Question

我有Spring MVC应用程序，它接收从Javascript前端发布的JSON。使用Jackson 2，自定义对象映射器仅将ACCEPT_SINGLE_VALUE_AS_ARRAY设置为true。以下是我的代码段。

启用MVC Java配置：

@Configuration
@EnableWebMvc
public class WebConfig extends WebMvcConfigurerAdapter {

    @Override
    public void configureMessageConverters(List<HttpMessageConverter<?>> converters) {
        converters.add(0, jackson2Converter());
    }

    @Primary
    @Bean
    public MappingJackson2HttpMessageConverter jackson2Converter() {
        MappingJackson2HttpMessageConverter converter = new MappingJackson2HttpMessageConverter();
        converter.setObjectMapper(objectMapper());
        return converter;
    }

    @Primary
    @Bean
    public ObjectMapper objectMapper() {
        ObjectMapper objectMapper = new ObjectMapper();
        objectMapper.configure(DeserializationFeature.ACCEPT_SINGLE_VALUE_AS_ARRAY, true);
        return objectMapper;
    }
}

Controller.java：

@RequestMapping(value = "home", method = RequestMethod.POST, consumes = "application/json")
@ResponseBody
public String submitForm(@RequestBody final Shipment shipment) { 
...
}

POJO：

  class Shipment implements Serializable { 

    private String dstState;
    private List<String> dstCities;
    // getters, setters and default constructor
    }

Ajax POST调用：

$.ajax({ url: ".../home", type: "POST", data: JSON.stringify(("#shipForm").serializeArray()), contentType: "application/json", dataType: 'json', ....

发布的JSON对象：mydata：{＆＃34; dstState＆＃34;：＆＃34; NV＆＃34; ，＆＃34; dstCities＆＃34;：＆＃34;拉斯维加斯＆＃34;}

收到POST后，出现错误：

Could not read JSON: Can not deserialize instance of java.util.ArrayList out of VALUE_STRING token
 at [Source: java.io.PushbackInputStream@44733b90; line: 1, column: 90] (through reference chain: com.*.Shipment["dstCities"]); nested exception is com.fasterxml.jackson.databind.JsonMappingException: Can not deserialize instance of java.util.ArrayList out of VALUE_STRING token

请指出我在这里失踪的任何事情

Answer 1

您输入的json数据格式不正确。

Shipment Json代表：

Shipment是Json对象
String dstState也是Json对象
List<String> dstCities是Json Array

正确的Shipment类的Json数据格式就像

 [{"dstState":"NV" , "dstCities": ["Las Vegas"]}]

或

[{"dstState":"NV" , "dstCities": ["Las Vegas", "Las Not Vegas"]}]

春天的Jackson Object Mapper无法正常工作

1 个答案: