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Java String valueOf() usage and examples

Java String (String) Methods

The Java String valueOf() method returns the string representation of the passed parameter.

The syntax of the valueOf() method for different data types is:

String.valueOf(boolean b)
String.valueOf(char c)
String.valueOf(char[] data)
String.valueOf(double d)
String.valueOf(float f)
String.valueOf(int b)
String.valueOf(long l)
String.valueOf(Object o)

Note:The valueOf() is a static method. We call the valueOf() method using the class name, as shown below: String.valueOf(b);

valueOf() parameters

valueOf() accepts one parameter.

  • Data to be converted to a string

valueOf() return value

  • Returns the string representation of the passed parameter

Example: Java string valueOf() for numbers

class Main {
　　public static void main(String[] args) {
　　　　int a =　5;
　　　　long l =　-2343834L;
　　　　float f =　23.4f;
　　　　double d =　923.234d;
　　　　//Convert numbers to strings
　　　　System.out.println(String.valueOf(a));　　//　"5"
　　　　System.out.println(String.valueOf(l));　　//　"-2343834"
　　　　System.out.println(String.valueOf(f));　　//　"23.4"
　　　　System.out.println(String.valueOf(d));　　//　"923.234"
　　}
}

Example2：Convert char and char array to String

In Java, you can also use+operator to concatenate two strings. For example,

class Main {
　　public static void main(String[] args) {
　　　　char c = 'J';
　　　　char ch[] = {'J', 'a', 'v', 'a'};
　　　　//Convert a char to a string
　　　　System.out.println(String.valueOf(c));　　//　"J"
　　　　//Convert a char array to a string
　　　　System.out.println(String.valueOf(ch));　　//　"Java"
　　}
}

Convert a sub-array of a char array to a String

You can also convert a sub-array of a char array to a string. For this, we use this syntax.

valueOf(char[] data, int offset, int length)

Here,

  • data - Character array

  • offset - Initial offset of the sub-array

  • count - Length of the sub-array

Example3：Convert a sub-array of a char array to a String

class Main {
　　public static void main(String[] args) {
　　　　char ch[] = {'p', 'r', 'o', 'g', 'r', 'a', 'm'};
　　　　int offset =　2;
　　　　int length =　4;
　　　　String result;
　　　　//Convert the sub-array {'o', 'g', 'r', 'm'} to a string
　　　　result = String.valueOf(ch, offset, length);
　　　　System.out.println(result);　　//　"ogrm"
　　}
}

Example4：Convert objects to strings

import java.util.ArrayList;
class Main {
　　public static void main(String[] args) {
　　　　ArrayList<String> languages = new ArrayList<String>();
　　　　languages.add("Java");
　　　　languages.add("Python");
　　　　languages.add("Kotlin");
　　　　String result;
　　　　//　Output: "[Java, Python, Kotlin]"
　　　　result = String.valueOf(languages);
　　　　System.out.println(result);
　　}
}

Here, an ArrayList object (languages) is converted into a string.

In Java, there is another method called copyValueOf(), which is equivalent to the valueOf() method.

Note:You can also use the object.toString() method to convert an object to a string.

Java String (String) Methods

Java Method OverloadingComprehensive Java String Methods