Convert Long to String in Java Convert Long to String in Java

Ashish Lahoti
Java
Page content

In this tutorial, we’ll learn different methods to convert long primitive or Long object to String in Java

Convert long primitive to String

String s1 = Long.toString(1L); // "1"
String s2 = String.valueOf(1L);  // "1"
String s3 = "" + 1L; // "1"

String s4 = new StringBuilder().append(1L).toString(); // "1"
String s5 = String.format("%d", 1L); // "1"
String s6 = new DecimalFormat("#").format(1L); // "1"

We see that first three methods i.e. Long.toString(), String.valueOf, and + are concise and good to use.

Convert Long object to String

Long longObj = 1L;

String s1 = longObj.toString();  // "1"

String s2 = Long.toString(longObj); // "1"
String s3 = String.valueOf(longObj);  // "1"
String s4 = "" + longObj; // "1"

String s5 = new StringBuilder().append(longObj).toString(); // "1"
String s6 = String.format("%d", longObj); // "1"
String s7 = new DecimalFormat("#").format(longObj); // "1"

We see that first method i.e. longObj.toString() is the quickest and concise way to convert a Long object to String, followed by the next three methods.

Exception handling - Long to String

Let’s see how these methods handle the null value:-

Long longObj = null;

String s1 = longObj.toString();  // throw "NullPointerException"
String s2 = Long.toString(longObj); // throw "NullPointerException"
String s3 = String.valueOf(longObj);  // throw "IllegalArgumentException"

String s4 = "" + longObj; // "null"
String s5 = new StringBuilder().append(longObj).toString(); // "null"
String s6 = String.format("%d", longObj); // "null"

String s7 = new DecimalFormat("#").format(longObj); // throw "IllegalArgumentException"

We see that highlighted methods return the “null” string for null value while others throw NullPointerException or IllegalArgumentException so you can use the method wisely.