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The problem of deserializing from XML to POJO using Jackson: there is no constructor of string constructors / factory to deserialize from String value

I have an XML document that I need to convert (deserialize) to Java POJO. I cannot change the structure of an XML document. I am using Java 8 and the Jackson framework for matching. Gradle :

dependencies { compile('com.fasterxml.jackson.dataformat:jackson-dataformat-xml') compile('org.springframework.boot:spring-boot-starter-freemarker') compile('org.springframework.boot:spring-boot-starter-web') providedRuntime('org.springframework.boot:spring-boot-starter-tomcat') testCompile('org.springframework.boot:spring-boot-starter-test') }

Wrapper XML Doc:

 @JacksonXmlRootElement(localName = "rates_response") public class RatesResponse implements Serializable{ private static final long serialVersionUID = 3254688495454519L; @JacksonXmlProperty(isAttribute = true) private String b_number = ""; @JacksonXmlProperty(isAttribute = true) private String l_premium = ""; @JacksonXmlProperty(isAttribute = true) private String currency = ""; @XmlElement(required = false) @JacksonXmlProperty private String c_b_relationship = null; @JacksonXmlProperty(isAttribute = true) private String n_of_p_loans = null; /* * Key: status_code * Key: status_explanation */ @JacksonXmlElementWrapper private Map<String, String> message_status = null; // @XmlElement @JacksonXmlElementWrapper(useWrapping = false) private List<RateDetails> rate_details = null; public RatesResponse(){} //GETTERS/SETTERS Child document (`List<RateDetails> rate_details = null;`): @JacksonXmlRootElement(localName = "rate_details") public class RateDetails implements Serializable { private static final long serialVersionUID = 324564684815158619L; @JacksonXmlProperty private String r_reference = null; @JacksonXmlProperty private String n_of_p_days = null; @JacksonXmlProperty private String n_of_instalments = null; @JacksonXmlProperty private String n_rate = null; @JacksonXmlProperty private String p_p_available = null; @XmlElement(required = false) @JacksonXmlProperty private String i_overrider = null;//not always appears in doc @JacksonXmlProperty private String a_fee = null; @JacksonXmlProperty private String m_fee = null; @JacksonXmlProperty private String t_fees = null; @JacksonXmlProperty private String t_c_for_credit = null; @JacksonXmlProperty private String d_amount = null; @JacksonXmlProperty private String apr = null; public RateDetails(){} //GETTERS/SETTERS

XML document for analysis:

 <?xml version="1.0"?> <!DOCTYPE rates_response SYSTEM "p_f_interface.dtd"> <rates_response b_number="KK5000000000" l_premium="5000.00" currency="GBP" > <message_status> <status_code>1000</status_code> <status_explanation>Success</status_explanation> </message_status> <c_b_relationship n_of_p_loans="0"/> <rate_details> <r_reference>AS28</r_reference> <n_of_p_days>28</n_of_p_days> <n_of_instalments>12</n_of_instalments> <n_rate>7.00</n_rate> <p_p_available>NO</p_p_available> <i_overrider>3.65</i_overrider> <a_fee>0.00</a_fee> <m_fee>0.00</m_fee> <t_fees>0.00</t_fees> <t_c_for_credit>350.00</t_c_for_credit> <d_amount>0.00</d_amount> <apr>16.05</apr> </rate_details> </rates_response>

A method that parses a document:

 private RatesResponse readRatesDoc() { RatesResponse xmlContainer = null; ObjectMapper xmlMapper = new XmlMapper(); try { xmlContainer = xmlMapper.readValue(contrUtil.readXmlFile("Rates_Response.xml"), RatesResponse.class); } catch (IOException e) { log.log(Level.SEVERE, "An Exception on parsing XML document", e); } return xmlContainer; }

An exception:

 com.fasterxml.jackson.databind.JsonMappingException: Can not construct instance of premium.finance.beanResponse.rates.RateDetails: no String-argument constructor/factory method to deserialize from String value ('16.05') at [Source: java.io.StringReader@7bd22d0b ; line: 1, column: 945] (through reference chain: premium.finance.beanResponse.rates.RatesResponse["rate_details"]->java.util.ArrayList[1]) at com.fasterxml.jackson.databind.JsonMappingException.from(JsonMappingException.java:261) ~[jackson-databind-2.8.3.jar:2.8.3] at com.fasterxml.jackson.databind.DeserializationContext.instantiationException(DeserializationContext.java:1456) ~[jackson-databind-2.8.3.jar:2.8.3] at com.fasterxml.jackson.databind.DeserializationContext.handleMissingInstantiator(DeserializationContext.java:1012) ~[jackson-databind-2.8.3.jar:2.8.3] at com.fasterxml.jackson.databind.deser.ValueInstantiator._createFromStringFallbacks(ValueInstantiator.java:366) ~[jackson-databind-2.8.3.jar:2.8.3] at com.fasterxml.jackson.databind.deser.std.StdValueInstantiator.createFromString(StdValueInstantiator.java:307) ~[jackson-databind-2.8.3.jar:2.8.3] at com.fasterxml.jackson.databind.deser.BeanDeserializerBase.deserializeFromString(BeanDeserializerBase.java:1278) ~[jackson-databind-2.8.3.jar:2.8.3] at com.fasterxml.jackson.databind.deser.BeanDeserializer._deserializeOther(BeanDeserializer.java:159) ~[jackson-databind-2.8.3.jar:2.8.3] at com.fasterxml.jackson.databind.deser.BeanDeserializer.deserialize(BeanDeserializer.java:150) ~[jackson-databind-2.8.3.jar:2.8.3] at com.fasterxml.jackson.databind.deser.std.CollectionDeserializer.deserialize(CollectionDeserializer.java:277) ~[jackson-databind-2.8.3.jar:2.8.3] at com.fasterxml.jackson.databind.deser.std.CollectionDeserializer.deserialize(CollectionDeserializer.java:249) ~[jackson-databind-2.8.3.jar:2.8.3] at com.fasterxml.jackson.databind.deser.std.CollectionDeserializer.deserialize(CollectionDeserializer.java:26) ~[jackson-databind-2.8.3.jar:2.8.3] at com.fasterxml.jackson.databind.deser.SettableBeanProperty.deserialize(SettableBeanProperty.java:499) ~[jackson-databind-2.8.3.jar:2.8.3] at com.fasterxml.jackson.databind.deser.impl.MethodProperty.deserializeAndSet(MethodProperty.java:101) ~[jackson-databind-2.8.3.jar:2.8.3] at com.fasterxml.jackson.databind.deser.BeanDeserializer.vanillaDeserialize(BeanDeserializer.java:276) ~[jackson-databind-2.8.3.jar:2.8.3] at com.fasterxml.jackson.databind.deser.BeanDeserializer.deserialize(BeanDeserializer.java:140) ~[jackson-databind-2.8.3.jar:2.8.3] at com.fasterxml.jackson.dataformat.xml.deser.WrapperHandlingDeserializer.deserialize(WrapperHandlingDeserializer.java:120) ~[jackson-dataformat-xml-2.8.3.jar:2.8.3] at com.fasterxml.jackson.databind.ObjectMapper._readMapAndClose(ObjectMapper.java:3789) ~[jackson-databind-2.8.3.jar:2.8.3] at com.fasterxml.jackson.databind.ObjectMapper.readValue(ObjectMapper.java:2833) ~[jackson-databind-2.8.3.jar:2.8.3] at premium.finance.controller.IndexController.readRatesDoc(IndexController.java:190) [main/:na] at premium.finance.controller.IndexController.requestIndex(IndexController.java:69) [main/:na] at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) ~[na:1.8.0_91] at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62) ~[na:1.8.0_91] at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) ~[na:1.8.0_91] at java.lang.reflect.Method.invoke(Method.java:498) ~[na:1.8.0_91] at org.springframework.web.method.support.InvocableHandlerMethod.doInvoke(InvocableHandlerMethod.java:221) [spring-web-4.3.3.RELEASE.jar:4.3.3.RELEASE] at org.springframework.web.method.support.InvocableHandlerMethod.invokeForRequest(InvocableHandlerMethod.java:136) [spring-web-4.3.3.RELEASE.jar:4.3.3.RELEASE] at org.springframework.web.servlet.mvc.method.annotation.ServletInvocableHandlerMethod.invokeAndHandle(ServletInvocableHandlerMethod.java:114) [spring-webmvc-4.3.3.RELEASE.jar:4.3.3.RELEASE] at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.invokeHandlerMethod(RequestMappingHandlerAdapter.java:827) [spring-webmvc-4.3.3.RELEASE.jar:4.3.3.RELEASE] at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.handleInternal(RequestMappingHandlerAdapter.java:738) [spring-webmvc-4.3.3.RELEASE.jar:4.3.3.RELEASE] at org.springframework.web.servlet.mvc.method.AbstractHandlerMethodAdapter.handle(AbstractHandlerMethodAdapter.java:85) [spring-webmvc-4.3.3.RELEASE.jar:4.3.3.RELEASE] at org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:963) [spring-webmvc-4.3.3.RELEASE.jar:4.3.3.RELEASE] at org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:897) [spring-webmvc-4.3.3.RELEASE.jar:4.3.3.RELEASE] at org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:970) [spring-webmvc-4.3.3.RELEASE.jar:4.3.3.RELEASE] at org.springframework.web.servlet.FrameworkServlet.doGet(FrameworkServlet.java:861) [spring-webmvc-4.3.3.RELEASE.jar:4.3.3.RELEASE] at javax.servlet.http.HttpServlet.service(HttpServlet.java:622) [tomcat-embed-core-8.5.5.jar:8.5.5] at org.springframework.web.servlet.FrameworkServlet.service(FrameworkServlet.java:846) [spring-webmvc-4.3.3.RELEASE.jar:4.3.3.RELEASE] at javax.servlet.http.HttpServlet.service(HttpServlet.java:729) [tomcat-embed-core-8.5.5.jar:8.5.5] at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:230) [tomcat-embed-core-8.5.5.jar:8.5.5] at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:165) [tomcat-embed-core-8.5.5.jar:8.5.5] at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52) [tomcat-embed-websocket-8.5.5.jar:8.5.5] at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:192) [tomcat-embed-core-8.5.5.jar:8.5.5] at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:165) [tomcat-embed-core-8.5.5.jar:8.5.5] at org.springframework.web.filter.RequestContextFilter.doFilterInternal(RequestContextFilter.java:99) [spring-web-4.3.3.RELEASE.jar:4.3.3.RELEASE] at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107) [spring-web-4.3.3.RELEASE.jar:4.3.3.RELEASE] at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:192) [tomcat-embed-core-8.5.5.jar:8.5.5] at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:165) [tomcat-embed-core-8.5.5.jar:8.5.5] at org.springframework.web.filter.HttpPutFormContentFilter.doFilterInternal(HttpPutFormContentFilter.java:89) [spring-web-4.3.3.RELEASE.jar:4.3.3.RELEASE] at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107) [spring-web-4.3.3.RELEASE.jar:4.3.3.RELEASE] at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:192) [tomcat-embed-core-8.5.5.jar:8.5.5] at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:165) [tomcat-embed-core-8.5.5.jar:8.5.5] at org.springframework.web.filter.HiddenHttpMethodFilter.doFilterInternal(HiddenHttpMethodFilter.java:77) [spring-web-4.3.3.RELEASE.jar:4.3.3.RELEASE] at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107) [spring-web-4.3.3.RELEASE.jar:4.3.3.RELEASE] at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:192) [tomcat-embed-core-8.5.5.jar:8.5.5] at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:165) [tomcat-embed-core-8.5.5.jar:8.5.5] at org.springframework.web.filter.CharacterEncodingFilter.doFilterInternal(CharacterEncodingFilter.java:197) [spring-web-4.3.3.RELEASE.jar:4.3.3.RELEASE] at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107) [spring-web-4.3.3.RELEASE.jar:4.3.3.RELEASE] at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:192) [tomcat-embed-core-8.5.5.jar:8.5.5] at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:165) [tomcat-embed-core-8.5.5.jar:8.5.5] at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:198) [tomcat-embed-core-8.5.5.jar:8.5.5] at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:108) [tomcat-embed-core-8.5.5.jar:8.5.5] at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:472) [tomcat-embed-core-8.5.5.jar:8.5.5] at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:140) [tomcat-embed-core-8.5.5.jar:8.5.5] at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:79) [tomcat-embed-core-8.5.5.jar:8.5.5] at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:87) [tomcat-embed-core-8.5.5.jar:8.5.5] at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:349) [tomcat-embed-core-8.5.5.jar:8.5.5] at org.apache.coyote.http11.Http11Processor.service(Http11Processor.java:784) [tomcat-embed-core-8.5.5.jar:8.5.5] at org.apache.coyote.AbstractProcessorLight.process(AbstractProcessorLight.java:66) [tomcat-embed-core-8.5.5.jar:8.5.5] at org.apache.coyote.AbstractProtocol$ConnectionHandler.process(AbstractProtocol.java:802) [tomcat-embed-core-8.5.5.jar:8.5.5] at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:1410) [tomcat-embed-core-8.5.5.jar:8.5.5] at org.apache.tomcat.util.net.SocketProcessorBase.run(SocketProcessorBase.java:49) [tomcat-embed-core-8.5.5.jar:8.5.5] at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142) [na:1.8.0_91] at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617) [na:1.8.0_91] at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61) [tomcat-embed-core-8.5.5.jar:8.5.5] at java.lang.Thread.run(Thread.java:745) [na:1.8.0_91]

The top line says:

 no String-argument constructor/factory method to deserialize from String value ('16.05')

The value it refers to is due to this tag:

 <apr>16.05</apr>

If I move (move) the tag, <apr>16.05</apr> , the parser works and no exception is thrown. If I replace the tag with another tag, the same exception will still occur; it affects only the last tag of the <rate_details> tag of the tag .

What could be the problem?

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2 answers

It seems to be a mistake ; filed it here: https://github.com/FasterXML/jackson-dataformat-xml/issues/219

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You can try adding the @JsonCreator annotation to your default constructor, which should help. Do you have another constructor for this class in your code?

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Source: https://habr.com/ru/post/1013346/

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