我创建了两个实体。一是用户,二是位置。它具有一对多关系,即一个用户将拥有多个位置。
我能够创建用户。现在我想在某个用户下创建一个位置。
我通过 oneToMany 关系映射了两个实体。但我无法从发布的请求中获取用户的 id,因此只有位置值会插入到数据库中,而不是 user_id。
用户:
@Entity // This tells Hibernate to make a table out of this class
@Table(name = "user")
public class User {
public User() {}
public User(String email, String name) {
this.email = email;
this.name = name;
}
@Id
@GeneratedValue(strategy=GenerationType.AUTO)
@Column(name = "id")
private Long id;
@Column(name = "name")
private String name;
private String email;
private String number;
@OneToMany(cascade={CascadeType.ALL})
@Fetch(FetchMode.JOIN)
@JoinColumn(name="id", referencedColumnName="id")
private Set<Location> locations;
public Set<Location> getLocations() {
return locations;
}
public void setLocations(Set<Location> locations) {
this.locations = locations;
}
public Long getId() {
return id;
}
public void setId(Long id) {
this.id = id;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public String getEmail() {
return email;
}
public void setEmail(String email) {
this.email = email;
}
public String getNumber() {
return number;
}
public void setNumber(String number) {
this.number = number;
}
}
地点:
@Entity
@Table(name = "location")
public class Location {
@Id
@GeneratedValue(strategy=GenerationType.AUTO)
@Column(name ="id")
private Long id;
private String location;
private double latitude;
public Location() {}
@ManyToOne(fetch = FetchType.LAZY)
@JoinColumn(name = "user_id")
private User user;
@Override
public String toString() {
return "Location [id=" + id + ", location=" + location + ", latitude=" + latitude + ", longitude=" + longitude
+ "]";
}
public double getLatitude() {
return latitude;
}
public void setLatitude(double latitude) {
this.latitude = latitude;
}
public double getLongitude() {
return longitude;
}
public void setLongitude(double longitude) {
this.longitude = longitude;
}
private double longitude;
public String getLocation() {
return location;
}
public void setLocation(String location) {
this.location = location;
}
public User getUser() {
return user;
}
public void setUser(User user) {
this.user = user;
}
public char[] getId() {
// TODO Auto-generated method stub
return null;
}
}
位置 Controller :
@Controller // This means that this class is a Controller
@RequestMapping(path="/Locations") // This means URL's start with /demo (after Application path)
public class LocationController {
@Autowired // This means to get the bean called userRepository
// Which is auto-generated by Spring, we will use it to handle the data
private LocationRepository locationRepository;
private UserRepository userRepository;
@RequestMapping("/create")
@ResponseBody
public Location create(@RequestBody Location location) {
String locId = "";
Location newLocation = new Location();
try {
locationRepository.save(location);
locId = String.valueOf(location.getId());
}
catch (Exception ex) {
// return "Error creating the user: " + ex.toString();
return location;
}
return locationRepository.save(location);
}
private User userRepository(User user) {
// TODO Auto-generated method stub
return null;
}
@GetMapping(path="/all")
public @ResponseBody Iterable<Location> getAllLocations() {
// This returns a JSON or XML with the users
return locationRepository.findAll();
}
}
位置存储库:
import org.springframework.data.repository.CrudRepository;
public interface LocationRepository extends CrudRepository<Location, Long>{
}
请求:
{
"latitude" : 15645.00,
"longitude" : 154645.00,
"location" : "dahisar"
}
回应:
{
"id": null,
"location": "dahisar",
"latitude": 15645,
"user": null,
"longitude": 154645
}
我尝试通过这种方式获取用户:
@RequestMapping("/create")
@ResponseBody
public Location create(@RequestBody Location location) {
String locId = "";
Location newLocation = new Location();
try {
User user = userRepository(location.getUser()); //Get the parent Object
newLocation = new Location(); //Create a new Many object
newLocation.setLatitude(location.getLatitude());
newLocation.setLongitude(location.getLongitude());
newLocation.setLocation(location.getLocation());
newLocation.setUser(user);
locationRepository.save(newLocation);
locId = String.valueOf(newLocation.getId());
}
catch (Exception ex) {
// return "Error creating the user: " + ex.toString();
return newLocation;
}
return locationRepository.save(newLocation);
}
我还尝试使用用户 Crud Repository 的 findById() 方法
User user = userRepository.findById(location.getUser().getId()); //Get the parent Object from database
newLocation.setLatitude(location.getLatitude());
newLocation.setLongitude(location.getLongitude());
newLocation.setLocation(location.getLocation());
newLocation.setUser(user);
newLocation = locationRepository.save(newLocation);
locId = String.valueOf(newLocation.getId());
public interface UserRepository extends CrudRepository<User, Long>{
}
然后它要求将 User 转换为用户。当我尝试转换时,方法调用仍然存在问题。
尝试像这样输入:
{
"latitude" : 15645.00,
"longitude" : 154645.00,
"location" : "dahisar",
"user" : {
"id" : "1"
}
}
我该怎么做?我是这方面的初学者,请帮忙谢谢..
请您参考如下方法:
您可能必须设置写入(保存)事务。
Session session=sessionFactory.getCurrentSession();
session.beginTransaction();
...
locationRepository.save(newLocation);
...
locationRepository.save(newLocation);
...
newLocation.setUser(user);
...
session.getTransaction().commit();