英文:
Is there a simple implementation of HATEOAS + Pagination in Spring without data rest?
问题
以下是您提供的内容的翻译部分:
{
"_links": {
"first": {
"href": "http://localhost:8080/api/albums-list?page=0&size=2&sort=title,desc"
},
"prev": {
"href": "http://localhost:8080/api/albums-list?page=0&size=2&sort=title,desc"
},
"self": {
"href": "http://localhost:8080/api/albums-list?page=1&size=2&sort=title,desc"
},
"next": {
"href": "http://localhost:8080/api/albums-list?page=2&size=2&sort=title,desc"
},
"last": {
"href": "http://localhost:8080/api/albums-list?page=4&size=2&sort=title,desc"
}
},
"page": {
"size": 2,
"totalElements": 10,
"totalPages": 5,
"number": 1
},
"_embedded": {
"albums": [
{
"id": 7,
"title": "Top Hits Vol 7",
"description": "Top hits vol 7. description",
"releaseDate": "10-03-1987",
"actors": [
{
"id": 4,
"firstName": "Janice",
"lastName": "Preston",
"_links": {
"self": {
"href": "http://localhost:8080/api/actors/4"
}
}
}
],
"_links": {
"self": {
"href": "http://localhost:8080/api/actors/7"
}
}
},
{
"id": 6,
"title": "Top Hits Vol 6",
"description": "Top hits vol 6. description",
"releaseDate": "10-03-1986",
"actors": [
{
"id": 3,
"firstName": "Laverne",
"lastName": "Mann",
"_links": {
"self": {
"href": "http://localhost:8080/api/actors/3"
}
}
}
],
"_links": {
"self": {
"href": "http://localhost:8080/api/actors/6"
}
}
}
]
}
}
请注意,这是您提供的内容的翻译版本,仅包含原始内容的翻译,没有附加的回答或解释。如果您有任何其他翻译需求,请随时提问。
英文:
I've been searching for a few days on how to implement a Spring REST API containing HATEOAS links + Pagination with Spring boot and JPA (No spring data rest) like this random example:
{
"_links": {
"first": {
"href": "http://localhost:8080/api/albums-list?page=0&size=2&sort=title,desc"
},
"prev": {
"href": "http://localhost:8080/api/albums-list?page=0&size=2&sort=title,desc"
},
"self": {
"href": "http://localhost:8080/api/albums-list?page=1&size=2&sort=title,desc"
},
"next": {
"href": "http://localhost:8080/api/albums-list?page=2&size=2&sort=title,desc"
},
"last": {
"href": "http://localhost:8080/api/albums-list?page=4&size=2&sort=title,desc"
}
},
"page": {
"size": 2,
"totalElements": 10,
"totalPages": 5,
"number": 1
},
"_embedded": {
"albums": [
{
"id": 7,
"title": "Top Hits Vol 7",
"description": "Top hits vol 7. description",
"releaseDate": "10-03-1987",
"actors": [
{
"id": 4,
"firstName": "Janice",
"lastName": "Preston",
"_links": {
"self": {
"href": "http://localhost:8080/api/actors/4"
}
}
}
],
"_links": {
"self": {
"href": "http://localhost:8080/api/actors/7"
}
}
},
{
"id": 6,
"title": "Top Hits Vol 6",
"description": "Top hits vol 6. description",
"releaseDate": "10-03-1986",
"actors": [
{
"id": 3,
"firstName": "Laverne",
"lastName": "Mann",
"_links": {
"self": {
"href": "http://localhost:8080/api/actors/3"
}
}
}
],
"_links": {
"self": {
"href": "http://localhost:8080/api/actors/6"
}
}
}
]
}
}
However, the solutions that I've found so far are ridiculously complicated or the amount of boilerplate are laughable
This solution for instance:
https://howtodoinjava.com/spring5/hateoas/pagination-links/
the tutorial on the page doesn't present it entirely but it requires you to create the entity, a model for the entity, and a long RepresentationModelAssemblerSupport full of boilerplate
I've tried this also:
https://spring.io/guides/tutorials/rest/
However the nested classes (i have relations of one to many/many to one) don't get the links for HATEOAS:
{
"id": 3,
"nome": "Amazonas",
"uf": "AM",
"cidades": [
{
//no HATEOAS in here
"id": 10003,
"nome": null,
"instituicoes": [],
"uf": "AM"
},
{
"id": 219,
"nome": "Alvarães",
"instituicoes": [],
"uf": "AM"
}
],
"_links": {
"self": {
"href": "http://localhost:8080/api/v1/estados/estadoes/3"
},
"estadoes": {
"href": "http://localhost:8080/api/v1/estados/estadoes"
}
}
}
I mean, isn't there a simpler solution? Luckily for pagination PagingAndSortingRepository is useful but then having both pagination + HATEOAS, what a nightmare.
答案1
得分: 10
`RepresentationModelAssembler`是必需的。如果不需要额外的字段,那么一个模型类`extends EntityModel<T>`是不必要的。
我的示例实体类是`Inventory`。
RepresentationModelAssembler。你可以在这里添加更多链接。
```java
@Component
public class InventoryModelAssembler implements RepresentationModelAssembler<Inventory, EntityModel<Inventory>> {
@Override
public EntityModel<Inventory> toModel(Inventory inventory) {
return EntityModel.of(inventory,
linkTo(methodOn(InventoryController.class).get(inventory.getId()))
.withSelfRel());
}
}
控制器
@RestController
@RequestMapping("/inventories")
@RequiredArgsConstructor
public class InventoryController {
private final InventoryRepository inventoryRepository;
private final PagedResourcesAssembler pagedResourcesAssembler;
private final InventoryModelAssembler inventoryModelAssembler;
@GetMapping
public ResponseEntity get(Pageable pageable) {
Page<Inventory> inventories = inventoryRepository.findAll(pageable);
return ResponseEntity
.ok()
.contentType(MediaTypes.HAL_JSON)
.body(pagedResourcesAssembler.toModel(inventories, inventoryModelAssembler));
}
}
HAL JSON 响应。完整的长响应可以在我的HTML文档中找到。下载并在浏览器中打开。
{
"_embedded" : {
"inventories" : [ {
"carrier" : "SG",
"fltNum" : "001",
"serviceType" : "PAX",
"fltDate" : "2020-01-20",
"fltDow" : 1,
"createdDate" : "2020-06-11T13:21:44.992Z",
"lastModifiedDate" : "2020-06-11T13:21:44.992Z",
"_links" : {
"self" : {
"href" : "http://localhost:8080/inventories/5ee22fe8853b0f45ae5fca27"
}
}
}]
},
"_links" : {
"first" : {
"href" : "http://localhost:8080/inventories?carrier=SG&fltNum=001&page=0&size=10&sort=fltNum,asc&sort=fltDate,desc"
},
"self" : {
"href" : "http://localhost:8080/inventories?carrier=SG&fltNum=001&page=0&size=10&sort=fltNum,asc&sort=fltDate,desc"
},
"next" : {
"href" : "http://localhost:8080/inventories?carrier=SG&fltNum=001&page=1&size=10&sort=fltNum,asc&sort=fltDate,desc"
},
"last" : {
"href" : "http://localhost:8080/inventories?carrier=SG&fltNum=001&page=1&size=10&sort=fltNum,asc&sort=fltDate,desc"
}
},
"page" : {
"size" : 10,
"totalElements" : 20,
"totalPages" : 2,
"number" : 0
}
}
完整代码在GitHub上共享。如果我的项目对您有帮助,不仅限于这个答案,请考虑在GitHub上为它点赞。
英文:
A RepresentationModelAssembler
is required. A model class extends EntityModel<T>
is unnecessary if you don't need additional fields.
My example entity class is Inventory
.
RepresentationModelAssembler. You can add more links here.
@Component
public class InventoryModelAssembler implements RepresentationModelAssembler<Inventory, EntityModel<Inventory>> {
@Override
public EntityModel<Inventory> toModel(Inventory inventory) {
return EntityModel.of(inventory,
linkTo(methodOn(InventoryController.class).get(inventory.getId()))
.withSelfRel());
}
}
Controller
@RestController
@RequestMapping("/inventories")
@RequiredArgsConstructor
public class InventoryController {
private final InventoryRepository inventoryRepository;
private final PagedResourcesAssembler pagedResourcesAssembler;
private final InventoryModelAssembler inventoryModelAssembler;
@GetMapping
public ResponseEntity get(Pageable pageable) {
Page<Inventory> inventories = inventoryRepository.findAll(pageable);
return ResponseEntity
.ok()
.contentType(MediaTypes.HAL_JSON)
.body(pagedResourcesAssembler.toModel(inventories, inventoryModelAssembler));
}
}
HAL JSON response. A full long response can be found in my HTML doc. Download it and open with your browser.
{
"_embedded" : {
"inventories" : [ {
"carrier" : "SG",
"fltNum" : "001",
"serviceType" : "PAX",
"fltDate" : "2020-01-20",
"fltDow" : 1,
"createdDate" : "2020-06-11T13:21:44.992Z",
"lastModifiedDate" : "2020-06-11T13:21:44.992Z",
"_links" : {
"self" : {
"href" : "http://localhost:8080/inventories/5ee22fe8853b0f45ae5fca27"
}
}
}]
},
"_links" : {
"first" : {
"href" : "http://localhost:8080/inventories?carrier=SG&fltNum=001&page=0&size=10&sort=fltNum,asc&sort=fltDate,desc"
},
"self" : {
"href" : "http://localhost:8080/inventories?carrier=SG&fltNum=001&page=0&size=10&sort=fltNum,asc&sort=fltDate,desc"
},
"next" : {
"href" : "http://localhost:8080/inventories?carrier=SG&fltNum=001&page=1&size=10&sort=fltNum,asc&sort=fltDate,desc"
},
"last" : {
"href" : "http://localhost:8080/inventories?carrier=SG&fltNum=001&page=1&size=10&sort=fltNum,asc&sort=fltDate,desc"
}
},
"page" : {
"size" : 10,
"totalElements" : 20,
"totalPages" : 2,
"number" : 0
}
}
Full code is shared in Github. If my project is helpful other than this answer, consider give it a star in Github.
答案2
得分: 0
这个例子中有一个很好的解释,附带有代码。
Pagination(with Hateoas), Filtering & Sorting with Spring Boot and JPA
演示了多种方法。这正好涵盖了在没有使用Spring Data Rest的情况下实现分页、排序和过滤的方法。
英文:
There is an excellent explanation here in this example with code
Pagination(with Hateoas), Filtering & Sorting with Spring Boot and JPA
Multiple approaches are demonstrated. This covers exactly the appraoch to implement pagination, including sorting and filtering without spring data rest.
通过集体智慧和协作来改善编程学习和解决问题的方式。致力于成为全球开发者共同参与的知识库,让每个人都能够通过互相帮助和分享经验来进步。
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