Processing JSON Data - Java - page 781

Discussion

Jackson provides many ways of working. For simple cases, you can have POJO (plain old
Java objects) converted to/from JSON more-or-less automatically, as is illustrated in
Example 19-1 .

Example 19-1. Reading and Writing POJOs with Jackson
public public class class ReadWriteJackson ReadWriteJackson {

public public static static void void main ( String [] args ) throws throws IOException {

ObjectMapper mapper = new new ObjectMapper ();

String jsonInput =
"{\"id\":0,\"firstName\":\"Robin\",\"lastName\":\"Wilson\"}" ;
Person q = mapper . readValue ( jsonInput , Person . class );
System . out . println ( "Read and parsed Person from JSON: " + q );

Person p = new new Person ( "Roger" , "Rabbit" );

System . out . print ( "Person object " + p + " as JSON = " );
mapper . writeValue ( System . out , p );

}

}

Create a Jackson ObjectMapper which can map POJOs to/from JSON.

M ap the string jsonInput into a Person object with one call to readValue() .

Co nvert the Person object p into JSON with one call to writeValue() .

Running this example produces the following output:

Read and parsed Person from JSON: Robin Wilson
Person object Roger Rabbit as JSON = {"id":0,"firstName":"Roger",
"lastName":"Rabbit","name":"Roger Rabbit"}

As another example, this code reads the “parser description” example file that opened
this chapter; notice the declaration List<String> for the array of contributors:

public public class class SoftwareParseJackson SoftwareParseJackson {

final final static static String FILE_NAME = "/json/softwareinfo.json" ;