আমি একটি কাজের উদাহরণ অন্তর্ভুক্ত করতে রাশিডাইসাই 1 এর উত্তরটি পরিবর্তন করেছি ।
JsonMarshaller.java
import java.io.*;
import java.util.*;
public class JsonMarshaller<T> {
private static ClassLoader loader = JsonMarshaller.class.getClassLoader();
public static void main(String[] args) {
try {
JsonMarshallerUnmarshaller<Station> marshaller = new JsonMarshallerUnmarshaller<>(Station.class);
String jsonString = read(loader.getResourceAsStream("data.json"));
List<Station> stations = marshaller.unmarshal(jsonString);
stations.forEach(System.out::println);
System.out.println(marshaller.marshal(stations));
} catch (IOException e) {
e.printStackTrace();
}
}
@SuppressWarnings("resource")
public static String read(InputStream ios) {
return new Scanner(ios).useDelimiter("\\A").next(); // Read the entire file
}
}
আউটপুট
Station [id=123, title=my title, name=my name]
Station [id=456, title=my title 2, name=my name 2]
[{"id":123,"title":"my title","name":"my name"},{"id":456,"title":"my title 2","name":"my name 2"}]
JsonMarshallerUnmarshaller.java
import java.io.*;
import java.util.List;
import com.fasterxml.jackson.core.*;
import com.fasterxml.jackson.databind.*;
import com.fasterxml.jackson.databind.introspect.JacksonAnnotationIntrospector;
public class JsonMarshallerUnmarshaller<T> {
private ObjectMapper mapper;
private Class<T> targetClass;
public JsonMarshallerUnmarshaller(Class<T> targetClass) {
AnnotationIntrospector introspector = new JacksonAnnotationIntrospector();
mapper = new ObjectMapper();
mapper.getDeserializationConfig().with(introspector);
mapper.getSerializationConfig().with(introspector);
this.targetClass = targetClass;
}
public List<T> unmarshal(String jsonString) throws JsonParseException, JsonMappingException, IOException {
return parseList(jsonString, mapper, targetClass);
}
public String marshal(List<T> list) throws JsonProcessingException {
return mapper.writeValueAsString(list);
}
public static <E> List<E> parseList(String str, ObjectMapper mapper, Class<E> clazz)
throws JsonParseException, JsonMappingException, IOException {
return mapper.readValue(str, listType(mapper, clazz));
}
public static <E> List<E> parseList(InputStream is, ObjectMapper mapper, Class<E> clazz)
throws JsonParseException, JsonMappingException, IOException {
return mapper.readValue(is, listType(mapper, clazz));
}
public static <E> JavaType listType(ObjectMapper mapper, Class<E> clazz) {
return mapper.getTypeFactory().constructCollectionType(List.class, clazz);
}
}
Station.java
public class Station {
private long id;
private String title;
private String name;
public long getId() {
return id;
}
public void setId(long id) {
this.id = id;
}
public String getTitle() {
return title;
}
public void setTitle(String title) {
this.title = title;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
@Override
public String toString() {
return String.format("Station [id=%s, title=%s, name=%s]", id, title, name);
}
}
data.json
[{
"id": 123,
"title": "my title",
"name": "my name"
}, {
"id": 456,
"title": "my title 2",
"name": "my name 2"
}]