Create string with the specified number of characters example shows how to create string with n number of characters. The example also shows how to create fixed length string by repeating given character.
How to create a string with the specified number of characters in Java?
There are several ways using which you can create a string with the specified number of characters as given below.
1) Using StringBuilder/StringBuffer
You can use a loop and StringBuilder class to append the specified character number of times to create a fixed length string as given below.
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package com.javacodeexamples.stringexamples; public class StringWithSpecifiedCharsExample { //character to repeat static final String strCharacter = "*"; //required string length static final int stringLength = 10; public static void main(String[] args) { System.out.println(createString()); } public static String createString(){ StringBuilder sbString = new StringBuilder(stringLength); for(int i=0; i < stringLength; i++){ sbString.append(strCharacter); } return sbString.toString(); } } |
Output
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1 |
********** |
Note: If you are using Java 1.4 or earlier versions, use the StringBuffer instead of the StringBuilder class.
2) Using the fill method of Arrays class
Create a char array and fill it with the character you want using fill method of the Arrays class. Finally, convert the character array to a string using the String constructor.
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package com.javacodeexamples.stringexamples; import java.util.Arrays; public class StringWithSpecifiedCharsExample { //character to repeat static final char ch = '*'; //required string length static final int stringLength = 10; public static void main(String[] args) { System.out.println(createString()); } public static String createString(){ //create char array of specified length char[] charArray = new char[stringLength]; //fill all elements with the specified char Arrays.fill(charArray, ch); //create string from char array and return return new String(charArray); } } |
Output
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1 |
********** |
3) Using the replace method of String class
Create a char array of fixed length and create a new String from it using the constructor to get the String of required length. Finally, replace all null characters (represented by ‘\0’) with the character of your choice.
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package com.javacodeexamples.stringexamples; public class StringWithSpecifiedCharsExample { //character to repeat static final char ch = '*'; //required string length static final int stringLength = 10; public static void main(String[] args) { System.out.println(createString()); } public static String createString(){ //create new string from char array of required size String str = new String(new char[stringLength]); //replace all NUL chars '\0' with specified char str = str.replace('\0', ch); return str; } } |
Output
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********** |
4) Using the repeat method of the Apache Commons library
If you are using Apache commons library, you can use repeat method of StringUtils class to create a fixed length string with the specified character.
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public static String repeat(char ch, int n) |
This method creates a new string by repeating specified character n times. You can also use overloaded repeat method that accepts String instead of character.
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package com.javacodeexamples.stringexamples; import org.apache.commons.lang3.StringUtils; public class StringWithSpecifiedCharsExample { //character to repeat static final char ch = '*'; //required string length static final int stringLength = 10; public static void main(String[] args) { String str = StringUtils.repeat(ch, stringLength); System.out.println(str); } } |
Output
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********** |
This example is a part of the Java String tutorial with examples.
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