How can I convert a String
into a HashMap
?
String value = "{first_name = naresh, last_name = kumar, gender = male}"
into
Map<Object, Object> = {
first_name = naresh,
last_name = kumar,
gender = male
}
Where the keys are first_name
, last_name
and gender
and the values are naresh
, kumar
, male
.
Note: Keys can be any thing like city = hyderabad
.
I am looking for a generic approach.
This question is related to
java
collections
hashmap
Should Use this way to convert into map :
String student[] = students.split("\\{|}");
String id_name[] = student[1].split(",");
Map<String,String> studentIdName = new HashMap<>();
for (String std: id_name) {
String str[] = std.split("=");
studentIdName.put(str[0],str[1]);
}
@Test
public void testToStringToMap() {
Map<String,String> expected = new HashMap<>();
expected.put("first_name", "naresh");
expected.put("last_name", "kumar");
expected.put("gender", "male");
String mapString = expected.toString();
Map<String, String> actual = Arrays.stream(mapString.replace("{", "").replace("}", "").split(","))
.map(arrayData-> arrayData.split("="))
.collect(Collectors.toMap(d-> ((String)d[0]).trim(), d-> (String)d[1]));
expected.entrySet().stream().forEach(e->assertTrue(actual.get(e.getKey()).equals(e.getValue())));
}
try this out :)
public static HashMap HashMapFrom(String s){
HashMap base = new HashMap(); //result
int dismiss = 0; //dismiss tracker
StringBuilder tmpVal = new StringBuilder(); //each val holder
StringBuilder tmpKey = new StringBuilder(); //each key holder
for (String next:s.split("")){ //each of vale
if(dismiss==0){ //if not writing value
if (next.equals("=")) //start writing value
dismiss=1; //update tracker
else
tmpKey.append(next); //writing key
} else {
if (next.equals("{")) //if it's value so need to dismiss
dismiss++;
else if (next.equals("}")) //value closed so need to focus
dismiss--;
else if (next.equals(",") //declaration ends
&& dismiss==1) {
//by the way you have to create something to correct the type
Object ObjVal = object.valueOf(tmpVal.toString()); //correct the type of object
base.put(tmpKey.toString(),ObjVal);//declaring
tmpKey = new StringBuilder();
tmpVal = new StringBuilder();
dismiss--;
continue; //next :)
}
tmpVal.append(next); //writing value
}
}
Object objVal = object.valueOf(tmpVal.toString()); //same as here
base.put(tmpKey.toString(), objVal); //leftovers
return base;
}
examples input : "a=0,b={a=1},c={ew={qw=2}},0=a" output : {0=a,a=0,b={a=1},c={ew={qw=2}}}
String value = "{first_name = naresh,last_name = kumar,gender = male}"
Let's start
{
and }
from the String
>>first_name = naresh,last_name = kumar,gender = maleString
from ,
>> array of 3 elementarray
with 3
elementarray
and split each element by =
Map<String,String>
put each part separated by =
. first part as Key
and second part as Value
(Since I use Gson quite liberally, I am sharing a Gson based approach)
Gson gson = new Gson();
Map<Object,Object> attributes = gson.fromJson(gson.toJson(value),Map.class);
What it does is:
gson.toJson(value)
will serialize your object into its equivalent Json representation. gson.fromJson
will convert the Json string to specified object. (in this example - Map
)There are 2 advantages with this approach:
toJson
method.Source: Stackoverflow.com