Java 8 stream: 让你的代码更简洁

# stream是Java 8 的新特性

少废话，上代码!

!

    private String rolesToString(List<User_roles> list) {//      StringBuffer sb = new StringBuffer();//      for (User_roles r : list) {//          sb.append(r.getName()).append(",");//      }//      if (sb.length() > 0)//          sb.deleteCharAt(sb.length() - 1);//      return sb.toString();        return list.stream()                  .map( it -> it.getName())                  .collect(joining(","));    }