JSON Beautifier Library for Java

Question

I want to format a string containing JSON data using Java. Does anybody know an open source library for that.

Answer 1

With Jackson 2.6.1

String beautify(String json) throws IOException {
    ObjectMapper mapper = new ObjectMapper();
    Object obj = mapper.readValue(json, Object.class);
    return mapper.writerWithDefaultPrettyPrinter().writeValueAsString(obj);
}

pom.xml:

    <dependency>
        <groupId>com.fasterxml.jackson.core</groupId>
        <artifactId>jackson-core</artifactId>
        <version>2.6.1</version>
    </dependency>

    <dependency>
        <groupId>com.fasterxml.jackson.core</groupId>
        <artifactId>jackson-databind</artifactId>
        <version>2.6.1</version>
    </dependency>

Convert JSON String to Pretty Print JSON output using Jackson

Answer 2

Assuming you're starting out with an existing JSON string, then Jackson can do this for you:

ObjectMapper objectMapper = new ObjectMapper();
objectMapper.configure(SerializationConfig.Feature.INDENT_OUTPUT, true);

String originalJson = ...
JsonNode tree = objectMapper .readTree(originalJson);
String formattedJson = objectMapper.writeValueAsString(tree);

Answer 3

Update to previous answer by skaffman, with newer versions of Jackson (2+, I think). The second line of code is now:

objectMapper.configure(SerializationFeature.INDENT_OUTPUT, true);

Answer 4

I made a simple code can do this, you just need to create a new class call BeautifulJson and paste all of them in.

public class BeautifulJson {
    public static String beautiful(String input) {
        int tabCount = 0;

        StringBuilder inputBuilder = new StringBuilder();
        char[] inputChar = input.toCharArray();

        for (int i = 0; i < inputChar.length; i++) {
            String charI = String.valueOf(inputChar[i]);
            if (charI.equals("}") || charI.equals("]")) {
                tabCount--;
                if (!String.valueOf(inputChar[i - 1]).equals("[") && !String.valueOf(inputChar[i - 1]).equals("{"))
                    inputBuilder.append(newLine(tabCount));
            }
            inputBuilder.append(charI);

            if (charI.equals("{") || charI.equals("[")) {
                tabCount++;
                if (String.valueOf(inputChar[i + 1]).equals("]") || String.valueOf(inputChar[i + 1]).equals("}"))
                    continue;

                inputBuilder.append(newLine(tabCount));
            }

            if (charI.equals(",")) {
                inputBuilder.append(newLine(tabCount));
            }
        }

        return inputBuilder.toString();
    }

    private static String newLine(int tabCount) {
        StringBuilder builder = new StringBuilder();

        builder.append("\n");
        for (int j = 0; j < tabCount; j++)
            builder.append("  ");

        return builder.toString();
    }
}

To use this:

String beautifulJson = BeautifulJson.beautiful("JSON in string");

Example:

static String json = "{\"success\": true,\"metadata\": {\"transactionId\": 0,\"status_code\": 0},\"errors\": [{\"code\": \"string\",\"message\": \"string\"}]}";

public static void main(String[] args) {
    //Original JSON
    System.out.println(json);
    //beautiful JSON
    System.out.println(beautiful(json));
}

This is my first post on stack overflow :)