Question

我正在尝试实现一种方法，在该方法中，我创建键的Hashmap（字符串和值作为对象）。使用此哈希图，我需要搜索和排序Mongo中存在的数据集合。

下面是mongo db文件的id类：

public class Oid{
            String $oid;
            public String get$oid() {
                return $oid;
            }

            public void set$oid(String $oid) {
                this.$oid = $oid;
            }
        }

下面是pojo Java文件：

public class AppUser {
  private String password;
  private String email;
  private Date created_at;
  private Date update_at;
  Oid _id;

  public AppUser() {
   super();
   // TODO Auto-generated constructor stub
  }
  public AppUser(String password, String email, Date created_at, Date update_at) {
   super();
   this.password = password;
   this.email = email;
   this.created_at = created_at;
   this.update_at = update_at;
  }
  public String getPassword() {
   return password;
  }
  public void setPassword(String password) {
   this.password = password;
  }
  public String getEmail() {
   return email;
  }
  public void setEmail(String email) {
   this.email = email;
  }
  public Date getCreated_at() {
   return created_at;
  }
  public void setCreated_at(Date created_at) {
   this.created_at = created_at;
  }
  public Date getUpdate_at() {
   return update_at;
  }
  public void setUpdate_at(Date update_at) {
   this.update_at = update_at;
  }
  public Oid get_id() {
   return _id;
  }
  public void set_id(Oid _id) {
   this._id = _id;
  }
 }

我正在使用gson转换此pojo，同时将其转换回java对象。

public class AppUserDao {
 public List < AppUser > findMulitple(HashMap < String, Object > map) {
  List < AppUser > appUsers = new ArrayList < > ();

  MongoDatabase db = getDB();
  BasicDBObject query = new BasicDBObject(map.keySet().iterator().next(), map.get(map.keySet().toArray()[0]));
  int i = 0;
  for (String key: map.keySet()) {
   if (i != 0) {
    query.append(key, map.get(key));
   }
   i++;
  }

  FindIterable < Document > filter = db.getCollection("sampleCollection").find(query);
  MongoCursor < Document > cursor = filter.iterator();
  try {
   String obj = cursor.next().toJson();
   System.out.println(obj);
   AppUser appUser = gson.fromJson(obj, AppUser.class);
   appUsers.add(appUser);
  } catch (JsonSyntaxException jse) {
   jse.printStackTrace();
  } catch (Exception e) {
   e.printStackTrace();
  } finally {
   cursor.close();
  }
  return appUsers;
 }

}

我在其中发送键的哈希图及其属性以进行过滤。

下面是用于测试的单元测试类：

public class TestAppUser {
  public static void main(String args[]) {


   HashMap < String, Object > map = new HashMap < > ();
   map.put("email", "berry.sanford@yahoo.com");
   map.put("password", "Quo Lux");


   AppUserDao appUserDao = new AppUserDao();
   List < AppUser > appUsers = appUserDao.findMulitple(map);
   for (AppUser appUser: appUsers) {
    System.out.println(appUser.get_id().get$oid());
   }
  }
 }

在这个测试课程中，我希望获得两个记录的列表。第一个记录的电子邮件值为“ berry.sanford@yahoo.com”，第二个记录的密码为Quo Lux

Answer 1

我将构建查询过滤器并按如下所示排序顺序。

List<Bson> filters = map.entrySet().stream().map(entry->Filters.eq(entry.getKey(), entry.getValue())).collect(Collectors.toList());
List<Bson> sorts = map.keySet().stream().map(Sorts::ascending).collect(Collectors.toList());
FindIterable<Document> filter = db.getCollection("sampleCollection").find(Filters.and(filters)).sort(Sorts.orderBy(sorts));
MongoCursor<Document> cursor = filter.iterator();

MongoDb-如何使用Java对集合中的多个字段进行排序和搜索

1 个答案: