How to convert String object to Boolean Object?

How to convert String object to Boolean object?

Try (depending on what result type you want):

Boolean boolean1 = Boolean.valueOf("true");
boolean boolean2 = Boolean.parseBoolean("true");

Advantage:

• Boolean: this does not create new instances of Boolean, so performance is better (and less garbage-collection). It reuses the two instances of either Boolean.TRUE or Boolean.FALSE.
• boolean: no instance is needed, you use the primitive type.

The official documentation is in the Javadoc.

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UPDATED:

Autoboxing could also be used, but it has a performance cost.
I suggest to use it only when you would have to cast yourself, not when the cast is avoidable.

You have to be carefull when using Boolean.valueOf(string) or Boolean.parseBoolean(string). The reason for this is that the methods will always return false if the String is not equal to "true" (the case is ignored).

For example:

Boolean.valueOf("YES") -> false

Because of that behaviour I would recommend to add some mechanism to ensure that the string which should be translated to a Boolean follows a specified format.

For instance:

if (string.equalsIgnoreCase("true") || string.equalsIgnoreCase("false")) {
    Boolean.valueOf(string)
    // do something   
} else {
    // throw some exception
}

Boolean b = Boolean.valueOf(string);

The value of b is true if the string is not a null and equal to true (ignoring case).

Beside the excellent answer of KLE, we can also make something more flexible:

boolean b = string.equalsIgnoreCase("true") || string.equalsIgnoreCase("t") || 
        string.equalsIgnoreCase("yes") || string.equalsIgnoreCase("y") || 
        string.equalsIgnoreCase("sure") || string.equalsIgnoreCase("aye") || 
        string.equalsIgnoreCase("oui") || string.equalsIgnoreCase("vrai");

(inspired by zlajo's answer... :-))

boolean b = string.equalsIgnoreCase("true");

Well, as now in Jan, 2018, the best way for this is to use apache's BooleanUtils.toBoolean.

This will convert any boolean like string to boolean, e.g. Y, yes, true, N, no, false, etc.

Really handy!

Use the Apache Commons library BooleanUtils class:

String[] values= new String[]{"y","Y","n","N","Yes","YES","yes","no","No","NO","true","false","True","False","TRUE","FALSE",null};
for(String booleanStr : values){
    System.out.println("Str ="+ booleanStr +": boolean =" +BooleanUtils.toBoolean(booleanStr));
}

Result:

Str =N: boolean =false
Str =Yes: boolean =true
Str =YES: boolean =true
Str =yes: boolean =true
Str =no: boolean =false
Str =No: boolean =false
Str =NO: boolean =false
Str =true: boolean =true
Str =false: boolean =false
Str =True: boolean =true
Str =False: boolean =false
Str =TRUE: boolean =true
Str =FALSE: boolean =false
Str =null: boolean =false

public static boolean stringToBool(String s) {
        s = s.toLowerCase();
        Set<String> trueSet = new HashSet<String>(Arrays.asList("1", "true", "yes"));
        Set<String> falseSet = new HashSet<String>(Arrays.asList("0", "false", "no"));

        if (trueSet.contains(s))
            return true;
        if (falseSet.contains(s))
            return false;

        throw new IllegalArgumentException(s + " is not a boolean.");
    }

My way to convert string to boolean.

This is how I did it:

"1##true".contains( string )

For my case is mostly either 1 or true. I use hashes as dividers.

Why not use a regular expression ?

public static boolean toBoolean( String target )
{
    if( target == null ) return false;
    return target.matches( "(?i:^(1|true|yes|oui|vrai|y)$)" );
}

We created soyuz-to library to simplify this problem (convert X to Y). It's just a set of SO answers for similar questions. This might be strange to use the library for such a simple problem, but it really helps in a lot of similar cases.

import io.thedocs.soyuz.to;

Boolean aBoolean = to.Boolean("true");

Please check it - it's very simple and has a lot of other useful features

boolean status=false;
if (variable.equalsIgnoreCase("true")) {
   status=true;  
   }

This is supported only if the string is 'true' (not case-sensitive). Later you can play with the status variable.

To get the boolean value of a String, try this:

public boolean toBoolean(String s) {
    try {
        return Boolean.parseBoolean(s); // Successfully converted String to boolean
    } catch(Exception e) {
        return null; // There was some error, so return null.
    }
}

If there is an error, it will return null. Example:

toBoolean("true"); // Returns true
toBoolean("tr.u;e"); // Returns null

Visit <http://msdn.microsoft.com/en-us/library/system.boolean.parse.aspx>

This will give you an idea of what to do.

This is what I get from the Java documentation:

> Method Detail > > parseBoolean > > public static boolean parseBoolean(String s) > > Parses the string argument as a boolean. The boolean returned represents the value true if the string argument is not null and is equal, ignoring case, to the string "true". > > Parameters: > > s - the String containing the boolean representation to be parsed > > Returns: the boolean represented by the string argument > > Since: > 1.5

you can directly set boolean value equivalent to any string by System class and access it anywhere..

System.setProperty("n","false");
System.setProperty("y","true");

System.setProperty("yes","true");     
System.setProperty("no","false");

System.out.println(Boolean.getBoolean("n"));   //false
System.out.println(Boolean.getBoolean("y"));   //true   
 System.out.println(Boolean.getBoolean("no"));  //false
System.out.println(Boolean.getBoolean("yes"));  //true