Java的; 字符串replaceAll给出错误

Question

I want to replace "{ from below String :

public static void main(String args[]){  
    String input="Subtitle,\"{\"key\": \"IsReprint\", \"value\":\"COPY\"}";

    input=input.replaceAll("\"{", "{"));        

    System.out.println("String ::::"+input);
}

I'm getting this error:

Exception in thread "main" java.util.regex.PatternSyntaxException: Illegal repetition near index 1
    \"{
     ^

Answer 1

You have two ways:

The first you have to escape the { with \\\\{ , because replaceAll use regex so you have to escape the " and { :

input=input.replaceAll("\"\\{", "{");   

The second is to use replace instead if you don't have this complicated regex :

input=input.replace("\"{", "{"); 

Answer 2

replaceAll takes a regex as an argument. { has a special meaning in regex, so have to escape { by doing

input=input.replaceAll("\"\\{", "{");  

or use replace , which doesn't take a regex as an argument.

input=input.replace("\"{", "{");   

Answer 3

You are not escaping the "{" character correctly when you are calling replaceAll.

You need to use "two slashes" \\\\ before any regular expression (regExp).

Here is an example:

public static void main(String args[]){
    String input="Subtitle,\"{\"key\": \"IsReprint\", \"value\":\"COPY\"}";

    System.out.println(input.replaceAll("\\{", "*"));
}

My example replaces the "{" character with a *:

"\\{", "*"

Running , you get the ouput:

Subtitle,"*"key": "IsReprint", "value":"COPY"}

---

With the input:

String input="{{ }}";

You get the output:

** }}