Limiting the number of characters in a string, and chopping off the rest

You can use the Apache Commons StringUtils.substring(String str, int start, int end) static method, which is also null safe.

See: http://commons.apache.org/proper/commons-lang/javadocs/api-2.6/org/apache/commons/lang/StringUtils.html#substring%28java.lang.String,%20int,%20int%29

and http://commons.apache.org/proper/commons-lang/javadocs/api-2.6/src-html/org/apache/commons/lang/StringUtils.html#line.1961

For readability, I prefer this:

if (inputString.length() > maxLength) {
    inputString = inputString.substring(0, maxLength);
}

over the accepted answer.

int maxLength = (inputString.length() < MAX_CHAR)?inputString.length():MAX_CHAR;
inputString = inputString.substring(0, maxLength);

You can also use String.format("%3.3s", "abcdefgh"). The first digit is the minimum length (the string will be left padded if it's shorter), the second digit is the maxiumum length and the string will be truncated if it's longer. So

System.out.printf("'%3.3s' '%3.3s'", "abcdefgh", "a");

will produce

'abc' '  a'

(you can remove quotes, obviously).

Use this to cut off the non needed characters:

String.substring(0, maxLength); 

Example:

String aString ="123456789";
String cutString = aString.substring(0, 4);
// Output is: "1234" 

To ensure you are not getting an IndexOutOfBoundsException when the input string is less than the expected length do the following instead:

int maxLength = (inputString.length() < MAX_CHAR)?inputString.length():MAX_CHAR;
inputString = inputString.substring(0, maxLength);

If you want your integers and doubles to have a certain length then I suggest you use NumberFormat to format your numbers instead of cutting off their string representation.