OffsetDateTime 产生“未找到类型为 public javax.ws.rs.core.response 的参数的注入源"；在 GET 方法中

问题描述

我有以下 GET REST 方法:

I have the following GET REST method:

import java.time.OffsetDateTime;

import javax.ws.rs.Consumes;
import javax.ws.rs.DELETE;
import javax.ws.rs.GET;
import javax.ws.rs.HeaderParam;
import javax.ws.rs.POST;
import javax.ws.rs.PUT;
import javax.ws.rs.Path;
import javax.ws.rs.PathParam;
import javax.ws.rs.Produces;
import javax.ws.rs.QueryParam;
import javax.ws.rs.core.Response;

import io.swagger.annotations.Api;
import io.swagger.annotations.ApiOperation;
import io.swagger.annotations.ApiResponse;
import io.swagger.annotations.ApiResponses;
import com.product.rest.api.TransactionsApi;
import com.product.rest.model.Transaction;

@Path("/transactions")

@Api(description = "the transactions API")
@Consumes({ "application/json" })
@Produces({ "application/json" })
public class TransactionsApiImpl extends TransactionsApi {

    @GET

    @Consumes({ "application/json" })
    @Produces({ "application/json" })
    @ApiOperation(value = "", notes = "Get all transactions", response =     Transaction.class, responseContainer = "List", tags = {})
    @ApiResponses(
        value = { @ApiResponse(code = 200, message = "OK", response =     Transaction.class, responseContainer = "List"),
            @ApiResponse(code = 400, message = "Bad Request", response =     Transaction.class, responseContainer = "List"),
            @ApiResponse(code = 404, message = "Not Found", response =     Transaction.class, responseContainer = "List"),
            @ApiResponse(code = 500, message = "Internal Server Error",     response = Transaction.class, responseContainer = "List") })
    @Override
    public Response transactionsGet(
        @HeaderParam("tok") String tok,
        @QueryParam("param1") Integer param1,
        @QueryParam("param2") String param2,
        @QueryParam("param3") OffsetDateTime param3,
        @QueryParam("param4") OffsetDateTime param4,
        @QueryParam("param5") Integer param5,
        @QueryParam("param6") Integer param6,
        @QueryParam("param7") String param7) {
        return Response.ok().entity("Success!").build();
    }

TransactionsApi 是使用 Swagger Codegen 生成的实现，Transaction 模型类也是如此.我在这个类中还有其他几个函数，但是每当我不注释 GET/transactions 函数时，我都会收到以下错误:

The TransactionsApi is a generated implementation using Swagger Codegen, as is the Transaction model class. I have several other functions in this class, but whenever I leave the GET /transactions function uncommented, I receive the following error:

WARN [Thread-1] (ContextHandler.java:2175) - unavailable
org.glassfish.jersey.server.model.ModelValidationException: Validation of the application resource model has failed during application initialization.

[[FATAL] No injection source found for a parameter of type public javax.ws.rs.core.Response
com.product.rest.impl.v1.TransactionsApiImpl.transactionsGet(java.lang.String,java.lang.Integer,java.lang.String,java.time.OffsetDateTime,java.time.OffsetDateTime,java.lang.Integer,java.lang.Integer,java.lang.String) at index 3.; source='ResourceMethod{httpMethod=GET, consumedTypes=[application/json], producedTypes=[application/json], suspended=false, suspendTimeout=0, suspendTimeoutUnit=MILLISECONDS, invocable=Invocable{handler=ClassBasedMethodHandler{handlerClass=class com.product.rest.impl.v1.TransactionsApiImpl, handlerConstructors=[org.glassfish.jersey.server.model.HandlerConstructor@7df78e88]}, definitionMethod=public javax.ws.rs.core.Response

我发现的所有其他类似问题都与 MultiPart Data 和文件上传有关，而我正在发出一个简单的 GET 请求.其他同样使用javax.ws.rs.code.Response类的函数没有这个问题，服务器正常启动.

All other similar questions I have found had to do with MultiPart Data and file uploading, whereas I am making a simple GET request. Other functions that also use the javax.ws.rs.code.Response class do not have this issue and the server starts normally.

我注意到只要 OffsetDateTime 类在参数中(即 param3 和 param4)就会出现问题，但我一直无法找出原因.此外，OffsetDateTime 是由 Swagger Codegen 选择的，我不愿意更改它，看看我以后每次重新生成源时都必须更改每个派生文件.

I have noticed that the problem happens whenever the OffsetDateTime class is in the parameters (i.e. param3 and param4), but I have been unable to find out why. Moreover, OffsetDateTime was chosen by Swagger Codegen and I am reluctant to change it seeing how I will have to change every derived file afterwards whenever I regenerate my sources.

有没有人在使用 REST 服务和 OffsetDateTime 之前遇到过这个问题?

Has anyone had this issue before with REST services and OffsetDateTime?

推荐答案

有关系.该错误是您在 Jersey 无法验证资源模型时遇到的一般错误.资源模型的一部分是方法参数.Jersey 有一个系统可以知道哪些参数可以处理，哪些不能处理.在您的情况下，它不知道如何处理 OffsetDateTime.

It's related. The error is a general error you get when Jersey can't validate the resource model. Part of the resource model is the method parameters. Jersey has a system for knowing which parameters it will be able to process and which ones it won't. In your case, it doesn't know how to process the OffsetDateTime.

为了能够将非基本类型用作@QueryParams(以及所有其他 @XxxParams，例如 @PathParam 和@FormParam 等):

There are a set of rules that you need to follow in order to able to use non basic types as @QueryParams (and all other @XxxParams such as @PathParam and @FormParam, etc.):

1. 成为原始类型
2. 有一个接受单个 String 参数的构造函数
3. 有一个名为 valueOf 或 fromString 的静态方法，它接受单个字符串参数(例如，请参见 Integer.valueOf(String))
4. 拥有 ParamConverterProvider JAX-RS 扩展 SPI 的注册实现，它返回一个能够对类型进行从字符串"转换的 ParamConverter 实例.
5. 成为 List、Set 或 SortedSet，其中 T 满足2、3 或 4 以上.生成的集合是只读的.

1. Be a primitive type
2. Have a constructor that accepts a single String argument
3. Have a static method named valueOf or fromString that accepts a single String argument (see, for example, Integer.valueOf(String))
4. Have a registered implementation of ParamConverterProvider JAX-RS extension SPI that returns a ParamConverter instance capable of a "from string" conversion for the type.
5. Be List<T>, Set<T> or SortedSet<T>, where T satisfies 2, 3 or 4 above. The resulting collection is read-only.

所以在这个 OffsetDateTime 的例子中，沿着列表往下走；它不是原始的；它没有 String 构造函数；它没有静态的 valueOf 或 fromString

So in this case of OffsetDateTime, going down the list; it's not a primitive; it doesn't have a String constructor; it doesn't have a static valueOf or fromString

所以基本上，剩下的唯一选择就是为它实现一个 ParamConverter/ParamConverterProvider.基本设置如下

So basically, the only option left is to implement a ParamConverter/ParamConverterProvider for it. The basic set up looks like

@Provider
public class OffsetDateTimeProvider implements ParamConverterProvider {

    @Override
    public <T> ParamConverter<T> getConverter(Class<T> clazz, Type type, Annotation[] annotations) {
        if (clazz.getName().equals(OffsetDateTime.class.getName())) {

            return new ParamConverter<T>() {

                @SuppressWarnings("unchecked")
                @Override
                public T fromString(String value) {
                    OffsetDateTime time = ...
                    return (T) time;
                }

                @Override
                public String toString(T time) {
                    return ...;
                }
            };
        }
        return null;
    }
}

Jersey 将向您传递查询参数的 String 值，您的工作是创建它并返回它.

Jersey will pass you the String value of the query parameter, and it's your job to to create it and return it.

然后只需向应用程序注册 OffsetDateTimeProvider.如果您使用包扫描，则应从 @Provider 注释中自动获取并注册.

Then just register the OffsetDateTimeProvider with the application. If you're using package scanning, it should be picked up and registered automatically from the @Provider annotation.

我不使用 Swagger，所以我不知道他们是否已经提供了已经实现的类似的东西，但他们会为你生成这个似乎很奇怪，而且没有办法让它工作.我知道 Jersey 3 将支持 Java 8，但谁知道什么时候会发布.

I don't use Swagger, so I don't know if they already provide something like this already implemented, but it seems odd that they would generate this for you, and not have a way to make it work. I know Jersey 3 will have Java 8 support out the box, but who know when the heck that's gonna be released.

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