1. Introduction
Jackson's @JsonRawValue annotation allows you to serialize a property as raw JSON, meaning the value will be included in the output as is without standard serialization. This is particularly useful when you have a string property containing valid JSON content that you want to include as a part of the serialized JSON output without it being escaped.
2. Example Steps
1. Create a Widget class with a field that contains raw JSON content.
2. Annotate the raw JSON field with @JsonRawValue.
3. Serialize an instance of the Widget class.
4. Observe the serialized JSON string's output.
3. Java Jackson @JsonRawValue Example
import com.fasterxml.jackson.annotation.JsonRawValue;
import com.fasterxml.jackson.databind.ObjectMapper;
public class JacksonJsonRawValueExample {
public static void main(String[] args) throws Exception {
// Initialize ObjectMapper
ObjectMapper mapper = new ObjectMapper();
// Create an instance of Widget with raw JSON configuration
Widget widget = new Widget("Button", "{\"color\":\"blue\",\"size\":\"large\"}");
// Serialize the Widget instance to JSON string
String serializedWidget = mapper.writeValueAsString(widget);
// Print the serialized string
System.out.println(serializedWidget);
}
static class Widget {
private String name;
@JsonRawValue
private String configuration;
public Widget(String name, String configuration) {
this.name = name;
this.configuration = configuration;
}
// Standard getters and setters
}
}
Output:
{"name":"Button","configuration":{"color":"blue","size":"large"}}
4. Step By Step Explanation
In the Widget class, the configuration field contains a raw JSON string. By annotating it with @JsonRawValue, we instruct Jackson to include its content as-is in the serialized JSON output. As a result, in the serialized JSON string, the content of the configuration field is incorporated as a JSON object, not as an escaped string.
This demonstrates the power of the @JsonRawValue annotation to include raw JSON content directly in the serialization output.