ClickHouseArray序列化异常

1.异常

Caused by: com.fasterxml.jackson.databind.JsonMappingException: (was java.sql.SQLFeatureNotSupportedException) (through reference chain: com.****.HttpResult["content"]->java.util.ArrayList[0]->java.util.LinkedHashMap["column_14"]->ru.yandex.clickhouse.ClickHouseArray["resultSet"])

使用jdbc操作clickhouse执行sql的返回结果时报错

2.背景知识

controller层使用@RestController时，使用MappingJackson2HttpMessageConverter对返回的数据进行序列化。所以前端可以显示json，xml等格式的数据。而@Controller注解显示的是视图，如果想展示json，要在方法中加上@ResponseBody

3.解决方案

项目中其他语句都没有报错，只有在返回 ClickHouseArray 这个类的时候序列化异常。没有看到其他解法，就自己写了序列化和反序列的代码。

 代码如下：

import com.fasterxml.jackson.core.JsonGenerator;
import com.fasterxml.jackson.core.JsonParser;
import com.fasterxml.jackson.core.JsonProcessingException;
import com.fasterxml.jackson.core.TreeNode;
import com.fasterxml.jackson.databind.DeserializationContext;
import com.fasterxml.jackson.databind.DeserializationFeature;
import com.fasterxml.jackson.databind.JsonDeserializer;
import com.fasterxml.jackson.databind.JsonSerializer;
import com.fasterxml.jackson.databind.ObjectMapper;
import com.fasterxml.jackson.databind.SerializationFeature;
import com.fasterxml.jackson.databind.SerializerProvider;
import com.fasterxml.jackson.databind.module.SimpleModule;
import com.fasterxml.jackson.databind.node.ArrayNode;
import com.fasterxml.jackson.databind.node.TextNode;
import lombok.SneakyThrows;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.http.converter.HttpMessageConverter;
import org.springframework.http.converter.json.MappingJackson2HttpMessageConverter;
import org.springframework.web.servlet.config.annotation.WebMvcConfigurer;
import ru.yandex.clickhouse.ClickHouseArray;
import ru.yandex.clickhouse.domain.ClickHouseDataType;
import java.io.IOException;
import java.util.List;
@Configuration
public class WebMvcConfiguration implements WebMvcConfigurer {
@Override
public void configureMessageConverters(List<HttpMessageConverter<?>> converters) {
converters.add(mappingJackson2HttpMessageConverter());
WebMvcConfigurer.super.configureMessageConverters(converters);
}
@Bean
public MappingJackson2HttpMessageConverter mappingJackson2HttpMessageConverter() {
MappingJackson2HttpMessageConverter jsonConverter = new MappingJackson2HttpMessageConverter();
//设置解析JSON工具类
ObjectMapper objectMapper = new ObjectMapper();
//解决空属性报错
objectMapper.configure(SerializationFeature.FAIL_ON_EMPTY_BEANS, false);
//忽略未知属性 防止解析报错
objectMapper.configure(DeserializationFeature.FAIL_ON_UNKNOWN_PROPERTIES, false);
// 全局clickhouseArray序列化配置
SimpleModule module = new SimpleModule();
//module.addDeserializer(ru.yandex.clickhouse.ClickHouseArray.class,new ClickHouseArrayDeserializer());
module.addSerializer(ru.yandex.clickhouse.ClickHouseArray.class,new ClickHouseArraySerialize());
objectMapper.registerModule(module);
objectMapper.findAndRegisterModules();
jsonConverter.setObjectMapper(objectMapper);
return jsonConverter;
}
public class ClickHouseArraySerialize extends JsonSerializer<ClickHouseArray> {
@SneakyThrows
@Override
public void serialize(ClickHouseArray clickHouseArray, JsonGenerator jsonGenerator, SerializerProvider serializerProvider) throws IOException {
// 对象转为字节流
jsonGenerator.writeStartObject();
jsonGenerator.writeStringField("elementType",clickHouseArray.getBaseTypeName());
jsonGenerator.writeObjectField("array",clickHouseArray.getArray());
jsonGenerator.writeEndObject();
}
}
}

最后

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