I'm writing the integration for a couple API service calls; one of those services was simple. A quick Item item = restTemplate.getForObject(url, Item.class)
where Item
is just a POJO and everything was mapped right into that object.
The other service is problematic. The call is almost the same: Attribute[] attribute = restTemplate.getForObject(url, Attribute[].class)
with the difference being that the JSON response has a top level array. Here's the Attribute
class:
@Data public class ItemAttributes { private Long id; private Attribute[] attributes; @Data private static class Attribute { private String name; //a bunch of other fields } }
All my digging says the above should work. Instead I get this:
org.springframework.http.converter.HttpMessageNotReadableException: Could not read document: javax.xml.stream.XMLStreamException: ParseError at [row,col]:[1,1] Message: Content is not allowed in prolog.; nested exception is java.io.IOException: javax.xml.stream.XMLStreamException: ParseError at [row,col]:[1,1] Message: Content is not allowed in prolog. at org.springframework.http.converter.json.AbstractJackson2HttpMessageConverter.readJavaType(AbstractJackson2HttpMessageConverter.java:224) at org.springframework.http.converter.json.AbstractJackson2HttpMessageConverter.read(AbstractJackson2HttpMessageConverter.java:208) at org.springframework.web.client.HttpMessageConverterExtractor.extractData(HttpMessageConverterExtractor.java:95) at org.springframework.web.client.RestTemplate.doExecute(RestTemplate.java:599) at org.springframework.web.client.RestTemplate.execute(RestTemplate.java:557) at org.springframework.web.client.RestTemplate.getForObject(RestTemplate.java:264) at com.homedepot.order.gateway.resource.ItemAttributeServiceResource.getItemAttributes(ItemAttributeServiceResource.java:37) at com.homedepot.order.gateway.resource.ItemAttributeServiceResource.getItemAttributes(ItemAttributeServiceResource.java:32) at com.homedepot.order.gateway.resource.ItemAttributeServiceResourceTest.testStuffOneItem(ItemAttributeServiceResourceTest.java:62) 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:497) at org.testng.internal.MethodInvocationHelper.invokeMethod(MethodInvocationHelper.java:85) at org.testng.internal.Invoker.invokeMethod(Invoker.java:639) at org.testng.internal.Invoker.invokeTestMethod(Invoker.java:821) at org.testng.internal.Invoker.invokeTestMethods(Invoker.java:1131) at org.testng.internal.TestMethodWorker.invokeTestMethods(TestMethodWorker.java:124) at org.testng.internal.TestMethodWorker.run(TestMethodWorker.java:108) at org.testng.TestRunner.privateRun(TestRunner.java:773) at org.testng.TestRunner.run(TestRunner.java:623) at org.testng.SuiteRunner.runTest(SuiteRunner.java:357) at org.testng.SuiteRunner.runSequentially(SuiteRunner.java:352) at org.testng.SuiteRunner.privateRun(SuiteRunner.java:310) at org.testng.SuiteRunner.run(SuiteRunner.java:259) at org.testng.SuiteRunnerWorker.runSuite(SuiteRunnerWorker.java:52) at org.testng.SuiteRunnerWorker.run(SuiteRunnerWorker.java:86) at org.testng.TestNG.runSuitesSequentially(TestNG.java:1185) at org.testng.TestNG.runSuitesLocally(TestNG.java:1110) at org.testng.TestNG.run(TestNG.java:1018) at org.testng.IDEARemoteTestNG.run(IDEARemoteTestNG.java:72) at org.testng.RemoteTestNGStarter.main(RemoteTestNGStarter.java:122) 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:497) at com.intellij.rt.execution.application.AppMain.main(AppMain.java:144) Caused by: java.io.IOException: javax.xml.stream.XMLStreamException: ParseError at [row,col]:[1,1] Message: Content is not allowed in prolog. at com.fasterxml.jackson.dataformat.xml.util.StaxUtil.throwXmlAsIOException(StaxUtil.java:24) at com.fasterxml.jackson.dataformat.xml.XmlFactory._createParser(XmlFactory.java:539) at com.fasterxml.jackson.dataformat.xml.XmlFactory._createParser(XmlFactory.java:29) at com.fasterxml.jackson.core.JsonFactory.createParser(JsonFactory.java:802) at com.fasterxml.jackson.databind.ObjectMapper.readValue(ObjectMapper.java:2810) at org.springframework.http.converter.json.AbstractJackson2HttpMessageConverter.readJavaType(AbstractJackson2HttpMessageConverter.java:221) ... 36 more Caused by: javax.xml.stream.XMLStreamException: ParseError at [row,col]:[1,1] Message: Content is not allowed in prolog. at com.sun.org.apache.xerces.internal.impl.XMLStreamReaderImpl.next(XMLStreamReaderImpl.java:596) at com.fasterxml.jackson.dataformat.xml.XmlFactory._initializeXmlReader(XmlFactory.java:648) at com.fasterxml.jackson.dataformat.xml.XmlFactory._createParser(XmlFactory.java:537) ... 40 more
And additional digging has just lead me in circles. First, that's an XML specific Exception for what I've double-checked is actually a JSON response. Second, even if it was XML, RestTemplate should automatically register the correct HttpMessageConverter and mapper. (Right? That's what the documentation says.)
If I use ResponseEntity<String> response = restTemplate.getForEntity(url, String.class)
and print response.getBody().toString()
I get something that looks like this:
[{"id":12345678,"attributes":[{"f1":"value1","f2":"value2","f3":"value3"}, {"f1":"value4","f2":"value5","f3":"value6"}]}]
I know I could run with that, create an ObjectMapper
and a parser and grab what I want, but that doesn't address the bigger question of why the other approach isn't working, and why it's throwing that exception.
Any help will be greatly appreciated.
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