我正在使用Spring HATEOAS 0.20（也尝试过0.23），当返回单个对象与返回对象数组时，出现了非常奇怪的行为。当返回单个对象时，生成的JSON会返回按照HAL规范格式化的HATEOAS链接（即"_links"），而我不希望这样。
{
"_Id": 161,
...
"_links": {
"self": {
"href": "http://localhost:8080/library/161"
}
}
}
在返回对象数组时，生成的 JSON 以规范格式返回 HATEOAS 链接（即“links”），这正是我所需要的。
[
{
"_Id": 277,
...
"links": [
{
"rel": "self",
"href": "http://localhost:8080/library/277"
}
]
}
]
我没有指定@EnableHypermediaSupport，所以不应该支持HAL。但是，当返回单个对象时，我仍然得到了HAL格式。
有人知道这是为什么吗？如何按照HATEOAS规范返回带有HATEOAS链接的单个对象？
===== 根据请求添加更多信息的更新 =====
如果使用以下代码返回JSON负载，则会获得HAL链接：
//
//------------------- Get Single Membership As Single Object ----------------------------------------------
//
@PreAuthorize("hasRole('ROLE_ADMIN')")
@RequestMapping(value = REQUEST_GET_MEMBERSHIP, method = RequestMethod.GET, produces = { MediaType.APPLICATION_JSON_VALUE })
public ResponseEntity<MembershipResource> getMembership(@PathVariable("membership-id") Integer membershipId) {
Membership membership = membershipRepository.findOne(membershipId);
if (membership == null) {
HttpHeaders headers = new HttpHeaders();
headers.add("error", "Membership with ID of " + membershipId + " does not exist.");
return new ResponseEntity<MembershipResource>(headers, HttpStatus.NOT_FOUND);
}
MembershipResourceAssembler assm = new MembershipResourceAssembler();
MembershipResource membershipResource = assm.toResource(membership);
System.out.println("membership id: " + membership.getId());
return new ResponseEntity<MembershipResource>(membershipResource, HttpStatus.OK);
}
以上将生成HAL规范风格的链接：
{
"_Id": 277,
"member": {
"_Id": 112,
"title": "Mr.",
"firstName": "ABC",
"middleName": "",
"lastName": "XYZ",
"active": true,
"_links": {
"self": {
"href": "http://localhost:8080/members/112"
}
}
},
"membershipTermType": "2016",
"card": {
"_Id": 27,
"name": "27",
"graphicUrl": "",
"number": 27,
},
"active": false,
"paid": true,
"renewal": true,
"termsAndConditionsAcknowledged": true,
"_links": {
"self": {
"href": "http://localhost:8080/memberships/277"
}
}
}
如果我修改方法以返回单个成员的列表，则返回的JSON负载将具有HATEOAS规范链接:
//
//------------------- Get Single Membership As List --------------------------------------------------------
//
@PreAuthorize("hasRole('ROLE_ADMIN')")
@RequestMapping(value = REQUEST_GET_MEMBERSHIP, method = RequestMethod.GET, produces = { MediaType.APPLICATION_JSON_VALUE })
public ResponseEntity<List<MembershipResource>> getMembership(@PathVariable("membership-id") Integer membershipId) {
Membership membership = membershipRepository.findOne(membershipId);
if (membership == null) {
HttpHeaders headers = new HttpHeaders();
headers.add("error", "Membership with ID of " + membershipId + " does not exist.");
return new ResponseEntity<List<MembershipResource>>(headers, HttpStatus.NOT_FOUND);
}
MembershipResourceAssembler assm = new MembershipResourceAssembler();
MembershipResource membershipResource = assm.toResource(membership);
ArrayList<MembershipResource> list = new ArrayList<MembershipResource>();
list.add(membershipResource);
System.out.println("membership id: " + membership.getId());
return new ResponseEntity<List<MembershipResource>>(list, HttpStatus.OK);
}
上述内容将生成符合HATEOAS规范的链接：
[
{
"_Id": 277,
"member": {
"_Id": 112,
"title": "Mr.",
"firstName": "ABC",
"middleName": "",
"lastName": "XYZ",
"active": true,
"links": [
{
"rel": "self",
"href": "http://localhost:8080/members/112"
}
]
},
"membershipTermType": "2016",
"card": {
"_Id": 27,
"name": "27",
"graphicUrl": "",
"number": 27,
"links": []
},
"active": false,
"renewal": true,
"paid": true,
"termsAndConditionsAcknowledged": true,
"links": [
{
"rel": "self",
"href": "http://localhost:8080/memberships/277"
}
]
}
]
有人知道为什么会发生这种情况吗？ 按照HATEOAS规范返回带有HATEOAS链接的单个对象需要做些什么？
ResourceSupport，而另一个实例没有（只返回了一个List）。你使用Spring Boot吗？ - a better oliver@EnableAutoConfiguration(exclude = HypermediaAutoConfiguration.class)或在属性文件中添加spring.hateoas.use-hal-as-default-json-media-type=false。 - a better oliver@EnableAutoConfiguration(exclude = HypermediaAutoConfiguration.class)做到了！感谢 @zeroflagL - shermantech