解决：java.lang.IllegalArgumentException: Illegal group reference

解决：java.lang.IllegalArgumentException: Illegal group reference

 

当使用String中的replaceAll方法时，如果替换的值中包含有$符号时，在进行替换操作时会出现如下错误。

public static void main(String[] args) {
        String text = "123456";
        String replacement = "two$two";
        String resultString = text.replaceAll("2", replacement);
        System.out.println(resultString);
    }

 

错误信息:

Exception in thread "main" java.lang.IllegalArgumentException: Illegal group reference
	at java.util.regex.Matcher.appendReplacement(Matcher.java:713)
	at java.util.regex.Matcher.replaceAll(Matcher.java:813)
	at java.lang.String.replaceAll(String.java:2189)
	at org.jerval.test.Main.main(Main.java:17)

 

此时可以在进行替换操作前后分别对替换值中的$符号进行encode和decode操作，如下：

public static void main(String[] args) {
        String text = "123456";
        String replacement = "two$two";
        replacement = replacement.replaceAll("\\$", "RDS_CHAR_DOLLAR");// encode replacement;
        String resultString = text.replaceAll("2", replacement);
        resultString = resultString.replaceAll("RDS_CHAR_DOLLAR", "\\$");// decode replacement;
        System.out.println(resultString);
    }

结果：

1two$two3456