Use StringUtils.substringBetween( ). This method
will return a string surrounded by two strings, which are supplied as
parameters. The following example demonstrates the use of this method
to extract content from HTML:
String htmlContent = "<html>
" +
" <head>
" +
" <title>Test Page</title>
" +
" </head>
" +
" <body>
" +
" <p>This is a TEST!</p>
" +
" </body>
" +
"</html>";
// Extract the title from this XHTML content
String title = StringUtils.substringBetween(htmlContent, "<title>",
"</title>");
System.out.println( "Title: " + title );This code extracts the title from this HTML document and prints the following:
Title: Test Page
In the Solution section, the substringBetween()
method returns the first string between the
open and close
strings—the title of an HTML document. The previous example
only contained one nested element, but what happens when a string
contains multiple elements nested in the same two strings? In the
following example, three variables are extracted from a string using
substringBetween( ):
String variables = "{45}, {35}, {120}" ;
List numbers = new ArrayList( );
String variablesTemp = variables;
while( StringUtils.substringBetween( variablesTemp, "{", "}" ) != null ) {
String numberStr = StringUtils.substringBetween( variables, "{", "}" );
Double number = new Double( numberStr );
numbers.add( number );
variablesTemp = variablesTemp.substring( variablesTemp.indexOf(",") );
}
double sum = StatUtil.sum( ArrayUtils.toPrimitive( numbers.toArray( ) ) );
System.out.println( "Variables: " + variables + ", Sum: " + sum );The output of this example is:
Variable: {45}, {35}, {120}, Sum: 200After each number is extracted from the curly braces, the system
finds the index of the next comma and reduces the size of the string
to search for the next call to StringUtils.
StringUtils.substringBetween( ) can also find text
that is delimited by the same character:
String message = "|TESTING| BOUNDARYExampleBOUNDARY"; String first = StringUtils.substringBetween( message, "|"); String second = StringUtils.substringBetween( message, "BOUNDARY");
The first string would return
“TESTING” as it is between the
| characters, and the second string would contain
“Example.”