春傑克遜不是從接口

Question

轉換類我張貼以下JSON到Web服務器：

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

對此映射：

@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); 
} 

而且我得到一個400個狀態碼，映射到根本沒有堆棧跟蹤的org.springframework.http.converter.HttpMessageNotReadableException。

我有4個DB實體實現這個SomeInterface，我想要做的就是在控制器中接收它們中的任何一個，並將它傳遞給服務上的策略。

爲什麼傑克遜拋出該異常而不是僅僅轉換JSON？

---編輯---

我是從一個單元測試運行這一點，並在調試控制檯中顯示出來的僅僅是斷言錯誤異常如下：

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$1.match(ContentResultMatchers.java:75) 
    at org.springframework.test.web.servlet.MockMvc$1.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$1.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$3.run(ParentRunner.java:290) 
    at org.junit.runners.ParentRunner$1.schedule(ParentRunner.java:71) 
    at org.junit.runners.ParentRunner.runChildren(ParentRunner.java:288) 
    at org.junit.runners.ParentRunner.access$000(ParentRunner.java:58) 
    at org.junit.runners.ParentRunner$2.evaluate(ParentRunner.java:268) 
    at org.springframework.test.context.junit4.statements.RunBeforeTestClassCallbacks.evaluate(RunBeforeTestClassCallbacks.java:61) 
    at org.springframework.test.context.junit4.statements.RunAfterTestClassCallbacks.evaluate(RunAfterTestClassCallbacks.java:71) 
    at org.junit.runners.ParentRunner.run(ParentRunner.java:363) 
    at org.springframework.test.context.junit4.SpringJUnit4ClassRunner.run(SpringJUnit4ClassRunner.java:174) 
    at org.apache.maven.surefire.junit4.JUnit4Provider.execute(JUnit4Provider.java:252) 
    at org.apache.maven.surefire.junit4.JUnit4Provider.executeTestSet(JUnit4Provider.java:141) 
    at org.apache.maven.surefire.junit4.JUnit4Provider.invoke(JUnit4Provider.java:112) 
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) 
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57) 
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) 
    at java.lang.reflect.Method.invoke(Method.java:606) 
    at org.apache.maven.surefire.util.ReflectionUtils.invokeMethodWithArray(ReflectionUtils.java:189) 
    at org.apache.maven.surefire.booter.ProviderFactory$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，否則傑克遜絕對沒有辦法猜測您的四個（或更多）SomeInterface實現中的哪一個用作目標反序列化類。因此，傑克遜未能解析您的JSON並引發Spring的異常。

如果將日誌級別設置爲DEBUG，則會看到更具體的原因。