我正在使用 Spring Boot 和 Hibernate 开发一个休息项目，目前正在尝试弄清楚如何处理我的 json 序列化。
上面 ERD 中显示的模式由 Hibernate 映射并且工作正常。
当我向控制器发出获取请求时，就会出现问题。我的理解是 Spring 现在尝试使用 Jackson 序列化对象链。因为父对象和子对象都有一个属性，所以我们发现自己遇到了一个无限递归循环。
现在我研究了@JsonIgnore、@JsonView、@JsonManagedReference 和@JsonBackReference，但这些似乎只适用于一对多关系。
我正在寻找的是一种情况，例如，当我向 GET 请求时/users/{id}，我得到了用户对象，包括它的所有关系属性（我们称之为完整对象），但关系属性本身并没有显示它们的关系-属性（最小化对象）。这适用于上面提到的注释，但是我如何使这个工作也以另一种方式工作呢？
期望的响应：/users/{id}
{ // full user object
id: 1,
username: 'foo',
// password can be JsonIgnored because of obvious reasons
role: { // minimized role object
id: 1,
name: 'bar'
// NO USERS LIST
}
area: { //minimized area object
id: 2,
name: 'some val'
// NO USERS LIST
// NO TABLES LIST
}
}
期望的响应/userrole/{id}
{ // full role object
id: 1,
name: 'waiter'
users: [
{ // minmized user object
id: 1,
username: 'foo'
// password can be JsonIgnored because of obvious reasons
// NO ROLE OBJECT
// NO AREA OBJECT
},
{ // minmized user object
id: 1,
username: 'foo'
// password can be JsonIgnored because of obvious reasons
// NO ROLE OBJECT
// NO AREA OBJECT
}
]
}
一般来说：当直接向实体发出请求时，我想要一个完整的对象，而当间接请求时，我想要一个最小化的对象。
有任何想法吗？我希望我的解释足够清楚。
更新
评论部分中要求的区域、用户和用户角色 POJO。
用户
@Entity
@Table(name = "users", schema = "public", catalog = "PocketOrder")
public class User {
private int id;
private String username;
private String psswrd;
private List<Area> areas;
private UserRole Role;
@Id
@Column(name = "id", nullable = false)
public int getId() {
return id;
}
public void setId(int id) {
this.id = id;
}
@Basic
@Column(name = "username", nullable = false, length = 20)
public String getUsername() {
return username;
}
public void setUsername(String username) {
this.username = username;
}
@Basic
@JsonIgnore
@Column(name = "psswrd", nullable = true, length = 40)
public String getPsswrd() {
return psswrd;
}
public void setPsswrd(String psswrd) {
this.psswrd = psswrd;
}
@Override
public boolean equals(Object o) {
if (this == o) return true;
if (o == null || getClass() != o.getClass()) return false;
User user = (User) o;
if (id != user.id) return false;
if (username != null ? !username.equals(user.username) : user.username != null) return false;
if (psswrd != null ? !psswrd.equals(user.psswrd) : user.psswrd != null) return false;
return true;
}
@Override
public int hashCode() {
int result = id;
result = 31 * result + (username != null ? username.hashCode() : 0);
result = 31 * result + (psswrd != null ? psswrd.hashCode() : 0);
return result;
}
@ManyToMany(mappedBy = "users")
public List<Area> getAreas() {
return areas;
}
public void setAreas(List<Area> areas) {
this.areas = areas;
}
@ManyToOne
@JoinColumn(name = "role_fk", referencedColumnName = "id", nullable = false)
public UserRole getRole() {
return Role;
}
public void setRole(UserRole role) {
Role = role;
}
}
用户角色
@Entity
@javax.persistence.Table(name = "userroles", schema = "public", catalog = "PocketOrder")
public class UserRole {
private int id;
private String name;
private List<User> users;
@Id
@Column(name = "id", nullable = false)
public int getId() {
return id;
}
public void setId(int id) {
this.id = id;
}
@Basic
@Column(name = "name", nullable = false, length = 20)
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
@Override
public boolean equals(Object o) {
if (this == o) return true;
if (o == null || getClass() != o.getClass()) return false;
UserRole userRole = (UserRole) o;
if (id != userRole.id) return false;
if (name != null ? !name.equals(userRole.name) : userRole.name != null) return false;
return true;
}
@Override
public int hashCode() {
int result = id;
result = 31 * result + (name != null ? name.hashCode() : 0);
return result;
}
@OneToMany(mappedBy = "role")
public List<User> getUsers() {
return users;
}
public void setUsers(List<User> users) {
users = users;
}
}
区域
@Entity
@javax.persistence.Table(name = "areas", schema = "public", catalog = "PocketOrder")
public class Area {
private int id;
private String name;
private List<User> users;
private List<Table> tables;
@Id
@Column(name = "id", nullable = false)
public int getId() {
return id;
}
public void setId(int id) {
this.id = id;
}
@Basic
@Column(name = "name", nullable = false, length = 20)
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
@Override
public boolean equals(Object o) {
if (this == o) return true;
if (o == null || getClass() != o.getClass()) return false;
Area area = (Area) o;
if (id != area.id) return false;
if (name != null ? !name.equals(area.name) : area.name != null) return false;
return true;
}
@Override
public int hashCode() {
int result = id;
result = 31 * result + (name != null ? name.hashCode() : 0);
return result;
}
@ManyToMany
@JoinTable(name = "areas_users", catalog = "PocketOrder", schema = "public", joinColumns = @JoinColumn(name = "area_fk", referencedColumnName = "id", nullable = false), inverseJoinColumns = @JoinColumn(name = "user_fk", referencedColumnName = "id", nullable = false))
public List<User> getUsers() {
return users;
}
public void setUsers(List<User> users) {
this.users = users;
}
@OneToMany(mappedBy = "area")
public List<Table> getTables() {
return tables;
}
public void setTables(List<Table> tables) {
this.tables = tables;
}
}