CODEWITHSUNDEEP
javaregexbufferedreader
AncientSwordRage
AncientSwordRage

Reputation: 7635

Escaping '{' when regex-ing in java?

I'm trying to get my code to ignore some some lines it's reading. My SSCE is thus:

public class testRegex {
    private static final String DELETE_REGEX = "\\{\"delete"; //escape the '{', escape the ' " '
    private static final String JSON_FILE_NAME = "example";
public static void main(String[] args){
    String line = null;
    try{
        BufferedReader buff = new BufferedReader (new FileReader(JSON_FILE_NAME + ".json"));
        line = buff.readLine        buff.close();
        }catch (FileNotFoundException e){e.printStackTrace();}
         catch (IOException e){e.printStackTrace();}
    String line=buff.readLine();
    System.out.println(line.contains(DELETE_REGEX));
    }
}

My file only contains the line:

{"delete":{"status":{"user_id_str":"123456789","user_id":123456789,"id_str":"987654321","id":987654321}}}

But this prints out false...is my regex wrong? I'm matching { by double escaping it with \\{ as it advises here.

The string literal "\(hello\)" is illegal and leads to a compile-time error; in order to match the string (hello) the string literal "\\(hello\\)" must be used.

And I escape the " by using \".

So how can I fix my program?

*p.s. I've tried manually inputting line = "\{\"delete" (no need to double escape as line is a string not a regex), and I get the same result.

Upvotes: 3

Views: 112

Answers (2)

Sean Patrick Floyd
Sean Patrick Floyd

Reputation: 299048

String.contains() performs an exact match, not a regex search. Do not escape the { brace.

Upvotes: 6

Denys Séguret
Denys Séguret

Reputation: 382284

The contains method doesn't take a regex as parameter so you don't have to escape the {.

Simply do

line.contains("{\"delete")

Upvotes: 1

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