In this source code example, we show how to filter a map by its keys in Java 8 with an exmaple.
Java 8 Stream filter map by keys
The example filters domain names starting with s letter.:
import java.util.HashMap;
import java.util.Map;
public class JavaStreamFilterMapByKeys {
public static void main(String[] args) {
Map hmap = new HashMap<>();
hmap.put("de", "Germany");
hmap.put("in", "India");
hmap.put("sk", "Slovakia");
hmap.put("si", "Slovenia");
hmap.put("so", "Somalia");
hmap.put("us", "United States");
hmap.put("ru", "Russia");
hmap.entrySet().stream().filter(map -> map.getKey().startsWith("s"))
.forEach(m -> System.out.println(m));
}
}
Output:
si=Slovenia sk=Slovakia so=Somalia