java正则表达式

正则表达式

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一，java.util.regex包中提供了两个类来表示对正则表达式的支持

1.Matcher，通过解释Pattern对character sequence 执行匹配操作的引擎

public final class Matcher implements MatchResult

2.Pattern，正则表达式的编译表示形式

public final class Pattern implements java.io.Serializable

代码：

package yuki.regular;
import java.util.regex.Matcher;
import java.util.regex.Pattern;
public class FirstTest {
    public static void main(String[] args) {
        /**
         * Pattern，正则表达式的编译表示形式
         * public final class Pattern implements java.io.Serializable
         */
        String str = "hi! i am a tony; glad to see you!";
        String regex = "\\p{Punct}";
        Pattern pattern = Pattern.compile(regex);
        String[] strArr =  pattern.split(str);
        for(int i = 0; i < strArr.length; ++i)
            System.out.println("strArr[" + i + "] = " + strArr[i]);
        /**
         * Matcher，通过解释Pattern对character sequence执行匹配操作
         * public final class Matcher implements MatchResult
         */
        Matcher matcher = pattern.matcher(str);
        System.out.println(matcher.matches() ? "匹配" : "不匹配");
        System.out.println(
                Pattern.compile("\\p{Punct}+").matcher(".,.;").matches() 
                ? "匹配" : "不匹配");
        String s2 = "yuki@gmail.com";
        Pattern p2 = Pattern.compile("\\w+@\\w+.[a-zA-Z]+");
        Matcher m2 = p2.matcher(s2);
        System.out.println("m2.matches() = " + m2.matches());
    }
}

运行结果：

strArr[0] = hi
strArr[1] =  i am a tony
strArr[2] =  glad to see you
不匹配
匹配
m2.matches() = true

二，String类对正则的支持

代码：

package yuki.regular;
import java.util.regex.Matcher;
import java.util.regex.Pattern;
public class SecondTest {
    public static void main(String[] args) {
        /**
         * 匹配替换
         */
        String date = "2015/2/27";
        Pattern p = Pattern.compile("/");
        Matcher m = p.matcher(date);
        String s = m.replaceAll("-");
        System.out.println("m.matches() = " + m.matches());
        System.out.println("s = " + s); 
        System.out.println("m.replaceFirst(\"-\") = " + m.replaceFirst("-"));
        //匹配电话号码
        String phone = "0755-28792686";
        String regex = "\\d{3,4}-\\d{7,8}";
        boolean isPhone = phone.matches(regex);
        System.out.println("isPhone = " + isPhone);
    }
}

运行结果：

m.matches() = false
s = 2015-2-27
m.replaceFirst("-") = 2015-2/27
isPhone = true

三，常用示例

代码：

package yuki.regular;
public class ThirdTest {
    public static void main(String[] args) {
        /**
         * 至少含有字符串数组中的一个
         */
        String s = "123,456,789,012,345";
        String s2 = "123,456,789,013,345";
        String regex = ".*(234|678|012).*";
        boolean isMatch = s.matches(regex);
        boolean isMatch2 = s2.matches(regex);
        System.out.println("isMatch = " + isMatch);
        System.out.println("isMatch2 = " + isMatch2);
        //匹配金额
        String price = "499.00";
        System.out.println("price.matches(\"\\d+.\\d+\")" + price.matches("\\d+.\\d+"));
    }
}

运行结果：

isMatch = true
isMatch2 = false
price.matches("\d+.\d+")true

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更多参考：
API：java.util.regex
兄弟连_马剑威JAVA基础正则表达式

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