Java正则表达式(2)

Java正则表达式(二)

Matcher类:引用\w(\d\d)(\w+)

这个正则表达式有三个组:Java代码

1. package?edu.jlu.fuliang;??
2. ??
3. import?java.util.regex.Matcher;??
4. import?java.util.regex.Pattern;??
5. ??
6. ??
7. public?class?RegexTest?{??
8. ????public?static?void?main(String[]?args)?{??
9. ????????String?regex?=?"\\w(\\d\\d)(\\w+)";??
10. ????????String?candidate?=?"x99SuperJava";??
11. ??????????
12. ????????Pattern?p?=?Pattern.compile(regex);??
13. ????????Matcher?matcher?=?p.matcher(candidate);??
14. ????????if(matcher.find()){??
15. ????????????int?gc?=?matcher.groupCount();??
16. ????????????for(int?i?=?0;?i?<=?gc;?i++)??
17. ????????????????System.out.println("group?"?+?i?+?"?:"?+?matcher.group(i));??
18. ????????}??
19. ????}??
20. }??

输出结果:引用group 099SuperJavaJava代码

1. import?java.util.regex.*;??
2. ??
3. public?class?MatcherPatternExample{??
4. ??public?static?void?main(String?args[]){??
5. ??????test();??
6. ??}??
7. ??
8. ??public?static?void?test(){??
9. ?????Pattern?p?=?Pattern.compile("\\d");??
10. ?????Matcher?m1?=?p.matcher("55");??
11. ?????Matcher?m2?=?p.matcher("fdshfdgdfh");??
12. ??
13. ?????System.out.println(m1.pattern()?==?m2.pattern());??
14. ?????//return?true??
15. ??}??
16. }??

public Matcher reset()Java代码

1. public?class?MatcherStartExample{??
2. ??public?static?void?main(String?args[]){??
3. ??????test();??
4. ??}??
5. ??public?static?void?test(){??
6. ?????//create?a?Matcher?and?use?the?Matcher.start()?method??
7. ?????String?candidateString?=?"My?name?is?Bond.?James?Bond.";??
8. ?????String?matchHelper[]?=??
9. ??????{"??????????^","??????????????????????^"};??
10. ?????Pattern?p?=?Pattern.compile("Bond");??
11. ?????Matcher?matcher?=?p.matcher(candidateString);??
12. ??
13. ?????//Find?the?starting?point?of?the?first?'Bond'??
14. ??????matcher.find();??
15. ??????int?startIndex?=?matcher.start();??
16. ??????System.out.println(candidateString);??
17. ??????System.out.println(matchHelper[0]?+?startIndex);??
18. ??
19. ?????//Find?the?starting?point?of?the?second?'Bond'??
20. ??????matcher.find();??
21. ??????int?nextIndex?=?matcher.start();??
22. ??????System.out.println(candidateString);??
23. ??????System.out.println(matchHelper[1]?+?nextIndex);??
24. }??

输出结果：Java代码

1. import?java.util.regex.*;??
2. ??
3. public?class?MatcherGroupExample{??
4. ??public?static?void?main(String?args[]){??
5. ??????test();??
6. ??}??
7. ??public?static?void?test(){??
8. ??????//create?a?Pattern??
9. ??????Pattern?p?=?Pattern.compile("Bond");??
10. ??
11. ??????//create?a?Matcher?and?use?the?Matcher.group()?method??
12. ??????String?candidateString?=?"My?name?is?Bond.?James?Bond.";??
13. ??????Matcher?matcher?=?p.matcher(candidateString);??
14. ??????//extract?the?group??
15. ??????matcher.find();??
16. ??????System.out.println(matcher.group());??
17. ??}??
18. }??

public String group(int group)Java代码

1. import?java.util.regex.*;??
2. ??
3. public?class?MatcherGroupParamExample{??
4. ??public?static?void?main(String?args[]){??
5. ??????test();??
6. ??}??
7. ??public?static?void?test(){??
8. ?????//create?a?Pattern??
9. ??????Pattern?p?=?Pattern.compile("B(ond)");??
10. ??
11. ?????//create?a?Matcher?and?use?the?Matcher.group(int)?method??
12. ?????String?candidateString?=?"My?name?is?Bond.?James?Bond.";??
13. ?????//create?a?helpful?index?for?the?sake?of?output??
14. ?????Matcher?matcher?=?p.matcher(candidateString);??
15. ?????//Find?group?number?0?of?the?first?find??
16. ??????matcher.find();??
17. ??????String?group_0?=?matcher.group(0);??
18. ??????String?group_1?=?matcher.group(1);??
19. ??????System.out.println("Group?0?"?+?group_0);??
20. ??????System.out.println("Group?1?"?+?group_1);??
21. ??????System.out.println(candidateString);??
22. ??
23. ?????//Find?group?number?1?of?the?second?find??
24. ??????matcher.find();??
25. ??????group_0?=?matcher.group(0);??
26. ??????group_1?=?matcher.group(1);??
27. ??????System.out.println("Group?0?"?+?group_0);??
28. ??????System.out.println("Group?1?"?+?group_1);??
29. ??????System.out.println(candidateString);??
30. ??}??
31. }??

public int groupCount()Java代码

1. while(matcher.find()){??
2. ???//在匹配的区域，使用group,replace等进行查看和替换操作??
3. }??

public boolean find(int start)Java代码

1. StringBuffer?sb?=?new?StringBuffer();??
2. String?replacement?=?"Smith";??
3. Pattern?pattern?=?Pattern.compile("Bond");??
4. Matcher?matcher?=pattern.matcher("My?name?is?Bond.?James?Bond.?I?would?like?a?martini.");??
5. while(matcher.find()){??
6. ??matcher.appendReplacement(sb,replacement);//结果是My?name?is?Smith.?James?Smith??
7. }??

Matcher对象会维护追加的位置，所以我们才能不断地使用appendReplacement来替换所有的匹配。Java代码

1. while(matcher.find()){??
2. ??matcher.appendReplacement(sb,replacement);//结果是My?name?is?Smith.?James?Smith??
3. }??
4. matcher.appendTail(sb);??

的更便捷的方法。Java代码

1. public?String?replaceFirst(String?replacement)??

这个与replaceAll想对应很容易理解，就是只替换第一个匹配的。

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转载自：http://fuliang.iteye.com/blog/175035

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