How to convert String to long in Java
String to long
Long
parseLong
valueof
To convert a String to long in Java you have two simple options using the static methods from Long
class:
Long.parseLong(String s)
: returns a primitive long value;Long.valueOf(String s)
: returns an Long object.
Ignoring any of the exceptions that can be thrown, all you need to do to convert a String
to long
is, use on of this lines of code:
long val1 = Long.parseLong(value);
long val2 = Long.valueOf(value);
or
Long obj = Long.valueOf(value);
Note: even if the valueOf method is returning an Long
object you can use the primitive long because the boxing and unboxing will be done automatically.
Example
package com.admfactory;
public class LongConverter {
public static void main(String[] args) {
String value = "100001";
/** Use the value to see the exceptions */
// String value = "number";
try {
long val1 = Long.parseLong(value);
System.out.println("val1: " + val1);
} catch (NumberFormatException e) {
e.printStackTrace();
}
try {
long val2 = Long.valueOf(value);
System.out.println("val2: " + val2);
} catch (NumberFormatException e) {
e.printStackTrace();
}
try {
Long obj = Long.valueOf(value);
System.out.println("obj: " + obj);
} catch (NumberFormatException e) {
e.printStackTrace();
}
}
}
Output
If the value string is a valid long like "1", "2", and so on, it will be converted to a Java primitive long with no problem. The output for this will be:
val1: 100
val2: 100
obj: 100
otherwise, if it fails for any reason, the conversion can throw a NumberFormatException, so to capture and deal with the possible error the code need to be used in try/catch block as shown in the example. The output for this case will be:
java.lang.NumberFormatException: For input string: "number"
at java.lang.NumberFormatException.forInputString(NumberFormatException.java:65)
at java.lang.Long.parseLong(Long.java:441)
at java.lang.Long.parseLong(Long.java:483)
at com.admfactory.xml.LongConverter.main(LongConverter.java:10)