fastjson 2 的ObjectReader 怎么实现？

请问能不能提供一个 实现 ObjectReader 的例子，FastJson2 网上教程太难找了，全是 FastJson1 的教程，然后 com.alibaba.fastjson2.writer 包下的类是不是现在还不能使用，如 ObjectWriterImplLocalDateTime.class

我想解决的问题是，后端接收 LocalDateTime 属性，前端传值：“2022-05-26”，正常，但是传值：“2022-05-26 16:42:11” 就会报错，下面是我写的 配置类 , 学习的路上，能不能提供一个解决方案，琢磨一整天了。

import com.alibaba.fastjson2.JSON; import com.alibaba.fastjson2.JSONException; import com.alibaba.fastjson2.JSONReader; import com.alibaba.fastjson2.JSONWriter; import com.alibaba.fastjson2.reader.ObjectReader; import com.alibaba.fastjson2.support.config.FastJsonConfig; import com.alibaba.fastjson2.support.spring.http.converter.FastJsonHttpMessageConverter; import com.alibaba.fastjson2.writer.ObjectWriter; import org.springframework.context.annotation.Configuration; import org.springframework.http.MediaType; import org.springframework.http.converter.HttpMessageConverter; import org.springframework.web.servlet.config.annotation.EnableWebMvc; import org.springframework.web.servlet.config.annotation.WebMvcConfigurer;

import java.lang.reflect.Type; import java.nio.charset.StandardCharsets; import java.time.LocalDate; import java.time.LocalDateTime; import java.time.format.DateTimeFormatter; import java.util.Collections; import java.util.List;

@Configuration @EnableWebMvc public class MyWebMvcConfigurer implements WebMvcConfigurer {

@Override
public void configureMessageConverters(List<HttpMessageConverter<?>> converters) {
    FastJsonConfig config = new FastJsonConfig();
    
    config.setDateFormat("yyyy-MM-dd HH:mm:ss");
    
    config.setReaderFeatures(JSONReader.Feature.FieldBased, JSONReader.Feature.SupportArrayToBean, JSONReader.Feature.SupportAutoType);
    config.setWriterFeatures(JSONWriter.Feature.WriteMapNullValue, JSONWriter.Feature.WriteNulls);
    
    JSON.register(LocalDateTime.class, MyLocalDateTimeWriter.instance);
    JSON.register(LocalDate.class, MyLocalDateWriter.instance);

    FastJsonHttpMessageConverter converter = new FastJsonHttpMessageConverter();
    converter.setFastJsonConfig(config);
    converter.setDefaultCharset(StandardCharsets.UTF_8);
    converter.setSupportedMediaTypes(Collections.singletonList(MediaType.APPLICATION_JSON));
    converters.add(0, converter);
}

}

class MyLocalDateTimeWriter implements ObjectWriter { static MyLocalDateTimeWriter instance = new MyLocalDateTimeWriter();

@Override
public void write(JSONWriter jsonWriter, Object object, Object fieldName, Type fieldType, long features) {
    if (object == null) {
        jsonWriter.writeNull();
        return;
    }
    LocalDateTime dateTime = (LocalDateTime) object;
    DateTimeFormatter formatter = DateTimeFormatter.ofPattern("yyyy-MM-dd HH:mm:ss");
    String format = formatter.format(dateTime);
    // 优先使用name
    jsonWriter.writeString(format);
}

}

class MyLocalDateWriter implements ObjectWriter { static MyLocalDateWriter instance = new MyLocalDateWriter();

@Override
public void write(JSONWriter jsonWriter, Object object, Object fieldName, Type fieldType, long features) {
    if (object == null) {
        jsonWriter.writeNull();
        return;
    }
    LocalDateTime dateTime = (LocalDateTime) object;
    LocalDate date = dateTime.toLocalDate();
    DateTimeFormatter formatter = DateTimeFormatter.ofPattern("yyyy-MM-dd");
    String format = formatter.format(date);
    // 优先使用name
    jsonWriter.writeString(format);
}

}

原提问者GitHub用户yangcanlin