Read json file from resources folder in Java

[goyalkritika]

I have a resources folder parallel to my core bundle in project codebase. There is a json file in it. I want to read that json file from my Java class and fetch the value for a particular key from it. How can I do so?

[Hemant_arora]

1. Add Jackson Dependency: First, you need to add the Jackson dependency to your project. If you're using Maven, add the following dependency to your pom.xml file:

2. <dependency> <groupId>com.fasterxml.jackson.core</groupId> <artifactId>jackson-databind</artifactId> <version>2.13.0</version> <!-- Use the latest version available --> </dependency>

import com.fasterxml.jackson.databind.JsonNode; import com.fasterxml.jackson.databind.ObjectMapper; import java.io.File; import java.io.IOException; public class JsonFileReader { public static void main(String[] args) { // Define the path to your JSON file String jsonFilePath = "path/to/your/file.json"; // Create an ObjectMapper instance (part of Jackson) ObjectMapper objectMapper = new ObjectMapper(); try { // Read the JSON file and parse it into a JsonNode JsonNode rootNode = objectMapper.readTree(new File(jsonFilePath)); // Specify the key you want to fetch String keyToFetch = "your_key_here"; // Fetch the value for the specified key JsonNode valueNode = rootNode.get(keyToFetch); // Check if the key exists in the JSON if (valueNode != null) { // Get the value as a String (you can use other methods like getInt, getBoolean, etc.) String value = valueNode.asText(); System.out.println("Value for key '" + keyToFetch + "': " + value); } else { System.out.println("Key '" + keyToFetch + "' not found in the JSON."); } } catch (IOException e) { e.printStackTrace(); } } }

Replace "path/to/your/file.json" with the actual path to your JSON file, and "your_key_here" with the key you want to fetch

[goyalkritika]

How exactly should I put the path to file if below is the structure of my project and I'm trying to access lobMap.json?

[Mahedi_Sabuj · Accepted solution]

You can refer to an existing thread [1] to understand how to read a JSON file from the resource folder. 

import com.fasterxml.jackson.databind.ObjectMapper;
import com.fasterxml.jackson.databind.type.CollectionType;
import com.fasterxml.jackson.databind.type.TypeFactory;
import com.fasterxml.jackson.databind.JsonNode;
import org.osgi.framework.FrameworkUtil;

// Assuming you have the ObjectMapper instance ready.
ObjectMapper objectMapper = new ObjectMapper();

// Load the JSON file directly into a JsonNode
JsonNode jsonNode = objectMapper.readTree(FrameworkUtil.getBundle(YourModel.class)
        .getBundleContext()
        .getBundle()
        .getResource("lobMap.json"));

[1]: https://experienceleaguecommunities.adobe.com/t5/adobe-experience-manager/how-to-read-a-json-file-an...

[fdambrosio]

Hello,

we are using fasterxml , but with the laster 2023.10 sdk for AEM As a Cloud Service, the build fail because of class not found for anything about com.fasterxml.jackson : 

some example: 

Caused by: java.lang.ClassNotFoundException: com.fasterxml.jackson.databind.util.internal.PrivateMaxEntriesMap$Builder

Caused by: java.lang.NoClassDefFoundError: Could not initialize class com.fasterxml.jackson.databind.ObjectMappe

Downgrading to 2023.8 or 2023.9 all build and works correctly .

Thanks,

Francesco 

[kautuk_sahni]

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