I have string which I split to hash map

String myStrFromUser = "app0=aaa,aaa,app1=ccc,ddd,app3=ddd,app4=iii,ddd,qqq,www,iii";
private static HashMap<String, List<String>> myMap = = new HashMap<>();
Arrays.stream(myStrFromUser.split("(,(?=[A-Za-z0-9]*=[^A-Za-z0-9]*))"))
                            .map(String::trim)
                            .map(s -> s.split("="))
                            .collect(Collectors.toMap(str -> s[0], str -> str[1].split(",")))
                            .forEach((key, value) -> myMap.put(key,  Arrays.asList(value)) );

The problem is that i like to prevent inserting duplicate values into new ArrayList<>(Arrays.asList(value))

for example :

app0=aaa,aaa 

contains duplicates so I like it to be only 1 "aaa" in the ArrayList<>(Arrays.asList(value))

CodePudding user response：

I think this is what you are looking for.

• continue to the toMap part as you did
• but for the value, simply create a new stream, splitting on the comma and converting to a list using distinct to get rid of duplicates.
• I would suggest a list over set since sets can't be indexed as they are unordered. If that doesn't matter, convert to a set and remove the distinct call. And change the Map target to Set<String>

String myStrFromUser =
        "app0=aaa,aaa,app1=ccc,ddd,app3=ddd,app4=iii,ddd,qqq,www,iii";
Map<String, List<String>> myMap = Arrays.stream(myStrFromUser
        .split("(,(?=[A-Za-z0-9]*=[^A-Za-z0-9]*))"))
        .map(String::trim).map(s -> s.split("="))
        .collect(Collectors.toMap(str -> str[0], str -> Arrays
                .stream(str[1].split(",")).distinct().collect(Collectors.toList())));


myMap.entrySet().forEach(System.out::println);

Prints

app0=[aaa]
app1=[ccc, ddd]
app4=[iii, ddd, qqq, www]
app3=[ddd]