Java Regex Replace Non-Greedy not work

Asked Jun 13 '18 at 07:05

Active Jun 13 '18 at 07:26

Viewed 245 times

I want to delete all "key":null patterns from json string.

String jsonStr = "{\"a\":null,\"b\":1,\"c\":null,\"d\":5}";
System.out.println(jsonStr.replaceAll("\".*?\":null,", ""));

I expected

{"b":1,"d":5}

But result is

{"d":5}

Obviously, non greedy is not applied.

I tried with Pattern, Matcher. But it also results in same result.

Pattern replace = Pattern.compile("\".*?\":null,");
Matcher matcher = replace.matcher(jsonStr);
System.out.println(matcher.replaceAll(""));

edited Jun 13 '18 at 07:26

Hearen

asked Jun 13 '18 at 07:05

reapasisow

Replace `"\".*?\":null,"` with `"\"[^\"]*\":null,"` as `.` matches any char. – Wiktor Stribiżew Jun 13 '18 at 07:07
3

@WiktorStribiżew Better yet, use a JSON parser. A bit more overhead, but as the JSON grows, this is probably a safer option. – Tim Biegeleisen Jun 13 '18 at 07:08
@TimBiegeleisen You could help better if you found a good close reason. All these comments "use what you have never seen before" do not really help OPs. – Wiktor Stribiżew Jun 13 '18 at 07:11
Here is a link: https://stackoverflow.com/questions/2591098/how-to-parse-json-in-java – Tim Biegeleisen Jun 13 '18 at 07:12
Maybe [this one](https://stackoverflow.com/questions/31039207/jsonobject-remove-empty-value-pairs) is better. Closed with the post with the regex issue explanation and that JSON related one. – Wiktor Stribiżew Jun 13 '18 at 07:14

0 Answers0