天空是蓝色的

//: c12:TestRegularExpression.java
// Allows you to easly try out regular expressions.
// {Args: abcabcabcdefabc "abc+" "(abc)+" "(abc){2,}" }
import java.util.regex.*;
public class TestRegularExpression {
  public static void 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.*;
public class FindDemo {
  private static Test monitor = new Test();
  public static void 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.*;
public class Groups {
  private static Test monitor = new Test();
  static public final 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.";
  public static void main(String[] args) {
    Matcher m =
      Pattern.compile("(?m)(\\S+)\\s+((\\S+)\\s+(\\S+))$")
        .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.*;
public class StartEnd {
  private static Test monitor = new Test();
  public static void 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.*;
public class ReFlags {
  private static Test monitor = new Test();
  public static void 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. !*/
public class TheReplacements {
  private static Test monitor = new Test();
  public static void 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. "
    });
  }
} ///:~

//: c12:ReplacingStringTokenizer.java
import java.util.regex.*;
import com.bruceeckel.simpletest.*;
import java.util.*;
public class ReplacingStringTokenizer {
  private static Test monitor = new Test();
  public static void main(String[] args) {
    String input = "But I'm not dead yet! I feel happy!";
    StringTokenizer stoke = new StringTokenizer(input);
    while(stoke.hasMoreElements())
      System.out.println(stoke.nextToken());
    System.out.println(Arrays.asList(input.split(" ")));
    monitor.expect(new String[] {
      "But",
      "I'm",
      "not",
      "dead",
      "yet!",
      "I",
      "feel",
      "happy!",
      "[But, I'm, not, dead, yet!, I, feel, happy!]"
    });
  }
} ///:~