无法全部替换为美元符号

Question

can anyone advise why i encountered index out of bouns exception when running this method to replace the value by $ sign?

Eg i pass in a message $$vmdomodm$$

message = message.replaceAll("$", "$");

I tried to look at this forum thread but couldnt understand the content

http://www.coderanch.com/t/383666/java/java/String-replaceAll

Answer 1

It is special character you need to use escape character

Try with this \\\\$

and it doesn't make sense in your code you are trying to replacing the content with same

String message = "$$hello world $$";
message = message.replaceAll("\\$", "_");
System.out.println(message);

output

__hello world __

---

Update

   String message = "$hello world $$";
   message = message.replaceAll("$", "\\$");
   System.out.println(message);

output

 $hello world $$

Answer 2

由于您并没有真正使用任何正则表达式，因此您应该使用String#replace方法代替 replaceAll，如下所示：

message = message.replace("$", "$");

Answer 3

After tinkering around with replaceAll() and never getting what I wanted I figured it would be easier to write a function to escape the dollar signs.

public static String escapeDollarSign(String value) {
    Pattern p = Pattern.compile("\\$");
    int off = 0;
    while (true) {
        Matcher m = p.matcher(value.substring(off));
        if (!m.find()) break;
        int moff = m.start();
        String left = value.substring(0, off+moff);
        String right = value.substring(off+moff+1, value.length());
        value = left+"\\$"+right;
        off += moff+1+1;
    }

    return value;
}

eg
$re$gex $can $ b$ea$ pain$
becomes
\\$re\\$gex \\$can \\$ b\\$ea\\$ pain\\$

Answer 4

if(!str.isempty() && str.contains("$")){
   str = str.replaceAll("\\$", Matcher.quoteReplacement("\\$"))
}