这是一个SSCCE，显示研究，不是骗子而且是主题！！！
Spring Boot REST 服务和 MySQL 在这里。我有以下Profile实体：
@Entity
@Table(name = "profiles")
public class Profile extends BaseEntity {
@Id
@GeneratedValue(strategy = GenerationType.IDENTITY)
private Long id;
@Column(name = "profile_given_name")
private String givenName;
@Column(name = "profile_surname")
private String surname;
@Column(name = "profile_is_male")
private Integer isMale;
@Column(name = "profile_height_meters", columnDefinition = "DOUBLE")
private BigDecimal heightMeters;
@Column(name = "profile_weight_kilos", columnDefinition = "DOUBLE")
private BigDecimal weightKilos;
@Column(name = "profile_dob")
private Date dob;
// Getters, setters & ctor down here
}
我也有一个ProfileController并且我想公开一个 GET 端点，它提供了一种非常灵活/稳健的方式来Profiles根据大量条件进行搜索：
# Search for women between 1.2 and 1.8 meters tall.
GET /v1/profiles?isMale=0&heightMeters={"gt": 1.2, "lt": 1.8}
# Search for men born after Jan 1, 1990 who weigh less than 100 kg.
GET /v1/profiles?isMale=1&dob={"gt" : "1990-01-01 00:00:00"}&weightKilos={"lt": 100.0}
等等
所以这是我的控制器：
@RestController
@RequestMapping("/v1/profiles")
public class ProfileResource {
@Autowired
ProfileRepository profileRepository;
@GetMapping
public ResponseEntity<Set<Profile>> searchProfiles(@RequestParam(value = "isMale", required = false) String isMaleVal,
@RequestParam(value = "heightMeters", required = false) String heightMetersVal,
@RequestParam(value = "weightKilos", required = false) String weightKilosVal,
@RequestParam(value = "dob", required = false) String dobVal) {
Integer isMaleVal;
BooleanCriteria isMaleCriteria;
if(isMaleVal != null) {
// Parse the value which could either be "0" for female, "1" for male or something like
// ?isMale={0,1} to indicate
// BooleanCriteria would store which values male, female or both) to include in the search
}
BigDecimal heighMeters;
BigDecimalCriteria heightCriteria;
if(heightMetersVal != null) {
// Parse the value which like in the examples could be something like:
// ?heightMeters={"gt" : "1.0"}
// BigDecimalCriteria stores range information
}
BigDecimal heighMeters;
BigDecimalCriteria weightCriteria;
if(weightKilosVal != null) {
// Parse the value which like in the examples could be something like:
// ?weightKilos={"eq" : "100.5"}
// BigDecimalCriteria stores range information
}
// Ditto for DOB and DateCriteria
// TODO: How to pack all of these "criteria" POJOs into a
// CrudRepository/JPQL query against the "profiles" table?
Set<Profile> profiles = profileRepository.searchProfiles(
isMaleCriteria, heightCriteria, weightCriteria, dobCriteria);
}
}
比如说，我的想法BigDecimalCriteria是：
// Basically it just stores the (validated) search criteria that comes in over the wire
// on the controller method
public class BigDecimalCriteria {
private BigDecimal lowerBound;
private Boolean lowerBoundInclusive;
private BigDecimal upperBound;
private Boolean upperBoundInclusive;
// Getters, setters, ctors, etc.
}
由于所有这些搜索条件都是可选的（因此可以是可选的null），所以我被困在如何在以下位置编写 JPQL 查询ProfileRepository：
public interface ProfileRepository extends CrudRepository<Profile,Long> {
@Query("???")
public Set<Profile> searchProfiles();
}
如何以启用所有搜索条件的方式实现@Query(...)for ProfileRepository#searchProfiles（给定所有允许的范围和要搜索的条件值），并允许任何条件为空/可选？
当然，如果有任何漂亮的小库或者 Spring Boot/JPA 已经有解决方案，我全都听好了！