README.md

Chapter 3: Strings and Things

Java 11 and 12 added several new String methods, including indent(int n), stripLeading() and stripTrailing(), Stream<T> lines(), isBlank(), and transform().

3.1 Taking Strings Apart with Substrings or Tokenizing

Problem

You want to break a string apart, either by indexing positions or by using fixed token characters (e.g., break on spaces to get words).

Solution

For substrings, use the String object’s substring() method. For tokenizing, construct a StringTokenizer around your string and call its methods hasMoreTokens() and nextToken().

Or, use regular expressions.

3.2 Putting Strings Together with StringBuilder

Problem

You need to put some String pieces (back) together.

Solution

Use string concatenation: the + operator. The compiler implicitly constructs a StringBuilder for you and uses its append() methods (unless all the string parts are known at compile time).

Better yet, construct and use a StringBuilder yourself.

3.3 Processing a String One Character at a Time

Problem

You want to process the contents of a string, one character at a time.

Solution

Use a for loop and the String’s charAt() or codePointAt() method. Or use a “for each” loop and the String’s toCharArray method.

3.5 Converting Between Unicode Characters and Strings

Problem

You want to convert between Unicode characters and Strings.

Solution

Use Java char or String data types to deal with characters; these intrinsically support Unicode. Print characters as integers to display their raw value if needed.