Json 异常：Can not deserialize instance of xx out of START_ARRAY token

最新推荐文章于 2025-07-16 16:52:19 发布

转载最新推荐文章于 2025-07-16 16:52:19 发布 · 1.1w 阅读

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本文介绍了一个关于RESTful API中JSON数据解析的问题及解决方案。当服务器接收到客户端发送的JSON数组时，原本期望的是一个对象而非数组，导致了类型转换异常。通过调整服务器端的解析逻辑，将JSON数组转化为对象数组并取第一个元素，成功解决了该问题。

Server:

   01@RequestMapping(value = { "/hygiene/{phone}" }, method = {RequestMethod.POST },produces="application/json")

   02    @ResponseBody

   03    public PhoneResult hygiene(@PathVariable("phone")String phoneObject) {

   04        PhoneResult result = new PhoneResult();

   05        try {

   06            ObjectMapper mapper = new ObjectMapper();

   07            Phone phone = mapper.readValue(phoneObject, Phone.class);

   08            result.setRawPhoneNumber(phone.getPhoneNumber());

   09            result.setFormat("4+4+4");

   10            result.setCleanInternationalNumber("86 0513 23234442");

   11            result.setCleanNationalNumber("0513 23423423");

   12            result.setPreferredPresentation("513 234234234");

   13        }catch (Exception e) {

   14            e.printStackTrace();

   15            result.setCleanInternationalNumber("error");

   16        }

   17         

   18        return result;

   19    }

Client:

   1MultiValueMap<String,Object> dataMap2 = new LinkedMultiValueMap<String, Object>();

   2    Phone p = new Phone();

   3    p.setPhoneNumber("0513 23423423");

   4    dataMap2.add("phone", JsonUtil.javaToJson(p));

   5    HttpEntity<Object> entity2 = new HttpEntity<Object>(dataMap2); 

   6    PhoneResult result = this.restTemplate.postForObject("http://localhost:8080/restServer/helloworld/hygiene/{phone}.spring", entity2,  PhoneResult.class, dataMap2);

   1public static String javaToJson(Object o) throws Exception{

   2        StringWriter writer = new StringWriter();

   3        ObjectMapper mapper = new ObjectMapper();

   4        mapper.writeValue(writer, o);

   5        String json=writer.toString();

   6        return json;

   7    }

遇到的异常： server端转化json失败：

   1org.codehaus.jackson.map.JsonMappingException: Can not deserialize instance of com.pojo.Phone out of START_ARRAY token

   2 at [Source: java.io.StringReader@55afbf49; line: 1, column: 1]

   3    at org.codehaus.jackson.map.JsonMappingException.from(JsonMappingException.java:163)

   4    at org.codehaus.jackson.map.deser.StdDeserializationContext.mappingException(StdDeserializationContext.java:198)

   5    at org.codehaus.jackson.map.deser.BeanDeserializer.deserializeUsingCreator(BeanDeserializer.java:565)

   6    at org.codehaus.jackson.map.deser.BeanDeserializer.deserialize(BeanDeserializer.java:365)

   7    at org.codehaus.jackson.map.ObjectMapper._readMapAndClose(ObjectMapper.java:2391)

   8    at org.codehaus.jackson.map.ObjectMapper.readValue(ObjectMapper.java:1591)

   9    at com.acxiom.rest.controller.HelloWorldController.hygiene(HelloWorldController.java:52)

Debug了一下程序，发现传进来的json字符串是数组格式的：

[{"phoneNumber":"0513 XXXXX","phoneType":"1","countryCode":"1","geoOption":"1","defaultOption":"1","geoLat":"1","geoLong":"1"}]

果断修改了Server端代码：

   1ObjectMapper mapper = new ObjectMapper();

   2Phone phone = mapper.readValue(phoneObject, Phone[].class)[0];

问题解决。