String to int in Java – Convert int to String

The users can use the parseInt() method of the Integer class in order to convert a string to an int in the Java. The valueOf() method of the Integer class can also be used to convert a string to int by returning the instance of the integer class.

# Convert String to int

Scenario

It is normally used when the users have to carry out mathematical operations on the string that includes a number. In the case in which the data is received from the text field or the text area, the data entered is taken in as a string. The string must be converted into an int if the entered data is in the number format. In order to do so, the parseInt() method of the Integer class is used.

Integer.parseInt() method

The parseInt() method is the static operation of the Integer class and the following is the syntax of this operation:

  • public static int parseInt (String s)

# NumberFormatException Case

When there are no numbers in the string literal and the users invoke the parseInt() method of the Integer class or the valueOf() method of the integer class then it throws the number format exception.

# Java convert int to string

The users can use the valueOf() method of the string class and toString() method of the Integer class in order to convert an int to a string in the Java. The format() method of the string class and the string concatenation operator can be alternatively used to do so.

Scenario

It is usually used if the users have to show a number in the text filed because everything is shown as a string in form.

String.valueOf() method

The valueOf() method of the string class is a static method that is used to convert an int to a string. The following is the syntax of this method:

  • public static String valueOf (int i)

Integer toString() method

The toString() method of the Integer class is a static method that is also used to convert an int to a string. The following is the syntax of this method:

  • public static String toString (int i)

String format() method

The format() method of the string class has been introduced since the JDK version 1.5 and is used to format the arguments provided into the string. The following is the syntax of this method:

  • public static String format (String format)

Some popular other methods

# Java String to long

The parseLong() method of the long class is used to convert a string to a long in the Java.

Scenario

It is usually used if the users have to carry out mathematical operations on the string that includes the long number. The data entered is taken in as a string in the case in which the data is received from the text field or the text area. The string needs to be converted into a long if the data entered is long and the parseLong() method of the long class is used to do so.

Long parseLong() method

The parseLong() method of the long class is a static method and the following is the syntax of this method:

  • public static long parseLong (String s)

# Java long to String

The valueOf() method of the string class and the toString() method of the long class can be used in order to convert a long to a string in the Java.

Scenario

It is usually used if the users need to show the long number in the text field in the GUI application because everything is shown as a string in form.

Long toString() method

The toString() method of the long class is a static method that is used to convert a long to a string. The following is the syntax of this method:

  • public static String toString (long i)

# Java string to float

The parseFloat() method of the float class is used in the Java in order to convert a string to a float.

Scenario

It is usually used when the users have to carry out mathematical operations on the string that includes the float number. The data entered is taken in as a string in the case in which the data is received from the text field or the text area. The string needs to be converted into a float if the data entered is a float and the parseFloat() method of the float class is used to do so.

Float parseFloat() method

The parseFloat() method of the float class us a static method and the following is the syntax of this method:

  • public static int parseFloat (String s)

# Java Convert float to String

The valueOf() method of the string class and the toString() method of the float class can be used in the Java in order to convert a float to a string.

Scenario

It is usually used when the users have to show a float value in the text field because everything is shown as a string in form.

Float toString() method

The toString() method of the float class is a static method that is used to convert a float to a string. The following is the syntax of this method:

  • public static String toString (float f)

# Java convert String to double

The parseDouble() method of the double class is used in the Java in order to convert a string to a double.

Scenario

It is usually used when the users have to carry out mathematical operations on the string that includes the double number. The data entered is taken in as a string in the case in which the data is received from the text field or the text area. The string needs to be converted into a double if the data entered is a double and the parseDouble() method of the double class is used to do so.

Double parseDouble() method

The parseDouble() method of the double class is a static method and the following is the syntax of this method:

  • public static double parseDouble (String s)

# Java convert double to string

The valueOf() method of the string class and the toString() method of the double class can be used in order to convert a double to a string in the Java.

Scenario

It is usually used when the users have to show the double value in the text filed for the GUI application because everything is shown as a string in form.

Double toString() method

The toString() method of the double class is a static method that is used to convert a double to a string. The following is the syntax of this method:

  • public static String toString (double d)

# Java String to date

The parse() method of the date format class and the simple date format class can be used in order to convert a string to a date in the Java. This concept has been explained in detail in the date format and the simple date format classes.

Java convert date to String

The format() method of the date format class of the java.text package is used in the Java in order to convert a date into a string.

Date format format() method

The format() method of the date format class is an abstract class that is used to convert a date into a string. The simple date format class is a subclass of the date format class and it is the implementation of the date format class. The following is the syntax of this method:

  • string format (Date d)

# Java convert String to char

The charAt() method of the string class is used to find out a single character of a particular index and to return it. However, it only returns one character so in order to get all the characters, the users need to use the loop. The following is the syntax of this method:

  • public char charAt (int index)

# Java convert char to string

The valueOf() method of the string class and the toString(char) method of the character class can be used in the Java in order to convert a char to a string.

Java convert String to object

The assignment operator is used in the Java in order to convert a string to an object. The users can assign a string to an object directly because all the classes are internally a subclass of the object class.

Java convert Object to String

The toString() method of the object class and the valueOf() method of the string class can be used in the Java in order to convert an object to a string.

The users can convert any object to a string in the Java whether it is a user defined class, a string builder class, a string buffer class, or any other class.

# Java convert int to long

The assignment operator is used in the Java in order to convert an int to a long. Since the lower type can be converted absolutely to a higher type, the users don’t need to do anything extra. This process is also called an implicit type promotion or typecasting.

The valueOf() method of the long class can also be used to convert an int to a long object.

# Java convert long to int

The users must perform typecasting in the Java in order to convert a long to an int. Here, typecasting refers to the process of converting a higher data type into a lower data type.

The intValue() method of the long class can also be used in order to convert a long object to an int.

# Java convert int to double

The assignment operator is used in the Java in order to convert an int to a double. Since the lower type can be converted absolutely to a higher type, the users don’t need to do anything extra. This process is also called implicit type promotion or typecasting.

The valueOf() method of the double class can also be used in order to convert an int to a double.

# Java convert double to int

The users must perform typecasting in the Java in order to convert a double to an int. The typecast operator i.e. datatype is used to carry out the typecasting process in the Java to convert a double type data into an int.

The intValue() method of the double class can also be used in the Java in order to convert a double type data into an int.

# Java convert char into int

There are various methods that can be used in the Java in order to convert a char into an int. if the users assign the char variable to an int directly, then the ASCII value of the character provided will be returned.

The getNumericValue() method of the character class can be used in Java in order to convert a char into an int in the case in which the char variable includes an int value.

Java convert int to char

The users need to use the typecasting process in Java in order to convert an int to char. Typecasting is carried out in the conversion of the higher data type into a lower data type. In this method, the char variable stores the ASCII char of the int value.

The users can add 0 with the integer variable to find out the actual value in the character variable. The forDigit() method of the character class can also be used to do so.

# Java convert String to boolean

The parseBoolean (string) method of the boolean class is used in the Java in order to convert a string to a boolean.

The string must include true to return the boolean true. When the case is ignored, the boolean true will be returned and if there is any other string value except true, then boolean false will be returned.

Boolean parseBoolean() method

The parseBoolean() method of the boolean class is a static method that is used in the Java in order to convert a string into a boolean primitive. The following is the syntax of this method:

  • public static int parseBoolean (String s)

# Java convert boolean to string

The toString() method of the boolean class is a static method that can also be used in the conversion of the boolean to a string. The following is the syntax of this method:

  • public static String toString (boolean b)

# Java convert date to timestamp

The constructor of the timestamp class of the java.sql package is used in the Java in order to convert a date to a timestamp.

The users need to use to the getTime() method of the date class of the java.util package to convert a date into a long value since the constructor of the timestamp class takes in the long value as an arg.

The simple date format class of the java.text package can also be used to format the output of the timestamp.

The following is the syntax of the getTime() method of the date class:

  • public long getTime()

# Java convert timestamp to date

The users need to use the constructor of the date class of the java.util package in the Java in order to convert a timestamp to a date.

The users need to use the getTime() method of the timestamp class of the java.sql package to convert a timestamp object to a long value since the constructor of the date class takes in the long value as an arg.

 public long getTime()

The date class is extended by the timestamp class so the users can directly assign the instance of the time class into a date. In such situations, the date object will return the same output as the timestamp. However, it is not recommended by Java doc to do so as the result may vary in milliseconds or nanoseconds of data.

# Java convert binary to decimal

The parseInt() method of the Integer class or a user-defined logic can be used in the Java in order to convert a binary to a decimal.

Integer parseInt() method

The parseInt() method of the Integer class is used to convert a string to int with the radix provided. The following is the syntax of this method:

  • public static parseInt (String s, int radix)

# Java convert decimal to binary

The toBinaryString() method of the Integer class of a user-defined logic can be used in the Java in order to convert a decimal to a binary.

# Java convert decimal to hexadecimal

The toHexString() method of the Integer class or a user-defined logic can be used in the Java in order to convert a decimal to a hexadecimal.

Integer toHexString() method

The toHexString() method of the Integer class is used to convert a decimal to a hexadecimal and the following is the syntax of this method:

  • public static String toHexString (int decimal)

Java convert octal to decimal

The parseInt() method of the Integer class or a user-defined logic can be used in the Java in order to convert an octal to a decimal.

Integer parseInt() method

The parseInt() method of the Integer class is used to convert a string to int with the radix provided. This method converts an octal string to a decimal in the case in which, 8 has been passed as a radix. The following is the syntax of this method:

  • public static parseInt (String s, int radix)

Java convert decimal to octal

The toOctalString() method of the Integer class or a user-defined logic can be used in the Java in order to convert a decimal to an octal.

Integer toOctalString() method

The toOctalString() method of the Integer class is used to convert a decimal to an octal string and the following is the syntax of this method:

  • public static String toOctalString (int decimal)

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