关于一个正则表达式在 Java 里面匹配不到的奇怪问题

This topic created in 2578 days ago, the information mentioned may be changed or developed.

我需要匹配一行字符串里面所有的 ${} 占位符，使用的正则表达式为

\$\{(.*?)\}

测试字符串为：

hello, ${name}. Your level is ${level}

我用 OSChina 的在线正则表达式测试工具 http://tool.oschina.net/regex/ 进行测试，可以正确匹配到两个占位符。

但是我在 Java 里面就不能匹配到。

Pattern pattern = Pattern.compile("\\$\\{(.*?)\\}"); String test = "hello, ${name}. Your level is ${level}"; Matcher matcher = pattern.matcher(test); System.out.println(matcher.matches()); // 输出 false

求教这是怎么回事~~懵逼了一早上

4 replies 2019-04-30 14:10:01 +08:00

c4f36e5766583218

Apr 30, 2019

http://tool.oschina.net/uploads/apidocs/jdk-zh/java/util/regex/Matcher.html#matches()
当且仅当整个区域序列匹配此匹配器的模式时才返回 true。

iffi

Apr 30, 2019

这样子来
```public static void main(String[] args) {
Pattern pattern = Pattern.compile("\\$\\{(.*?)\\}");
String test = "hello, ${name}. Your level is ${level}";
Matcher matcher = pattern.matcher(test);
while (matcher.find())
System.out.println(matcher.group());
}
}
```

Defined

Apr 30, 2019

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

final String regex = "\\$\\{(.*?)\\}";
final String string = "hello, ${name}. Your level is ${level}\n";

final Pattern pattern = Pattern.compile(regex, Pattern.MULTILINE);
final Matcher matcher = pattern.matcher(string);

while (matcher.find()) {
System.out.println("Full match: " + matcher.group(0));
for (int i = 1; i <= matcher.groupCount(); i++) {
System.out.println("Group " + i + ": " + matcher.group(i));
}
}

mooncakejs

Apr 30, 2019

java 坑爹处就是 matches 从头匹配到尾