java 替换子字符串 (replaceAll) 解决方法
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Replace substring (replaceAll) workaround
提问by user_unknown
I'm trying to replace a substring that contains the char "$". I'd be glad to hear why it didnt works that way, and how it would work.
我正在尝试替换包含字符“$”的子字符串。我很高兴听到为什么它不能那样工作，以及它是如何工作的。
Thanks, user_unknown
谢谢，user_unknown
public class replaceall {
public static void main(String args[]) {
String s1= "$foo - bar - bla";
System.out.println("Original string:\n"+s1);
String s2 = s1.replaceAll("bar", "this works");
System.out.println("new String:\n"+s2);
String s3 = s2.replaceAll("$foo", "damn");
System.out.println("new String:\n"+s3);
}
}
回答by kennytm
Java's .replaceAllimplicitly uses Regex to replace. That means, $foois interpreted as a regex pattern, and $is special in regex (meaning "end of string").
Java 的.replaceAll隐式使用 Regex 来替换。这意味着，$foo被解释为正则表达式模式，并且$在正则表达式中是特殊的（意思是“字符串结尾”）。
You need to escape the $as
你需要逃避$as
String s3 = s2.replaceAll("\$foo", "damn");
if the target a variable, use Pattern.quoteto escape all special characters on Java ≥1.5, and if the replacement is also a variable, use Matcher.quoteReplacement.
如果目标是变量，则使用Pattern.quote转义 Java ≥1.5 上的所有特殊字符，如果替换也是变量，则使用Matcher.quoteReplacement.
String s3 = s2.replaceAll(Pattern.quote("$foo"), Matcher.quoteReplacement("damn"));
On Java ≥1.5, you could use .replaceinstead.
关于Java≥1.5，你可以使用.replace代替。
String s3 = s2.replace("$foo", "damn");
Result: http://www.ideone.com/Jm2c4
回答by Sean Patrick Floyd
If you don't need Regex functionality, don't use the regex version.
如果您不需要正则表达式功能，请不要使用正则表达式版本。
Use String.replace(str, str)instead:
使用String.replace(str, str)来代替：
String s = "$$$";
String rep = s.replace("$", "");
System.out.println(rep);
// Output:
Reference:
参考：
回答by blue112
IIRC, replaceAll take a regex : Try to escape the $, this way :
IIRC，replaceAll 使用正则表达式：尝试转义 $，这样：
String s3 = s2.replaceAll("\$foo", "damn");
回答by Zip184
public static String safeReplaceAll(String orig, String target, String replacement) {
replacement = replacement.replace("$", "\$");
return orig.replaceAll(target, replacement);
}
