java - Spring Boot Jackson 映射不起作用

Question

我正在使用 fastxml jackson 进行 json 序列化。我已将日期序列化器编写为

public class DateObjectSerializer extends JsonSerializer<Date> {
    public static final String DATE_FORMAT = "dd.MM.yyyy";

    @Override
    public void serialize(Date date, JsonGenerator jgen, SerializerProvider provider) throws IOException, JsonProcessingException {
        System.out.println("From DateObjectSerializer");
        SimpleDateFormat dateFormat = new SimpleDateFormat(DATE_FORMAT);
        String formattedDate = dateFormat.format(date);
        jgen.writeString(formattedDate);
    }
}

但它没有被调用。然而其他 Jackson 序列化器工作正常。

所以我在application.yaml中添加了以下配置

spring:
  jackson:
    serialization-inclusion: non_null
    date-format: dd.MM.yyyy

但是没用。

所以我在 SpringBootConfiguration 类中添加了这段代码。

@Override
public void configureMessageConverters(List<HttpMessageConverter<?>> converters) {
    final MappingJackson2HttpMessageConverter converter = new MappingJackson2HttpMessageConverter();
    final ObjectMapper objectMapper = new ObjectMapper();
    SimpleDateFormat dateFormat = new SimpleDateFormat(DATE_FORMAT);
    objectMapper.configure(SerializationFeature.WRITE_DATES_AS_TIMESTAMPS, false).setDateFormat(dateFormat);
    converter.setObjectMapper(objectMapper);
    converters.add(converter);
    super.configureMessageConverters(converters);
}

现在日期已正确序列化。但现在有效的 JSON 等效字符串不会转换为 JSON，如上所述 here .

@RestController
public class SampleController {

    @RequestMapping(value = "/jsonInfo", method = RequestMethod.GET, produces = APPLICATION_JSON_VALUE)
    public String jsonInfo() {
        String string = "{\"name\": \"foo\"}"
                return string;
    }
}

Answer 1

试试这个

import com.fasterxml.jackson.databind.ObjectMapper;

:

@Autowired
private ObjectMapper objectMapper;

@RestController
public class SampleController {

    @RequestMapping(value = "/jsonInfo", method = RequestMethod.GET, produces = APPLICATION_JSON_VALUE)
    public JsonNode jsonInfo()  throws JsonProcessingException, IOException {
        String string = "{\"name\": \"foo\"}"
                return objectMapper.readTree(string);
    }
}