I apologize for any confusion, there is no such class in Apache Commons IO library called JsonSetter. The class JsonSetter is from Jackson library, not from Apache Commons IO.

Here is an example of using the JsonSetter annotation from the Jackson library to specify a setter method for a field when deserializing an object from JSON:

import com.fasterxml.jackson.annotation.JsonSetter;

public class MyClass {
    private String field;

    public MyClass() {}

    @JsonSetter("my_field")
    public void setField(String field) {
        this.field = field;
    }

    public String getField() {
        return field;
    }
}

In this example, the setField method is annotated with @JsonSetter("my_field") which will be used to set the value of the field when deserializing the MyClass object from JSON.

Make sure that you are using jackson as deserializer.