java正則表達式四種常用的處理方式匹配分割替代獲取？

java中正則表達式處理字符串的四個常用方法：匹配、分割、替換、截取。其跟字符串的常用函數相似，但是使用正則表達式會更簡單、更加簡潔。下面是具體的例子：

1 public class TestRegex {

2

3 public static void main(String[] args) {

4 String str = "";

5 String regex = "";

6

7 // 匹配

8 regex = "[1-9][a-z]";

9 getMatches(str, regex);

10

11 // 分割

12 str = "1a:abc123:";

13 regex = ":";

14 getSpilt(str, regex);

15

16 // 替換

17 str = "1223334444aaabbc";

18 String oldChar = "(.)\1+";

19 regex = "$1";

20 getReplace(str, oldChar, regex);

21

22 // 截取

23 str = "urlabc123";

24 regex = "(.*)";

25 getSubstring(str, regex);

26

27 }

28

29 public static void getMatches(String str, String regex) {

30 System.out.println(str.matches(regex));

31 }

32

33 public static void getSpilt(String str, String regex) {

34 String[] array = str.split(regex);

35 for (String t : array) {

36 System.out.println(t);

37 }

38 }

39

40 public static void getReplace(String str, String oldChar, String regex) {

41 System.out.println(str.replaceAll(oldChar, regex));

42 }

43

44 public static void getSubstring(String str, String regex) {

45 Pattern p = Pattern.compile(regex);

46 Matcher m = p.matcher(str);

47 if (m.find()) {

48 System.out.println(m.group(1));

49 }

50 }

51 }