What's the best way to convert pojo to JSON in Spring
If you don't want to use Spring MVC to convert object to JSON string, you could do it like this:
private JsonGenerator jsonGenerator = null;
private ObjectMapper objectMapper = null;
public void init(){
objectMapper = new ObjectMapper();
try{
jsonGenerator = objectMapper.getJsonFactory().createJsonGenerator(System.out, JsonEncoding.UTF8);
jsonGenerator.writeObject(bean);
objectMapper.writeValue(System.out, bean);
}catch (IOException e) {
e.printStackTrace();
}
jsonGenerator.flush();
jsonGenerator.close();
}
You must declare the bean like this
public class AccountBean {
private int id;
private String name;
private String email;
private String address;
private Birthday birthday;
//getters, setters
@Override
public String toString() {
return this.name + "#" + this.id + "#" + this.address + "#" + this.birthday + "#" + this.email;
}
}
Spring boot uses Jackson libraries to convert Java POJO Object to/from Json. These converters are created and used automatically for Rest services to convert POJO object returned by Rest method to Json (e.g. Rest service methods annotated with @ResponseBody). If Rest services are used then Spring creates POJO/Json converters automatically. If you want to make POJO/Json conversion in some different case you need com.fasterxml.jackson.databind.ObjectMapper.
Avoid creating ObjectMapper instance by operator new, reuse the ObjectMapper already available in Spring application context using dependency injection annotation @Autowired. Spring will automatically inject value to your objectMapper variable.
public class clA {
@Autowired
private ObjectMapper objectMapper;
public Optional<String> objToJson(MyObj obj) {
try {
String objJackson = objectMapper.writerWithDefaultPrettyPrinter().writeValueAsString(obj));
} catch (JsonProcessingException e) {
log.debug("failed conversion: Pfra object to Json", e);
}
});
}