Covert JSON hashmap to Java hashmap - json

Question

json = [{"a":"555","b":"ee"},{"a":"556","b":"rr"}]
I tried:
ObjectMapper mapper = new ObjectMapper();
TypeReference<Map<String,String>> typeRef = new TypeReference<Map<String,String>>() {};
HashMap<String, String> result = mapper.readValue(json, typeRef);
but it's not working. I suppose that's the reason is that json is a list and not a single object.
In fact, if json was {"a":"555","b":"ee"}, it works.

Answer 1

In order to solve the problem I'll use Jackson SDK.
Please download the latest version from: http://wiki.fasterxml.com/JacksonDownload
JSON TO MAP EXAMPLE:
import java.io.IOException;
import java.util.HashMap;
import java.util.Map;
import com.fasterxml.jackson.core.JsonGenerationException;
import com.fasterxml.jackson.core.type.TypeReference;
import com.fasterxml.jackson.databind.JsonMappingException;
import com.fasterxml.jackson.databind.ObjectMapper;
public class JsonMapExample {
public static void main(String[] args) {
try {
ObjectMapper mapper = new ObjectMapper();
String json = "{\"name\":\"mkyong\", \"age\":29}";
Map<String, Object> map = new HashMap<String, Object>();
// convert JSON string to Map
map = mapper.readValue(json, new TypeReference<Map<String, String>>(){});
System.out.println(map);
} catch (JsonGenerationException e) {
e.printStackTrace();
} catch (JsonMappingException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
}
}
}
Map to JSON EXAMPLE:
import java.io.IOException;
import java.util.HashMap;
import java.util.Map;
import com.fasterxml.jackson.core.JsonGenerationException;
import com.fasterxml.jackson.databind.JsonMappingException;
import com.fasterxml.jackson.databind.ObjectMapper;
public class MapJsonExample{
public static void main(String[] args) {
try {
ObjectMapper mapper = new ObjectMapper();
String json = "";
Map<String, Object> map = new HashMap<String, Object>();
map.put("name", "mkyong");
map.put("age", 29);
// convert map to JSON string
json = mapper.writeValueAsString(map);
System.out.println(json);
json = mapper.writerWithDefaultPrettyPrinter().writeValueAsString(map);
// pretty print
System.out.println(json);
} catch (JsonGenerationException e) {
e.printStackTrace();
} catch (JsonMappingException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
}
}
}
JSONArray to HashMaps:
HashMap<String, String> pairs = new HashMap<String, String>();
for (int i = 0; i < myArray.length(); i++) {
JSONObject j = myArray.optJSONObject(i);
Iterator it = j.keys();
while (it.hasNext()) {
String n = it.next();
pairs.put(n, j.getString(n));
}
}