如何在运行时从字符串表示形式创建Java对象

Question

Eg if I have a string "{1,2,3,4,5}" I would like to get an int[] object from that string.

I have looked a bit at Janino and Beanshell, but can't seem to find the correct way to get them to do this for me.

I am looking for a generic solution, one that works for all types - not only integer arrays.

Answer 1

looks like a parse problem to me. look at the string methods :)

the code could look like:

String s = "{1,2,3,4,5}"
String justIntegers = s.substring(1, s.length()-1);
LinkedList<Integer> l = new LinkedList();
for (String string: justIntegers.split(','))
l.add(Integer.valuesOf(string));
l.toArray();

if you are using strings to send/save objects pls use xml or json...

Answer 2

Take a look at https://stackoverflow.com/a/2605050/1458047

The answer proposes a few options.

Answer 3

Better to use Regular Expression .Not necessary that your String is Array it could be any String which contains numbers.

        String s="{1,2,3,4,5}";
        Pattern p = Pattern.compile("-?\\d+");
        Matcher m = p.matcher(s);
        List<Integer> list=new ArrayList<Integer>();
        while (m.find()) {
          Integer num=new Integer(m.group());

          list.add(num);
        }

        System.out.println(list);

Output:

[1, 2, 3, 4, 5]