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目录SpringBoot + JPA @ManyToMany 要点对应的Entity的建立Junit的测试JPA中ManyToMany关系问题解决办法springBoot + JPA
这里主要时记录下此种方法的注意事项。
环境 :Mysql 引擎为innoDB ,否则没有事务的说法的。
此处注意不可使用lombok @Data 注解。使用@Setter 、@Getter注解。主要原因时要自己覆写hash() equals(),toString() 方法。这样添加和删除的时候不会出现异常。否则出现循环的引用,不能删除或stackOver;
User
@Setter
@Getter
@Entity
public class User {
@Id
@GenericGenerator(name="jpauuid",strategy = "org.hibernate.id.UUIDGenerator")
@GeneratedValue(generator = "jpauuid")
@Column(length = 32,nullable = false)
private String id;
@Column(length = 30)
private String username;
@ManyToMany(cascade = CascadeType.REFRESH,mappedBy = "users")
private Set<Role> roles;
@Override
public boolean equals(Object o) {
if (this == o) return true;
if (o == null || getClass() != o.getClass()) return false;
User user = (User) o;
return id.equals(user.id) &&
username.equals(user.username) &&
roles.equals(user.roles);
}
@Override
public int hashCode() {
return Objects.hash(id, username, roles);
}
@Override
public String toString() {
return "User{" +
"id='" + id + '\'' +
", username='" + username + '\'' +
", roles=" + roles +
'}';
}
}
Role
@Setter
@Getter
@Entity
public class Role {
@Id
@GeneratedValue(strategy = GenerationType.AUTO)
private Integer id;
@Column(length = 30)
private String name;
@ManyToMany(cascade = CascadeType.REFRESH)
@JoinTable(name = "user_role",joinColumns = @JoinColumn(name = "role_id"),inverseJoinColumns = @JoinColumn(name="user_id"))
private Set<User> users;
public void addUser(User user){
this.users.add(user);
}
public void removeUser(User user){
this.users.remove(user);
}
}
注意@transaction的注解一定要加上。并且@Rollback(value = false) 也加上。springboot-test 默认在内存中save,不提交,所有以通过了但是数据库中无内容,官方说为了不影响上下文环境。
@Test
public void addRole(){
Role role = new Role();
role.setName("系统管理员");
roleRepository.save(role);
}
@Test
public void addUser() {
User user = new User();
user.setUsername("test1");
userRepostitory.save(user);
}
@Test
@Transactional
@Rollback(value = false)
public void addUserRole(){
User user = userRepostitory.findByUsername("test1");
Role role = roleRepository.getOne(1);
role.addUser(user);
roleRepository.saveAndFlush(role);
}
@Test
@Transactional
public void removeRoleUser(){
User user = userRepostitory.findByUsername("test1");
Role role = roleRepository.getOne(1);
role.removeUser(user);
roleRepository.saveAndFlush(role);
}
不能删除和添加成功,出现循环的主要问题在 toString()方法。此方法只能包含基本的元素,不要包含相应的@ManyToMany 的对象。两个类都是。这样才会ok.
@RunWith(SpringRunner.class)
@SpringBootTest
public class DemoBeetlApplicationTests {
@Autowired
private UserRepostitory userRepostitory;
@Autowired
private RoleRepository roleRepository;
@Autowired
private UserGroupRepository userGroupRepository;
@Autowired
private PriviledgeRepository priviledgeRepository;
@Autowired
private MenuRepository menuRepository;
@Autowired
private FileRepository fileRepository;
@Autowired
private ElementRepository elementRepository;
@Autowired
private OperationRepository operationRepository;
@Test
public void contextLoads() {
System.out.println("helle junit");
}
@Test
public void addRole(){
Role role = new Role();
role.setName("系统管理员");
roleRepository.save(role);
}
@Test
public void addUser() {
User user = new User();
user.setUsername("test1");
userRepostitory.save(user);
}
@Test
@Transactional
@Rollback(value = false)
public void addRoleUser(){
User user = userRepostitory.findByUsername("test1");
Role role = roleRepository.getOne(2);
role.addUser(user);
roleRepository.saveAndFlush(role);
}
@Test
@Transactional
@Rollback(value = false)
public void removeRoleUser(){
Role role = roleRepository.getOne(2);
User user = userRepostitory.findByUsername("test1");
role.removeUser(user);
roleRepository.saveAndFlush(role);
}
@Test
public void removeRole(){
Role role = roleRepository.getOne(2);
roleRepository.delete(role);
}
@Test
public void removeUser(){
Role role = roleRepository.getOne(2);
User user = userRepostitory.findByUsername("test1");
role.removeUser(user);
userRepostitory.delete(user);
}
配置JPA的时候多对多关系,报以下错误:
org.hibernate.AnnotationException: Illegal use of mappedBy on both sides of the relationship: com.csair.gme.core.domain.ComponentType.componentPropertys
不能两边都用mappedBy,只能用一边,而且用mappedBy的那一边是从表,另外一边就是主表。mappedBy=‘主表里的变量名'
以上为个人经验,希望能给大家一个参考,也希望大家多多支持编程网。
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本文标题: SpringBoot+JPA@ManyToMany的操作要点说明
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