正则表达式在Java中应用的三种典型场合:验证,查找和替换

时间:2023-03-10 04:57:01
正则表达式在Java中应用的三种典型场合:验证,查找和替换

正则式在编程中常用,总结在此以备考:

package regularexp;

import java.util.regex.Matcher;
import java.util.regex.Pattern; public class RegUsages {
// 验证例子
private static boolean verify(String code) {
final String patternStr = "\\d+";
return Pattern.matches(patternStr, code);
}
// 查找例子
private static void search() {
Pattern pattern = Pattern.compile("m(o+)n", Pattern.CASE_INSENSITIVE); Matcher matcher=pattern.matcher("Sun Earth moon mooon Mon mooooon Mooon Mars");
while(matcher.find()) {
System.out.println(String.format("%s (%d~%d)", matcher.group(0),matcher.start(),matcher.end()));
}
}
// 更替例子1
private static void replace1() {
String str = "10元 1000人民币 10000元 100000RMB";
str = str.replaceAll("(\\d+)(元|人民币|RMB)", "$1圆");
System.out.println(str);
}
// 更替例子2
private static void replace2() {
Pattern p = Pattern.compile("m(o+)n", Pattern.CASE_INSENSITIVE); Matcher m = p.matcher("Sun Earth moon mooon Mon mooooon Mooon Mars");
StringBuffer sb = new StringBuffer(); boolean result = m.find(); while (result) {
m.appendReplacement(sb, "Moon");
result = m.find();
}
m.appendTail(sb); System.out.println("Result=" + sb.toString());
} public static void main(String[] args) {
System.out.println(String.format("601857 %s a stock code.",verify("601857")?"is":"isn't"));
search();
replace1();
replace2();
}
}

输出:

601857 is a stock code.
moon (10~14)
mooon (15~20)
Mon (21~24)
mooooon (25~32)
Mooon (33~38)
10圆 1000圆 10000圆 100000圆
Result=Sun Earth Moon Moon Moon Moon Moon Mars

--2020-03-06--