如何在 Jersey Client 中引发自定义异常？

Question

我正在通过我的项目 "shop" 学习 Jersey 和 JAX-RS 2.x。我希望我的客户端 SDK 在 HTTP 响应为 4xx 或 5xx 时引发 ShopException。这是我尝试过的——在客户端构建器中注册一个 ClientResponseFilter：

target =
    ClientBuilder.newBuilder()
        .register(ShopApplication.newJacksonJsonProvider())
        .register((ClientResponseFilter) (requestCtx, responseCtx) -> {
          if (responseCtx instanceof ClientResponse) {
            ClientResponse resp = (ClientResponse) responseCtx;
            if (resp.getStatus() >= 400) {
              ShopExceptionData data = resp.readEntity(ShopExceptionData.class);
              throw new ShopException(resp.getStatus(), data);
            }
          }
        })
        .build()
        .target(Main.BASE_URI.resolve("products"));

测试看起来像：

@Test
public void getProduct_invalidId() {
  try {
    target.path("123!").request(APPLICATION_JSON).get(Product.class);
    fail("GET should raise an exception");
  } catch (ShopException e) {
    assertThat(e.getData().getErrorCode()).isEqualTo(ShopError.PRODUCT_ID_INVALID.code);
    assertThat(e.getData().getErrorMessage()).isEqualTo(ShopError.PRODUCT_ID_INVALID.message);
  }
}

问题是，我定制的 ShopException 被 Jersey 捕获并包裹成 javax.ws.rs.ProcessingException:

javax.ws.rs.ProcessingException
    at org.glassfish.jersey.client.ClientRuntime.invoke(ClientRuntime.java:287)
    at org.glassfish.jersey.client.JerseyInvocation.lambda$invoke(JerseyInvocation.java:767)
    at org.glassfish.jersey.internal.Errors.process(Errors.java:316)
    at org.glassfish.jersey.internal.Errors.process(Errors.java:298)
    at org.glassfish.jersey.internal.Errors.process(Errors.java:229)
    at org.glassfish.jersey.process.internal.RequestScope.runInScope(RequestScope.java:414)
    at org.glassfish.jersey.client.JerseyInvocation.invoke(JerseyInvocation.java:765)
    at org.glassfish.jersey.client.JerseyInvocation$Builder.method(JerseyInvocation.java:428)
    at org.glassfish.jersey.client.JerseyInvocation$Builder.get(JerseyInvocation.java:324)
    at io.mincong.shop.rest.ProductResourceIT.getProduct_invalidId(ProductResourceIT.java:64)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.lang.reflect.Method.invoke(Method.java:498)
    at org.junit.runners.model.FrameworkMethod.runReflectiveCall(FrameworkMethod.java:50)
    at org.junit.internal.runners.model.ReflectiveCallable.run(ReflectiveCallable.java:12)
    at org.junit.runners.model.FrameworkMethod.invokeExplosively(FrameworkMethod.java:47)
    at org.junit.internal.runners.statements.InvokeMethod.evaluate(InvokeMethod.java:17)
    at org.junit.internal.runners.statements.RunBefores.evaluate(RunBefores.java:26)
    at org.junit.internal.runners.statements.RunAfters.evaluate(RunAfters.java:27)
    at org.junit.runners.ParentRunner.runLeaf(ParentRunner.java:325)
    at org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:78)
    at org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:57)
    at org.junit.runners.ParentRunner.run(ParentRunner.java:290)
    at org.junit.runners.ParentRunner.schedule(ParentRunner.java:71)
    at org.junit.runners.ParentRunner.runChildren(ParentRunner.java:288)
    at org.junit.runners.ParentRunner.access[=12=]0(ParentRunner.java:58)
    at org.junit.runners.ParentRunner.evaluate(ParentRunner.java:268)
    at org.junit.runners.ParentRunner.run(ParentRunner.java:363)
    at org.junit.runner.JUnitCore.run(JUnitCore.java:137)
    at com.intellij.junit4.JUnit4IdeaTestRunner.startRunnerWithArgs(JUnit4IdeaTestRunner.java:68)
    at com.intellij.rt.execution.junit.IdeaTestRunner$Repeater.startRunnerWithArgs(IdeaTestRunner.java:47)
    at com.intellij.rt.execution.junit.JUnitStarter.prepareStreamsAndStart(JUnitStarter.java:242)
    at com.intellij.rt.execution.junit.JUnitStarter.main(JUnitStarter.java:70)
Caused by: io.mincong.shop.rest.ShopException
    at io.mincong.shop.rest.ProductResourceIT.lambda$setUp[=12=](ProductResourceIT.java:42)
    at org.glassfish.jersey.client.ClientFilteringStages$ResponseFilterStage.apply(ClientFilteringStages.java:133)
    at org.glassfish.jersey.client.ClientFilteringStages$ResponseFilterStage.apply(ClientFilteringStages.java:121)
    at org.glassfish.jersey.process.internal.Stages.process(Stages.java:171)
    at org.glassfish.jersey.client.ClientRuntime.invoke(ClientRuntime.java:283)
    ... 33 more

是否有解决方法来避免 ProcessingException，并确保抛出的异常是 ShopException？

Answer 1

注意：这是部分答案，因为我还没有弄清楚所有情况。

如果您查看 JerseyInvocation, you will see the method invoke(Class responseType) 的源代码，这是在我们发出请求并传递我们希望将响应反序列化到的 class 参数时调用的方法。这是你在这里使用的，通过 Product.class

target.path("123!").request(APPLICATION_JSON).get(Product.class);

查看invoke()方法的源码，我们可以看到

return requestScope.runInScope(new Producer<T>() {
    @Override
    public T call() throws ProcessingException {
        try {
            return translate(runtime.invoke(requestForCall(requestContext)), requestScope, responseType);
        } catch (final ProcessingException ex) {
            if (ex.getCause() instanceof WebApplicationException) {
                throw (WebApplicationException) ex.getCause();
            }
            throw ex;
        }
    }
});

translate 方法将异常包装在 ProcessingException 中。如果您查看 catch 之后的几行，您应该会看到我们提供解决方法的机会。如果异常的原因是 WebApplicationException，那么将抛出该异常。因此，您的解决方法是使 ShopException 扩展 WebApplicationException.

现在我说这只是部分答案，因为当您只想从请求中返回 Response 时，这不起作用

Response res = target.path("123!").request(APPLICATION_JSON).get();

执行此操作时，将调用 invoke() (no arguments)。它与之前的 invoke() 方法做的事情不同。所以如果你能解决这个问题，那么你就有了完整的解决方案。

另一种解决方法是自己捕获 ProcessingException 并重新抛出原因。如果您正在制作 SDK，那么这一切都将在用户不知情的情况下完成。

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