# Convert JSON string to JsonNode using Jackson

By Atta Ur Rehman Shah (https://attacomsian.com/about). Published Nov 17, 2019, updated Oct 14, 2022. Topics: Java, JSON, Jackson.
Canonical URL: https://attacomsian.com/blog/jackson-convert-json-string-to-json-node

> A short tutorial to learn about different ways of converting JSON string to JsonNode using Jackson.

In this short tutorial, you'll learn how to parse a JSON string to a `JsonNode` object and vice versa using the [Jackson](https://attacomsian.com/blog/jackson-read-write-json) library.

## Convert JSON String to `JsonNode`

To convert a JSON string to `JsonNode`, you can use the `readTree()` method from `ObjectMapper`. This method builds a tree model for all nodes and returns the root of the tree:

```java
try {
    // JSON string
    String json = "{\"name\":\"John Doe\",\"email\":\"john.doe@example.com\"," +
            "\"roles\":[\"Member\",\"Admin\"],\"admin\":true,\"city\"" +
            ":\"New York City\",\"country\":\"United States\"}";

    // create object mapper instance
    ObjectMapper mapper = new ObjectMapper();

    // convert JSON string to `JsonNode`
    JsonNode node = mapper.readTree(json);

    // print JSON nodes
    System.out.println(node.path("name").asText());
    System.out.println(node.path("email").asText());
    System.out.println(node.path("roles").get(0).asText());

} catch (Exception ex) {
    ex.printStackTrace();
}
```

## Convert JSON File to `JsonNode`

If your JSON data is stored in an external file, you can still parse its content to `JsonNode`:

```java
try {
    // create object mapper instance
    ObjectMapper mapper = new ObjectMapper();

    // convert JSON file to `JsonNode`
    JsonNode node = mapper.readTree(Paths.get("user.json").toFile());

    // print JSON nodes
    System.out.println(node.path("name").asText());
    System.out.println(node.path("email").asText());
    System.out.println(node.path("roles").get(0).asText());

} catch (Exception ex) {
    ex.printStackTrace();
}
```

## Convert `JsonNode` to JSON String

Converting a `JsonNode` object back to a JSON string is straightforward. You can simply call the `toString()` method (or `toPrettyString()` for pretty print JSON) to get the JSON structure as a string:

```java
try {
    // create object mapper instance
    ObjectMapper mapper = new ObjectMapper();

    // convert JSON file to `JsonNode`
    JsonNode node = mapper.readTree(Paths.get("user.json").toFile());

    // `JsonNode` to JSON string
    String json = node.toPrettyString();

    // print JSON string
    System.out.println(json);
    
} catch (Exception ex) {
    ex.printStackTrace();
}
```

The above code will print the following JSON on the console:

```java
{
  "name" : "John Doe",
  "email" : "john.doe@example.com",
  "roles" : [ "Member", "Admin" ],
  "admin" : true,
  "city" : "New York City",
  "country" : "United States"
}
```

Read the guide [Working with Tree Model Nodes in Jackson](https://attacomsian.com/blog/jackson-json-node-tree-model) for more `JsonNode` examples.

For more Jackson examples, check out the [How to read and write JSON using Jackson in Java](https://attacomsian.com/blog/jackson-read-write-json) tutorial.