Pretty-print a Map in Java

Question

I am looking for a nice way to pretty-print a Map.

map.toString() gives me: {key1=value1, key2=value2, key3=value3}

I

Answer 1

Or put your logic into a tidy little class.

public class PrettyPrintingMap {
    private Map map;

    public PrettyPrintingMap(Map map) {
        this.map = map;
    }

    public String toString() {
        StringBuilder sb = new StringBuilder();
        Iterator> iter = map.entrySet().iterator();
        while (iter.hasNext()) {
            Entry entry = iter.next();
            sb.append(entry.getKey());
            sb.append('=').append('"');
            sb.append(entry.getValue());
            sb.append('"');
            if (iter.hasNext()) {
                sb.append(',').append(' ');
            }
        }
        return sb.toString();

    }
}

Usage:

Map myMap = new HashMap();

System.out.println(new PrettyPrintingMap(myMap));

Note: You can also put that logic into a utility method.