-2.6/org/apache/commons/lang/StringUtils.html#isEmpty%28java.lang.String%29

Upvotes: 0

Adil Shaikh
Adil Shaikh

Reputation: 44740

You can do something like this-

String val = map.get("keyName");
if(val != null && !"".equals(val)){
    // val is not null and is not empty
}

Upvotes: 1

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