Pretty-print a Map in Java

print_map.java

//as json
new Gson().toJson(map)
  
//as json
ObjectMapper mapper = new ObjectMapper();
mapper.writerWithDefaultPrettyPrinter().writeValueAsString(object);

//as json
Map<String, Object> stats = ...;
System.out.println(new JSONObject(stats).toString(2));
  
//fast
Arrays.toString(map.entrySet().toArray())
  
// Have a look at the Guava library:
Joiner.MapJoiner mapJoiner = Joiner.on(",").withKeyValueSeparator("=");
System.out.println(mapJoiner.join(map));

//Apache libraries to the rescue!
MapUtils.debugPrint(System.out, "myMap", map);

//using java8
map.forEach((key, value) -> System.out.println(key + ":" + value));

//with java 8 streams more verbose
Map<Object, Object> map = new HashMap<>();
String content = map.entrySet()
                    .stream()
                    .map(e -> e.getKey() + "=\"" + e.getValue() + "\"")
                    .collect(Collectors.joining(", "));
System.out.println(content);

//verbose
public class PrettyPrintingMap<K, V> {
    private Map<K, V> map;

    public PrettyPrintingMap(Map<K, V> map) {
        this.map = map;
    }

    public String toString() {
        StringBuilder sb = new StringBuilder();
        Iterator<Entry<K, V>> iter = map.entrySet().iterator();
        while (iter.hasNext()) {
            Entry<K, V> 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();

    }
}