关于SpringDataJPA和MapStruct的使用

Question

我使用SpringDataJpa进行多表关联,其中几个实体类的对应情况如下:

User:

public class User extends BaseEntity  {
 private String username;
 private String password;
 @ManyToOne ( cascade = CascadeType.ALL, fetch = FetchType.LAZY )
 @JoinColumn ( name = "dept_id" )
 private Department depts;
 @ManyToOne ( cascade = CascadeType.ALL, fetch = FetchType.LAZY )
 @JoinColumn ( name = "role_id" )
 private Role role;
}

Role :

public class Role extends BaseEntity {
 private String role;
 private String roleName;
 @OneToMany (mappedBy = "roles",cascade=CascadeType.ALL,fetch=FetchType.LAZY)
 private Set<User> users;
 @ManyToMany (mappedBy = "roles",cascade=CascadeType.ALL,fetch=FetchType.EAGER)
 @JoinTable(name = "t_role_route",joinColumns=@JoinColumn(name="role_id",referencedColumnName = "id"),inverseJoinColumns = @JoinColumn(name = "route_id"))
 @JsonIgnore
 private Set<Route> routes;
 @ManyToOne ( cascade = CascadeType.ALL, fetch = FetchType.LAZY )
 @JoinColumn ( name = "dept_id" )
 private Department depts;
}

Route:

public class Route extends BaseEntity {
 private String route;
 private String routeName;
 @ManyToMany(mappedBy = "routes")
 private Set<Role> roles;
}

Department:

public class Department extends BaseEntity {
 private String deptName;
 private String dept;
 @OneToMany (mappedBy = "depts",cascade= CascadeType.ALL,fetch= FetchType.LAZY)
 private Set<User> users;
 @OneToMany (mappedBy = "depts",cascade=CascadeType.ALL,fetch=FetchType.LAZY)
 private Set<Role> roles;
}

现在我在登录后想返回这么一个对象:
UserVo:

private String username;
private String password;
private List<String> routes;
private List<String> routeNames;
private String deptName;
private String dept;
private Collection<? extends GrantedAuthority> authorities;

其中routes和routeNames是role中routes的属性,deptName和dept是user中dept的属性,现在我想在用户登陆的时候根据username 从数据库查询到user以及关联的信息,并且使用mapStruct进行转换成userVO,请问这个该怎么转化呢?

Answer 1

最近项目上使用了MapStruct，开始感觉一般，使用久了有点舒服了，感觉掌握了不少，跑来Segmentfault上挑战一下，哈哈哈，就搜到这个问题，有点挖坟的亚子

直接上结果，大概应该这么写吧

    @Mapping(source = "role.routes", target = "routes")
    @Mapping(source = "role.routes", target = "routeNames", qualifiedByName = "routeSetToRouteNames")
    @Mapping(source = "depts.dept", target = "dept")
    @Mapping(source = "depts.deptName", target = "deptName")
    UserVo userToUserVo(User user);

    default List<String> routeSetToRouteList(Set<Route> routes) {
        return routes.stream().map(Route::getRoute).collect(Collectors.toList());
    }

    @Named(value = "routeSetToRouteNames")
    default List<String> routeSetToRouteNames(Set<Route> routes) {
        return routes.stream().map(Route::getRouteName).collect(Collectors.toList());
    }

当然最后一个字段authorities题主没有提怎么赋值，我也就没看了

这其中有个小难点，就是Set<Route>转routes和Set<Route>转routeNames，不加@Named限定，会报错

Ambiguous mapping methods found for mapping property xxx

因为他们的入参和出参类型是一样，所以MapStruct会判断不出该选哪个映射方法，因此需要用@Named做一个方法的名称限定，简单理解为取个名字，然后在特定的@Mapping选择限定的映射方法，参见官方文档其中Example 49和Example 50

大概是这样吧~仅供参考...当然可能参考都用不上，都这么久了，要不然题主自己写出来了，要不然直接手动映射，放弃MapStruct了...只当给以后来搜类似问题的人一点小小的参考叭！