java Parse Boolean that may be null to Boolean

问题

I noticed an issue with java.lang.Boolean class that it can not parse nulls. I know it has the parseBoolean static method but as it's signature states it only accepts String and not an Object.

In other words, it has the following signature:

public static boolean parseBoolean(String s)

but not:

Boolean.parseBoolean(Object)

What is the best way to check a Boolean value without falling on NullPointerException?

回答1:

Try that approach:

Boolean.TRUE.equals(yourObj);

回答2:

If you want your parse to return true, false or null as a Boolean object, take a look at Apache Commons Lang. BooleanUtils has a one liner that does exactly this.

https://commons.apache.org/proper/commons-lang/javadocs/api-2.4/org/apache/commons/lang/BooleanUtils.html#toBooleanObject(java.lang.String)

BooleanUtils.toBooleanObject(null) == null
BooleanUtils.toBooleanObject("true") == true
BooleanUtils.toBooleanObject("false") == false
BooleanUtils.toBooleanObject("YES") == true
BooleanUtils.toBooleanObject("nO") == false

回答3:

You can compare it to Boolean.TRUE or Boolean.FALSE. Example:

if (Boolean.TRUE == Box.modeled()) { //do somthing }

来源：https://stackoverflow.com/questions/34895627/java-parse-boolean-that-may-be-null-to-boolean