SpringBoot + JPA @ManyToMany的操作要点说明

#不加这句则默认为myisam引擎
spring.jpa.database-platform=org.hibernate.dialect.MySQL5InnoDBDialect

@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 +
                '}';
    }
}

@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);
    }
}

   /**
     * 添加角色
     */
    @Test
    public void addRole(){
        Role role = new Role();
        role.setName("系统管理员");
        roleRepository.save(role);
    }
    /**
     * 添加用户
     */
    @Test
    public void addUser() {
        User user = new User();
        user.setUsername("test1");
        userRepostitory.save(user);
    }
    /**
     *
     * 通过关系维护方添加角色和用户的关系
     */
    @Test
    @Transactional
    @Rollback(value = false)
    public void  addUserRole(){
        User user = userRepostitory.findByUsername("test1");
        Role role = roleRepository.getOne(1);
        role.addUser(user);
        roleRepository.saveAndFlush(role);
    }
    /**
     *
     * 删除对应的关联数据
     */
    @Test
    @Transactional
    public void removeRoleUser(){
        User user = userRepostitory.findByUsername("test1");
        Role role = roleRepository.getOne(1);
        role.removeUser(user);
        roleRepository.saveAndFlush(role);
    }

@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");
    }
    /**
     * 添加角色
     */
    @Test
    public void addRole(){
        Role role = new Role();
        role.setName("系统管理员");
        roleRepository.save(role);
    }
    /**
     * 添加用户
     */
    @Test
    public void addUser() {
        User user = new User();
        user.setUsername("test1");
        userRepostitory.save(user);
    }
    /**
     *
     * 通过关系维护方添加角色和用户的关系
     *
     *
     */
    @Test
    @Transactional
    @Rollback(value = false)
    public void  addRoleUser(){
        User user = userRepostitory.findByUsername("test1");
        Role role = roleRepository.getOne(2);
        role.addUser(user);
        roleRepository.saveAndFlush(role);
    }
    /**
     *
     * 删除对应的关联数据
     */
    @Test
    @Transactional
    @Rollback(value = false)
    public void removeRoleUser(){
        Role role = roleRepository.getOne(2);
        User user = userRepostitory.findByUsername("test1");
        role.removeUser(user);
        roleRepository.saveAndFlush(role);
    }
    /**
     *
     * 删除单一的角色是可以删除相应的关系
     */
    @Test
    public void removeRole(){
        Role role = roleRepository.getOne(2);
        roleRepository.delete(role);
    }
    /**
     *
     * 删除用户不能联动删除关系,
     * 这个时不能执行的，只能在数据维护端来进行删除后，在进行相应的用户删除。
     *
     */
    @Test
    public  void removeUser(){
        Role role = roleRepository.getOne(2);
        User user = userRepostitory.findByUsername("test1");
        role.removeUser(user);
        userRepostitory.delete(user);
    }