2021-10-12

public class demo01 {
public static Map groupByFirstChar(List data){
Map result = new HashMap<>();
for(Employee e : data){
// String c = e.Cid;//按车间号分组
// String c = e.gz;//按工种分组
String c = e.age;//按工龄分组
List l = result.get©;
if(l == null){
l = new ArrayList<>();
result.put(c, l);
}
l.add(e);
}
return result;
}