Spring Boot 2.3模糊映射

Question

我有一个带有两个endpoint的spring控制器，当访问它们时，它们会返回任意方法异常。我试图使用HeaderContentNegotiationStrategy来区分它们，它查看传入请求的Accept标头，以确定将请求映射到哪个方法。据我所知，这种策略应该将传入的accept头与products符号进行比较。在我的情况下，这两种方法都会生成一个应用程序/json媒体类型，但是Spring还允许您提供一个consumes，我读取它们的文档时，还应该让内容协商查看请求的内容类型头来映射该方法。

我的问题是，在进行映射时，如何让内容协商也查看内容类型头？如果您无法让内容谈判者查看consumes符号，为什么会有？有什么意义？

控制器：

@ResourcePayloadOverride(action = ActionTypes.READ)
@CustomPermission(Permission.READ)
@RequestMapping(method = RequestMethod.POST,
        produces = { MediaType.APPLICATION_JSON_VALUE, ResourceCollection.MEDIA_TYPE_JSON_VALUE },
        consumes = MediaType.TEXT_PLAIN_VALUE)
public ResponseEntity<ResourceCollection<Class1>> method1(
        @PathVariable(value="param_1") String param1,
        @RequestParam(value="param_2", required=false) long param2,
        @RequestParam(value="param_3", required=false) int param3,
        @RequestParam(value="param_4", required=false) String param4,
        @RequestBody(required=false) String body) {
    [...]
}

@RequestMapping(method = { RequestMethod.POST },
        produces = { MediaType.APPLICATION_JSON_VALUE, Class1.MEDIA_TYPE_JSON_VALUE },
        consumes = { Class1.MEDIA_TYPE_JSON_VALUE, Class2.MEDIA_TYPE_JSON_VALUE, MediaType.APPLICATION_JSON_VALUE})
public ResponseEntity<Class1> post(
        @PathVariable("param1") String param1,
        @RequestParam(value="param2", required = false) String param2,
        @RequestParam(value="param3", required = false) String param3,
        @RequestParam(value="param4", required = false) String param4,
        @RequestBody(required=false) String noop) //Actually needed!!!
{
    [...]
}

错误：

{"version":1,"timeStamp":"2021-05-13T16:30:33.785Z","level":"error","source":"","message":"java.lang.IllegalStateException: Ambiguous handler methods mapped for '/{my_endpoint}': {public org.springframework.http.ResponseEntity {myPackage.class}.method1(java.lang.String,long,int,java.lang.String,java.lang.String), public org.springframework.http.ResponseEntity {myPackage.class}.post(java.lang.String,java.lang.String,java.lang.String,java.lang.String,java.lang.String)}","messageParameters":{"0":"java.lang.IllegalStateException","1":"Ambiguous handler methods mapped for '/{my_endpoint}': {public org.springframework.http.ResponseEntity {myPackage.class}.method1(java.lang.String,long,int,java.lang.String,java.lang.String), public org.springframework.http.ResponseEntity {myPackage.class).post(java.lang.String,java.lang.String,java.lang.String,java.lang.String,java.lang.String)}"

我在这里用虚拟值替换了许多细节，但我不认为这会影响更大的问题

Answer 1

简化问题：根据消耗区分endpoint

import org.springframework.web.bind.annotation.RequestParam;

@RestController
class ConsumeController {
    @PostMapping(value = "/post", consumes = MediaType.APPLICATION_JSON_VALUE)
    public String postJson(@RequestBody(required = false) String data) {
        return "json: " + data;
    }

    @PostMapping(value = "/post", consumes = MediaType.TEXT_PLAIN_VALUE)
    public String postText(@RequestBody(required = false) String data) {
        return "text: " + data;
    }
}

这将在实际提供数据时达到预期效果：

curl -d "{'x':'y'}" -H "Content-Type:application/json" -X POST http://localhost:8080/post
json: {'x':'y'}

curl -d "hello" -H "Content-Type:text/plain" -X POST http://localhost:8080/post
text: hello

但如果不发送数据，这将不起作用：

curl -H "Content-Type:application/json" -X POST http://localhost:8080/post
{...error: Ambiguous handler methods mapped for '/post'}

当没有可消费的内容时，无法区分请求。。。

可能的解决方法：

• 将数据设为所需的RequestBody（required=true）字符串数据，并处理空数据
• 使用额外的头使endpoint唯一，如PostMapping（value=“/post”，consumes=MediaType.TEXT\u PLAIN\u value，headers=“allow=TEXT”）

curl -H "Content-Type:text/plain" -H "allow:text"  -X POST http://localhost:8080/post
text: null