Question

当向服务器发送JSON请求时，我经常会收到此消息：

客户端发送的请求在语法上是不正确的（）。

通常它是传递的错误属性，控制器没有预料到，因为JSON映射到的对象不包含它。

查找参数是不必要的耗时 - 是否有办法获取更多信息，甚至可能是异常的堆栈跟踪？我尝试在调试模式下运行，我使用Jackson作为我的JSON（de）序列化器。

Answer 1

要获取更多信息/堆栈跟踪，请启用log4j.properties

中spring web的调试日志记录

log4j.logger.org.springframework.web =调试

Answer 2

如果您消费的数据来自外部API，并且您希望保护控制器免受不需要的元素/属性的影响您可以在POJO类

上使用以下注释

@JsonIgnoreProperties(ignoreUnknown = true)

或者您可以全局设置

//jackson 2.0
jsonObjectMapper.configure(DeserializationFeature.FAIL_ON_UNKNOWN_PROPERTIES, false);

Answer 3

旧案例，我现在无关紧要，但对于有类似问题的其他人，我会添加此条目。

检查您是否有双引号，而不是单引号。也试着逃避它们。

我将应用 curl 用于我的测试json请求。

我的JSON就像这样

{ 'name' : 'somedata', 'town':'some town' }

它在我眼中爆炸了。

“客户端发送的请求在语法上不正确”是一般错误。所以我把它从单引号改为双引号，没有去。然后我尝试在单引号前面反斜杠，仍然没有去。然后将它改为双引号和presto前面的反斜杠！

curl -i -H "Accept: application/json" -H "Content-Type: application/json" \ 
http://localhost:8077/dra/dump.json \ 
-X PUT -d "{\"name\" : \"My Name\", \"town\":\"My Town\"}"

Answer 4

我遇到了同样的错误，因为几天后，最终启用了@Farm提到的调试日志记录，并且能够看到此问题的原因。我有一个Person对象在json中从jsp发布到spring控制器，如下所示： -

@RequestMapping(value = "/get", method = RequestMethod.POST)
public @ResponseBody
Person getPerson(@RequestBody Person person) {
    // System.out.println("inside get::::::::");
    System.out.println("city:=" + person.getResidenceAddress().getCity()+" "
            + "name:= " + person.getFullName().getFirstName());
    // Person prsn = personService.getPerson(person);

    /*
     * Person prsn = new Person(); prsn.setId(1); ResponseDecorator rd = new
     * ResponseDecorator(prsn, true);
     */return person;
}
// Person Object
class Person{
private Name fullName;
private Address residenceAddress;
private Address mailingAddress;
private Gender gender;
private MaritalStatus maritalStatus;
private Integer creditRating;

}

 //Address Object
public class Address {
private String streetNo;
private String streetName;
private String suburb;
private String city;
private String state;
private String country;
private Integer pinCode;
private AddressType addressType;
}


json post from jsp:-
//create JSON 
var json = {
"id": id,
        "fullName":{"firstName":firstName,"middleName":middleName,"surName":     surName},
 "residenceAddress":{ "streetNo": streetNo,
                      "streetName": streetName,
                      "suburb": suburb,
                      "city": city,
                      "state": state,   
                      "country": country,
                      "pinCode": pincode
                      }
        };

 var dataString = JSON.stringify(json);
//alert(dataString);


$.ajax({
    headers: {
        Accept : "text/plain; charset=utf-8, application/json"},
    url: "/myservice/get", 
    type: 'POST', 
    dataType: 'json', 
    //data : "{     }",
    data: dataString, 
    contentType: 'application/json',
    mimeType: 'application/json',
    success: function(data) { 
        alert(data);
    },
    error:function(data,status,er) { 
        alert("error: "+data+" status: "+status+" er:"+er);
    }
});

提交错误是400 Bad请求，并且没有其他线索可以解释为什么失败。在服务器上启用调试模式后，我可以看到以下错误堆栈跟踪： -

**00:53:42,294 DEBUG RequestResponseBodyMethodProcessor:117 - Reading [com.foo.assignment.model.Person] as "application/json" using [org.springframework.http.converter.json.MappingJacksonHttpMessageConverter@1813fb]
00:53:42,310 DEBUG ServletInvocableHandlerMethod:159 - Error resolving argument [0] [type=com.foo.assignment.model.Person]
HandlerMethod details: 
Controller [com.foo.assignment.controller.PersonController]
Method [public com.foo.assignment.model.Person com.foo.assignment.controller.PersonController.getPerson(com.foo.assignment.model.Person)]
org.springframework.http.converter.HttpMessageNotReadableException: Could not read JSON: No suitable constructor found for type [simple type, class com.foo.assignment.model.Address]: can not instantiate from JSON object (need to add/enable type information?)
 at [Source: org.apache.catalina.connector.CoyoteInputStream@f264df; line: 1, column: 98] (through reference chain: com.foo.assignment.model.Person["residenceAddress"]); nested exception is org.codehaus.jackson.map.JsonMappingException: No suitable constructor found for type [simple type, class com.foo.assignment.model.Address]: can not instantiate from JSON object (need to add/enable type information?)
 at [Source: org.apache.catalina.connector.CoyoteInputStream@f264df; line: 1, column: 98] (through reference chain: com.foo.assignment.model.Person["residenceAddress"])
    at org.springframework.http.converter.json.MappingJacksonHttpMessageConverter.readInternal(MappingJacksonHttpMessageConverter.java:127)
    at org.springframework.http.converter.AbstractHttpMessageConverter.read(AbstractHttpMessageConverter.java:153)
    at org.springframework.web.servlet.mvc.method.annotation.AbstractMessageConverterMethodArgumentResolver.readWithMessageConverters(AbstractMessageConverterMethodArgumentResolver.java:120)
    at org.springframework.web.servlet.mvc.method.annotation.AbstractMessageConverterMethodArgumentResolver.readWithMessageConverters(AbstractMessageConverterMethodArgumentResolver.java:91)
    at org.springframework.web.servlet.mvc.method.annotation.RequestResponseBodyMethodProcessor.resolveArgument(RequestResponseBodyMethodProcessor.java:71)
    at org.springframework.web.method.support.HandlerMethodArgumentResolverComposite.resolveArgument(HandlerMethodArgumentResolverComposite.java:74)
    at org.springframework.web.method.support.InvocableHandlerMethod.getMethodArgumentValues(InvocableHandlerMethod.java:155)
    at org.springframework.web.method.support.InvocableHandlerMethod.invokeForRequest(InvocableHandlerMethod.java:117)
    at org.springframework.web.servlet.mvc.method.annotation.ServletInvocableHandlerMethod.invokeAndHandle(ServletInvocableHandlerMethod.java:96)
    at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.invokeHandlerMethod(RequestMappingHandlerAdapter.java:617)
    at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.handleInternal(RequestMappingHandlerAdapter.java:578)
    at org.springframework.web.servlet.mvc.method.AbstractHandlerMethodAdapter.handle(AbstractHandlerMethodAdapter.java:80)
    at org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:900)
    at org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:827)
    at org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:882)
    at org.springframework.web.servlet.FrameworkServlet.doPost(FrameworkServlet.java:789)
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:650)
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:731)
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:303)
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:208)
    at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52)
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:241)
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:208)
    at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:220)
    at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:122)
    at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:505)
    at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:170)
    at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:103)
    at org.apache.catalina.valves.AccessLogValve.invoke(AccessLogValve.java:957)
    at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:116)
    at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:423)
    at org.apache.coyote.http11.AbstractHttp11Processor.process(AbstractHttp11Processor.java:1079)
    at org.apache.coyote.AbstractProtocol$AbstractConnectionHandler.process(AbstractProtocol.java:620)
    at org.apache.tomcat.util.net.JIoEndpoint$SocketProcessor.run(JIoEndpoint.java:316)
    at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1110)
    at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:603)
    at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61)
    at java.lang.Thread.run(Thread.java:722)
Caused by: org.codehaus.jackson.map.JsonMappingException: No suitable constructor found for type [simple type, class com.foo.assignment.model.Address]: can not instantiate from JSON object (need to add/enable type information?)
 at [Source: org.apache.catalina.connector.CoyoteInputStream@f264df; line: 1, column: 98] (through reference chain: com.foo.assignment.model.Person["residenceAddress"])
    at org.codehaus.jackson.map.JsonMappingException.from(JsonMappingException.java:163)
    at org.codehaus.jackson.map.deser.BeanDeserializer.deserializeFromObjectUsingNonDefault(BeanDeserializer.java:746)
    at org.codehaus.jackson.map.deser.BeanDeserializer.deserializeFromObject(BeanDeserializer.java:683)
    at org.codehaus.jackson.map.deser.BeanDeserializer.deserialize(BeanDeserializer.java:580)
    at org.codehaus.jackson.map.deser.SettableBeanProperty.deserialize(SettableBeanProperty.java:299)
    at org.codehaus.jackson.map.deser.SettableBeanProperty$MethodProperty.deserializeAndSet(SettableBeanProperty.java:414)
    at org.codehaus.jackson.map.deser.BeanDeserializer.deserializeFromObject(BeanDeserializer.java:697)
    at org.codehaus.jackson.map.deser.BeanDeserializer.deserialize(BeanDeserializer.java:580)
    at org.codehaus.jackson.map.ObjectMapper._readMapAndClose(ObjectMapper.java:2732)
    at org.codehaus.jackson.map.ObjectMapper.readValue(ObjectMapper.java:1923)
    at org.springframework.http.converter.json.MappingJacksonHttpMessageConverter.readInternal(MappingJacksonHttpMessageConverter.java:124)
    ... 37 more
00:53:42,310 DEBUG ExceptionHandlerException**

在Address对象中添加默认构造函数解决了错误。使用Google附加组件Postman（插件https://chrome.google.com/webstore/detail/postman/fhbjgbiflinjbdggehcddcbncdddomop?hl=en）确实可以非常快速地测试我的更改。

Answer 5

问题在于您的POJO，将服务器日志级别保持在调试级别并检查错误。这主要与某些领域和领域类型不匹配有关。

Answer 6

使用嵌套类时也会发生此错误 e.g。

class One {
    some code..

    public class NestedOne {
        private attr;

        public NestedOne() {
            // default constructor
        }
    }
}

然后拥有 @RequestMapping(value = "/something") public String someControllerMethod(@RequestBody One.NestedOne nested) { ... }

jackson然后不识别NestedOne（）作为默认构造函数并搜索One.NestedOne（）构造函数。

Spring MVC：客户端发送的请求在语法上是不正确的

6 个答案: