Java正则表达式（超详细）

//: c12:TestRegularExpression.java // Allows you to easly try out regular expressions. // {Args: abcabcabcdefabc "abc+" "(abc)+" "(abc){2,}" } import java.util.regex.*; publicclass TestRegularExpression { publicstaticvoid main(String[] args) { if(args.length < 2) { System.out.println("Usage:/n" + "java TestRegularExpression " + "characterSequence regularExpression+");
System.exit(0);
}
System.out.println("Input: /"" + args[0] + "/""); for(int i = 1; i < args.length; i++) { System.out.println( "Regular expression: /"" + args[i] + "/"");
Pattern p = Pattern.compile(args[i]);
Matcher m = p.matcher(args[0]); while(m.find()) {
System.out.println("Match /"" + m.group() + "/" at positions " +
m.start() + "-" + (m.end() - 1));
}
}
}
} ///:~

//: c12:FindDemo.java import java.util.regex.*; import com.bruceeckel.simpletest.*; import java.util.*; publicclass FindDemo { privatestatic Test monitor = new Test(); publicstaticvoid main(String[] args) {
Matcher m = Pattern.compile("//w+")
.matcher("Evening is full of the linnet's wings"); while(m.find())
System.out.println(m.group()); int i = 0; while(m.find(i)) {
System.out.print(m.group() + " ");
i++;
}
monitor.expect(new String[] { "Evening", "is", "full", "of", "the", "linnet", "s", "wings", "Evening vening ening ning ing ng g is is s full " + "full ull ll l of of f the the he e linnet linnet " + "innet nnet net et t s s wings wings ings ngs gs s " });
}
} ///:~

//: c12:Groups.java import java.util.regex.*; import com.bruceeckel.simpletest.*; publicclass Groups { privatestatic Test monitor = new Test(); staticpublicfinal String poem = "Twas brillig, and the slithy toves/n" + "Did gyre and gimble in the wabe./n" + "All mimsy were the borogoves,/n" + "And the mome raths outgrabe./n/n" + "Beware the Jabberwock, my son,/n" + "The jaws that bite, the claws that catch./n" + "Beware the Jubjub bird, and shun/n" + "The frumious Bandersnatch."; publicstaticvoid main(String[] args) {
Matcher m =
Pattern.compile("(?m)(//S+)//s+((//S+)//s+(//S+))___FCKpd___6quot;)
.matcher(poem); while(m.find()) { for(int j = 0; j <= m.groupCount(); j++) System.out.print("[" + m.group(j) + "]");
System.out.println();
}
monitor.expect(new String[]{ "[the slithy toves]" + "[the][slithy toves][slithy][toves]", "[in the wabe.][in][the wabe.][the][wabe.]", "[were the borogoves,]" + "[were][the borogoves,][the][borogoves,]", "[mome raths outgrabe.]" + "[mome][raths outgrabe.][raths][outgrabe.]", "[Jabberwock, my son,]" + "[Jabberwock,][my son,][my][son,]", "[claws that catch.]" + "[claws][that catch.][that][catch.]", "[bird, and shun][bird,][and shun][and][shun]", "[The frumious Bandersnatch.][The]" + "[frumious Bandersnatch.][frumious][Bandersnatch.]" });
}
} ///:~

//: c12:StartEnd.java import java.util.regex.*; import com.bruceeckel.simpletest.*; publicclass StartEnd { privatestatic Test monitor = new Test(); publicstaticvoid main(String[] args) {
String[] input = new String[] { "Java has regular expressions in 1.4", "regular expressions now expressing in Java", "Java represses oracular expressions" };
Pattern
p1 = Pattern.compile("re//w*"),
p2 = Pattern.compile("Java.*"); for(int i = 0; i < input.length; i++) { System.out.println("input " + i + ": " + input[i]);
Matcher
m1 = p1.matcher(input[i]),
m2 = p2.matcher(input[i]); while(m1.find())
System.out.println("m1.find() '" + m1.group() + "' start = "+ m1.start() + " end = " + m1.end()); while(m2.find())
System.out.println("m2.find() '" + m2.group() + "' start = "+ m2.start() + " end = " + m2.end()); if(m1.lookingAt()) // No reset() necessary System.out.println("m1.lookingAt() start = " + m1.start() + " end = " + m1.end()); if(m2.lookingAt())
System.out.println("m2.lookingAt() start = " + m2.start() + " end = " + m2.end()); if(m1.matches()) // No reset() necessary System.out.println("m1.matches() start = " + m1.start() + " end = " + m1.end()); if(m2.matches())
System.out.println("m2.matches() start = " + m2.start() + " end = " + m2.end());
}
monitor.expect(new String[] { "input 0: Java has regular expressions in 1.4", "m1.find() 'regular' start = 9 end = 16", "m1.find() 'ressions' start = 20 end = 28", "m2.find() 'Java has regular expressions in 1.4'" + " start = 0 end = 35", "m2.lookingAt() start = 0 end = 35", "m2.matches() start = 0 end = 35", "input 1: regular expressions now " + "expressing in Java", "m1.find() 'regular' start = 0 end = 7", "m1.find() 'ressions' start = 11 end = 19", "m1.find() 'ressing' start = 27 end = 34", "m2.find() 'Java' start = 38 end = 42", "m1.lookingAt() start = 0 end = 7", "input 2: Java represses oracular expressions", "m1.find() 'represses' start = 5 end = 14", "m1.find() 'ressions' start = 27 end = 35", "m2.find() 'Java represses oracular expressions' " + "start = 0 end = 35", "m2.lookingAt() start = 0 end = 35", "m2.matches() start = 0 end = 35" });
}
} ///:~

//: c12:ReFlags.java import java.util.regex.*; import com.bruceeckel.simpletest.*; publicclass ReFlags { privatestatic Test monitor = new Test(); publicstaticvoid main(String[] args) {
Pattern p = Pattern.compile("^java",
Pattern.CASE_INSENSITIVE | Pattern.MULTILINE);
Matcher m = p.matcher( "java has regex/nJava has regex/n" + "JAVA has pretty good regular expressions/n" + "Regular expressions are in Java"); while(m.find())
System.out.println(m.group());
monitor.expect(new String[] { "java", "Java", "JAVA" });
}
} ///:~

//: c12:TheReplacements.java import java.util.regex.*; import java.io.*; import com.bruceeckel.util.*; import com.bruceeckel.simpletest.*; /*! Here's a block of text to use as input to
the regular expression matcher. Note that we'll
first extract the block of text by looking for
the special delimiters, then process the
extracted block. !*/ publicclass TheReplacements { privatestatic Test monitor = new Test(); publicstaticvoid main(String[] args) throws Exception {
String s = TextFile.read("TheReplacements.java"); // Match the specially-commented block of text above: Matcher mInput =
Pattern.compile("///*!(.*)!//*/", Pattern.DOTALL)
.matcher(s); if(mInput.find())
s = mInput.group(1); // Captured by parentheses // Replace two or more spaces with a single space: s = s.replaceAll(" {2,}", " "); // Replace one or more spaces at the beginning of each // line with no spaces. Must enable MULTILINE mode: s = s.replaceAll("(?m)^ +", "");
System.out.println(s);
s = s.replaceFirst("[aeiou]", "(VOWEL1)");
StringBuffer sbuf = new StringBuffer();
Pattern p = Pattern.compile("[aeiou]");
Matcher m = p.matcher(s); // Process the find information as you // perform the replacements: while(m.find())
m.appendReplacement(sbuf, m.group().toUpperCase()); // Put in the remainder of the text: m.appendTail(sbuf);
System.out.println(sbuf);
monitor.expect(new String[]{ "Here's a block of text to use as input to", "the regular expression matcher. Note that we'll", "first extract the block of text by looking for", "the special delimiters, then process the", "extracted block. ", "H(VOWEL1)rE's A blOck Of tExt tO UsE As InpUt tO", "thE rEgUlAr ExprEssIOn mAtchEr. NOtE thAt wE'll", "fIrst ExtrAct thE blOck Of tExt by lOOkIng fOr", "thE spEcIAl dElImItErs, thEn prOcEss thE", "ExtrActEd blOck. " });
}
} ///:~