正则表达式

编译正则表达式

        String re = "d+";
        Pattern compile = Pattern.compile(re);
        Matcher matcher = compile.matcher("123123123213");

提取字符串

        // 一个括号内会被分为一个group
        String re = "(\d{2}):(\d{2}):(\d{2})";
        Pattern compile = Pattern.compile(re);
        Matcher matcher = compile.matcher("24:12:64我是不匹配99:12:22");
        while (matcher.find()) {
            System.out.println("----------------");
            for (int i = 0; i <= matcher.groupCount(); i++) {
                System.out.println(i + "	:	" + matcher.group(i));
            }

        }

输出

----------------
0	:	24:12:64
1	:	24
2	:	12
3	:	64
----------------
0	:	99:12:22
1	:	99
2	:	12
3	:	22

Process finished with exit code 0

matcher 与 find的区别

matcher是一次匹配整个句子，find是尝试匹配句子中的子字符串

import java.util.regex.Matcher;
import java.util.regex.Pattern;

public class scratch_1 {

    public static void main(String[] args) {
        /**
         * 输出
         * ----------------
         * 0	:	24:12:64
         * 1	:	24:12:64
         * 2	:	24
         * 3	:	12
         * 4	:	64
         * ----------------
         * 0	:	99:12:22
         * 1	:	99:12:22
         * 2	:	99
         * 3	:	12
         * 4	:	22
         */
        String re = "((\d{2}):(\d{2}):(\d{2}))";
        Pattern compile = Pattern.compile(re);
        Matcher matcher = compile.matcher("24:12:64sjdfksjdkfj99:12:22");
        while (matcher.find()) {
            System.out.println("----------------");
            for (int i = 0; i <= matcher.groupCount(); i++) {
                System.out.println(i + "	:	" + matcher.group(i));
            }

        }

        // find
        /**
         * 输出为空，因为后面有别的单词，不完全匹配
         * 如果替换输入字符串为24:12:64，输出
         * 0	:	24:12:64
         * 1	:	24
         * 2	:	12
         * 3	:	64
         */
        String re1 = "(\d{2}):(\d{2}):(\d{2})";
        Pattern compile1 = Pattern.compile(re1);
        Matcher matcher1 = compile1.matcher("24:12:64我是不匹配99:12:22");
        if (matcher1.matches()) {
            for (int i = 0; i <= matcher1.groupCount(); i++) {
                System.out.println(i + "	:	" + matcher1.group(i));
            }
        }
    }
}