Question

我已经使用双向onetomany关联两个实体。我想使用带有投影的条件（仅从少数几列获取数据）来获得许多Person个Adress个。来自查询的结果我想放入List<Map<String, Object>>。结果列表应具有此结构（地址数据应为父地址对象中包含的List<Map<String, Object>>）：

[
   {
     name: "Andrew"
     surname: "..."
     adress : [
        {
            city : "New York"
            street : "..."
            type : "home"
        }
        {
            city : "..."
            street : "..."
            type : "work:
        }
     ]
  { 
     name: "..."
     surname : "..."
     address : [{....}]
   }
]

实体：

public class Person{
     private Long id;
     private String name;
     private String surname;
     private Integer age;
     private String phoneNr;

     @OneToMany(cascade = CascadeType.ALL, mappedBy = "person", fetch = FetchType.LAZY)
     private List<Address> addresses

    // getters and setters
}


public class Address{
     private Long id;
     private String city;
     private String street;
     @ManyToOne(fetch=FetchType.LAZY)
 @JoinColumn(name="person_id")
     private Person person;


     // getters and setters
}

我所能做到的只是加载整个实体，不符合我的需求。

Criteria criteria = currentSession().createCriteria(Person.class);
criteria.setFetchMode("addresses", FetchMode.JOIN);
criteria.setResultTransformer(Criteria.DISTINCT_ROOT_ENTITY);

任何建议都会非常有帮助。

Answer 1

我认为不可能从查询中返回List<Map<String, Object>>。获得所需结构的最简单方法是手动创建它（至少我是这么认为）：

List<Map<String, Object>> resultsList = new ArrayList<Map<String, Object>>();
List<Person> persons = criteria.list();

for (Person person: persons) {
   resultsList.put("name", person.getName());
   resultsList.put("surname", person.getSurname());
   List<Map<Strin, Object>> addressesList = new ArrayList<Map<Strin, Object>>();
   for(Address address: person.getAddresses()) {
       addressesList.put("city", address.getCity());
       addressesList.put("street", address.getStreet());
       addressesList.put("type", address.getType());   
   }
   resultsList.put("name", person.ngetName());
}

此 resultsList 将包含您需要的结构。

标准，预测，ALIAS_TO_ENTITY_MAP

1 个答案: