How to convert String to Long or Long to String in java with examples

Long, String objects conversion in java

Long is an object which holds larger values. It is a wrapper class in java for primitive type long. if you initialize long values, you need to add l to its value.

The string is a class to represent a group of characters enclosed in double-quotes.

if the string contains non-numeric characters, converting these non-numeric values to long or any numeric data type results in NumberFormatException.

When data is retrieved from the database, the application should display the data either from long to string or string to long.

These are all common requirements in developer coding tasks to cast different java objects.

Both are classes defined in java.lang package.

First, Let’s see different ways we can create a long or string object.

Long l = 78l;  
Long l1 = new Long(3);  
String s=new String("23");  
String s1="21";  

This blog post is about how we can convert Long to String or vice versa.

How to convert Long to String in Java?

There are many ways to convert Long to String in Java.
Let us discuss different ways.

Using toString() method

Every class or object has toString() method.

Long class also has the toString() method that returns the string form of long primitive value.

We can do in two ways using toString method Long.toString(longvalue) method longobject.toString() method

Long l = 1234l;  
System.out.println(l.toString()); // outputs 1234  
System.out.println(Long.toString(l)); // outputs 1234  

using String.valueOf() method

The string class has many static methods. valueOf() is one overloaded method. It returns the value of a long value. T valueOf method has different versions for taking parameters as double, integer and Long pubic static String valueOf(Object value) Object can be of any type

Long longValue=782l;  
System.out.println(String.valueOf(longValue)); //outputs 782  

Using DecimalFormat class

java.text.DecimalFormat class uses to format a long value and convert it into a String. format

Long longObject = 78945l;  
DecimalFormat df = new DecimalFormat("#");  
System.out.println( df.format(longObject));  

output is 78945
Using empty String and append

Any numeric value like integer, long, or double can be converted to a string using the plus operator. The process just creates a string object with an append empty string and numeric value.

Long longObject = 7845l;  
String longString = "" + longObject;  
System.out.println(longString);  

How to Convert String to Long in java?

There are many simple ways to convert it

Using Long constructor

Every Numeric object has a constructor with a string parameter. if a string with non-numeric characters is passed, NumericFormatException will be thrown. character l is also not allowed in the string. only numeric characters allowed

Long longObject=new Long("123");  
System.out.println(longObject);  

using Long.parseLong() method

The long method has many static methods, parseLong is one of the static methods public static long parseLong(String s) throws NumberFormatException .

String str = "1234";  
Long longValue = Long.parseLong(str);  
System.out.println(longValue);  
String str1 = "1234as";  
Long longValue1 = Long.parseLong(str1);  
System.out.println(longValue1);  

output is 1234 java.lang.NumberFormatException: For input string: “1234as” “1234as” string is unable to convert to long and thrown NumberFormatException.

using Long.valueOf(String) method

The long object has a valueOf method, returns a numeric value, and returns a Long object, not primitive type long.

String str = "897";  
Long longValue = Long.valueOf(str);  
System.out.println(longValue);  
String str1 = "87as";  
Long longValue1 = Long.valueOf(str1);  
System.out.println(longValue1);  

That’s on casting long to string or string too long. Please like or share my blog on Facebook/Twitter and also subscribe for the latest posts.