Java正则表达式中的捕获组的概念及相关API使用

package pattern;import java.util.regex.Matcher;
import java.util.regex.Pattern;public class testRegex {
public static void main(String[] args) {
String regex = "(x)(y\\w*)(z)"; String input = "exy123z,xy456z";
Pattern p = Pattern.compile(regex, Pattern.CASE_INSENSITIVE);
Matcher m = p.matcher(input); while (m.find()) {
System.out.println(m.group(2));
}
}
}

import java.util.regex.Matcher;
import java.util.regex.Pattern;/*2015-9-9*/
public class RegexDemo {
public static void main(String[] args) {
String regex = "(T_V)([\\d])|(xx)+";
String source = "T_V123,TX_V1,T_V234";
Pattern pattern = Pattern.compile(regex);
Matcher matcher = pattern.matcher(source);
System.out.println("是否匹配:"+matcher.matches());
if (matcher.find()) {
for (int i = 0; i <= matcher.groupCount(); i++) {
String group = matcher.group(i);
System.out.println("number " + i + ":" + group+"; Is null:"+(group==null));
}
}
}}

是否匹配:false
number 0:T_V1; Is null:false
number 1:T_V; Is null:false
number 2:1; Is null:false
number 3:null; Is null:true

public boolean matches()
Attempts to match the entire region against the pattern.
If the match succeeds then more information can be obtained via the start, end, and group methods.
Returns:
true if, and only if, the entire region sequence matches this matcher's pattern注：
matches
public boolean matches()
尝试将整个区域与模式匹配。
如果匹配成功，则可以通过 start、end 和 group 方法获取更多信息。
返回：
当且仅当整个区域序列匹配此匹配器的模式时才返回 true。

public boolean find()
Attempts to find the next subsequence of the input sequence that matches the pattern.
This method starts at the beginning of this matcher's region, or,
if a previous invocation of the method was successful and the matcher has not since been reset,
at the first character not matched by the previous match.
If the match succeeds then more information can be obtained via the start, end, and group methods.
Returns:
true if, and only if, a subsequence of the input sequence matches this matcher's pattern
注：
find
public boolean find()
尝试查找与该模式匹配的输入序列的下一个子序列。
此方法从匹配器区域的开头开始，如果该方法的前一次调用成功了并且从那时开始匹配器没有被重置，则从以前匹配操作没有匹配的第一个字符开始。
如果匹配成功，则可以通过 start、end 和 group 方法获取更多信息。
返回：
当且仅当输入序列的子序列匹配此匹配器的模式时才返回 true。

public class StringRegexDemo {
public static void main(String[] args) {
isMatch("唐", "[\u4E00-\u9FA5]");
isMatch("晴", "[一-龥]");
} protected static void isMatch(String source, String regexStr) {
boolean result = source.matches(regexStr);
System.out.println(result);
}
}

true
true