Spring Jackson 没有从接口转换 class

Question

我正在将以下 JSON 发布到网络服务器：

{
    "driver": "POSTGRES",
    "server": "teste",
    "port": "666",
    "sid": "teste",
    "schema": "teste",
    "datasource": {
        "name": "Novo datasource",
        "description": "",
        "type": "DATABASE",
        "user": "",
        "password": ""
    }
}

到此映射：

@RequestMapping(
    method = RequestMethod.POST,
    consumes = MediaType.APPLICATION_JSON_VALUE,
    produces = MediaType.APPLICATION_JSON_VALUE)
public ResponseEntity<SomeInterface> save(SomeInterface object) {
    SomeInterface newObject = service.save(object);
    return new ResponseEntity<>(newObject, HttpStatus.CREATED);
}

我得到一个 400 状态代码，映射到 org.springframework.http.converter.HttpMessageNotReadableException，根本没有堆栈跟踪。

我有 4 个实现此 SomeInterface 的数据库实体，我想做的是在控制器中接收它们中的任何一个，并将其传递给服务上的策略。

为什么 Jackson 抛出异常而不只是转换 JSON？

---编辑---

我运行这是单元测试的结果，调试控制台中唯一显示的是断言错误异常，如下所示：

saveDatabaseDatasource(br.com.cds.connecta.presenter.DatasourceTest)  Time elapsed: 10.862 sec  <<< FAILURE!
java.lang.AssertionError: Content type not set
    at org.springframework.test.util.AssertionErrors.fail(AssertionErrors.java:39)
    at org.springframework.test.util.AssertionErrors.assertTrue(AssertionErrors.java:72)
    at org.springframework.test.web.servlet.result.ContentResultMatchers.match(ContentResultMatchers.java:75)
    at org.springframework.test.web.servlet.MockMvc.andExpect(MockMvc.java:148)
    at br.com.cds.connecta.presenter.DatasourceTest.saveDatabaseDatasource(DatasourceTest.java:26)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.lang.reflect.Method.invoke(Method.java:606)
    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.springframework.test.context.junit4.statements.RunBeforeTestMethodCallbacks.evaluate(RunBeforeTestMethodCallbacks.java:74)
    at org.springframework.test.context.junit4.statements.RunAfterTestMethodCallbacks.evaluate(RunAfterTestMethodCallbacks.java:83)
    at org.springframework.test.context.junit4.statements.SpringRepeat.evaluate(SpringRepeat.java:72)
    at org.springframework.test.context.junit4.SpringJUnit4ClassRunner.runChild(SpringJUnit4ClassRunner.java:231)
    at org.springframework.test.context.junit4.SpringJUnit4ClassRunner.runChild(SpringJUnit4ClassRunner.java:88)
    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[=14=]0(ParentRunner.java:58)
    at org.junit.runners.ParentRunner.evaluate(ParentRunner.java:268)
    at org.springframework.test.context.junit4.statements.RunBeforeTestClassCallbacks.evaluate(RunBeforeTestClassCallbacks.java:61)
    at org.springframework.test.context.junit4.statements.RunAfterTestClassCallbacks.evaluate(RunAfterTestClassCallbacks.java:71)
    at org.junit.runners.ParentRunner.run(ParentRunner.java:363)
    at org.springframework.test.context.junit4.SpringJUnit4ClassRunner.run(SpringJUnit4ClassRunner.java:174)
    at org.apache.maven.surefire.junit4.JUnit4Provider.execute(JUnit4Provider.java:252)
    at org.apache.maven.surefire.junit4.JUnit4Provider.executeTestSet(JUnit4Provider.java:141)
    at org.apache.maven.surefire.junit4.JUnit4Provider.invoke(JUnit4Provider.java:112)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.lang.reflect.Method.invoke(Method.java:606)
    at org.apache.maven.surefire.util.ReflectionUtils.invokeMethodWithArray(ReflectionUtils.java:189)
    at org.apache.maven.surefire.booter.ProviderFactory$ProviderProxy.invoke(ProviderFactory.java:165)
    at org.apache.maven.surefire.booter.ProviderFactory.invokeProvider(ProviderFactory.java:85)
    at org.apache.maven.surefire.booter.ForkedBooter.runSuitesInProcess(ForkedBooter.java:115)
    at org.apache.maven.surefire.booter.ForkedBooter.main(ForkedBooter.java:75)

Answer 1

除非您使用 Jackson's polymorphic deserialization features，否则 Jackson 绝对无法猜测您的四个（或更多）SomeInterface 实现中的哪一个用作目标反序列化 class。因此，Jackson 无法解析您的 JSON 并向 Spring.

抛出异常

如果您将日志级别设置为 DEBUG，您会看到更具体的原因。

Spring Jackson 没有从接口转换 class

Spring Jackson not converting class from interface

java

spring

json

spring-mvc

jackson