Lombok + Swagger2 +Jackson 属性第二个字母为大写，序列化后字段第二个字母为小写

文章目录

- 一、问题概述
- 二、原因分析：

一、问题概述

原来SpringBoot 项目中采用的FastJson 转换器，配合Swagger2 + lombok 序列化后字段大小写正常，但是当换成fastJson 后，如果原来实体里面第二字母为大写则在swagger 文档里及接口返回的字段都给自动变为了小写。

原来fastJson 配置：

java 复制代码

import com.alibaba.fastjson.serializer.SerializerFeature;
import com.alibaba.fastjson.support.config.FastJsonConfig;
import com.alibaba.fastjson.support.spring.FastJsonHttpMessageConverter;
import org.springframework.boot.autoconfigure.http.HttpMessageConverters;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.http.MediaType;
import org.springframework.http.converter.HttpMessageConverter;

import java.util.ArrayList;
import java.util.List;

@Configuration
public class FastJSONConfig {
    @Bean
    public HttpMessageConverters fastJsonHttpMessageConverters(){
        //1.需要定义一个convert转换消息的对象;
        FastJsonHttpMessageConverter fastJsonHttpMessageConverter = new FastJsonHttpMessageConverter();
        //2:添加fastJson的配置信息;
        FastJsonConfig fastJsonConfig = new FastJsonConfig();
        /**
         * TODO 第一个SerializerFeature.PrettyFormat可以省略，毕竟这会造成额外的内存消耗和流量，第二个是用来指定当属性值为null是是否输出：pro:null
         　　　　　 * SerializerFeature.SkipTransientField
         */
        fastJsonConfig.setSerializerFeatures(SerializerFeature.WriteMapNullValue);
        fastJsonConfig.setSerializerFeatures(SerializerFeature.WriteDateUseDateFormat);
        //3处理中文乱码问题
        List<MediaType> fastMediaTypes = new ArrayList<>();
        fastMediaTypes.add(MediaType.APPLICATION_JSON_UTF8);
        //4.在convert中添加配置信息.
        fastJsonHttpMessageConverter.setSupportedMediaTypes(fastMediaTypes);
        fastJsonHttpMessageConverter.setFastJsonConfig(fastJsonConfig);
        HttpMessageConverter<?> converter = fastJsonHttpMessageConverter;
        return new HttpMessageConverters(converter);
    }

}

二、原因分析：

jackson 转换器配置不正确导致的，需要再jacksonConfig 里面添加

java 复制代码

        objectMapper.setVisibility(objectMapper.getSerializationConfig().getDefaultVisibilityChecker()
                .withFieldVisibility(JsonAutoDetect.Visibility.ANY)
                .withGetterVisibility(JsonAutoDetect.Visibility.NONE)
                .withSetterVisibility(JsonAutoDetect.Visibility.NONE)
                .withCreatorVisibility(JsonAutoDetect.Visibility.NONE));

完整配置：

java 复制代码

@Configuration
@ConditionalOnClass(ObjectMapper.class)
public class JacksonConfig {

    /**
     * 创建Jackson对象映射器
     *
     * @param builder Jackson对象映射器构建器
     * @return ObjectMapper
     */
    @Bean
    @Primary
    @ConditionalOnMissingBean(ObjectMapper.class)
    public ObjectMapper getJacksonObjectMapper(Jackson2ObjectMapperBuilder builder) {
        ObjectMapper objectMapper = builder.createXmlMapper(false).build();
        // 属性为""或null时不序列化。
//        objectMapper.setSerializationInclusion(JsonInclude.Include.NON_NULL);
        //序列换成json时,将所有的long变成string.因为js中得数字类型不能包含所有的java long值，超过16位后会出现精度丢失
        SimpleModule simpleModule = new SimpleModule();
        simpleModule.addSerializer(Long.class, com.fasterxml.jackson.databind.ser.std.ToStringSerializer.instance);
        simpleModule.addSerializer(Long.TYPE, com.fasterxml.jackson.databind.ser.std.ToStringSerializer.instance);
        objectMapper.registerModule(simpleModule);
        //反序列化的时候如果多了其他属性,不抛出异常
        objectMapper.disable(DeserializationFeature.FAIL_ON_UNKNOWN_PROPERTIES);
        objectMapper.disable(SerializationFeature.FAIL_ON_EMPTY_BEANS);
        objectMapper.configure(JsonParser.Feature.ALLOW_SINGLE_QUOTES, true);
        // 字段保留， 将null转为""
        objectMapper.getSerializerProvider().setNullValueSerializer(new JsonSerializer<Object>() {
            @Override
            public void serialize(Object value, JsonGenerator gen, SerializerProvider serializers) throws IOException {
                gen.writeString("");
            }
        });
        //日期格式处理
        objectMapper.setDateFormat(new SimpleDateFormat("yyyy-MM-dd HH:mm:ss"));

        objectMapper.disable(SerializationFeature.WRITE_DATES_AS_TIMESTAMPS);
        objectMapper.disable(DeserializationFeature.ADJUST_DATES_TO_CONTEXT_TIME_ZONE);
        JavaTimeModule javaTimeModule = new JavaTimeModule();
        javaTimeModule.addSerializer(LocalDateTime.class, new LocalDateTimeSerializer(DateTimeFormatter.ofPattern("yyyy-MM-dd HH:mm:ss")));
        javaTimeModule.addSerializer(LocalDate.class, new LocalDateSerializer(DateTimeFormatter.ofPattern("yyyy-MM-dd")));
        javaTimeModule.addSerializer(LocalTime.class, new LocalTimeSerializer(DateTimeFormatter.ofPattern("HH:mm:ss")));
        javaTimeModule.addDeserializer(LocalDateTime.class, new LocalDateTimeDeserializer(DateTimeFormatter.ofPattern("yyyy-MM-dd HH:mm:ss")));
        javaTimeModule.addDeserializer(LocalDate.class, new LocalDateDeserializer(DateTimeFormatter.ofPattern("yyyy-MM-dd")));
        javaTimeModule.addDeserializer(LocalTime.class, new LocalTimeDeserializer(DateTimeFormatter.ofPattern("HH:mm:ss")));
        objectMapper.registerModule(javaTimeModule);

        objectMapper.setVisibility(objectMapper.getSerializationConfig().getDefaultVisibilityChecker()
                .withFieldVisibility(JsonAutoDetect.Visibility.ANY)
                .withGetterVisibility(JsonAutoDetect.Visibility.NONE)
                .withSetterVisibility(JsonAutoDetect.Visibility.NONE)
                .withCreatorVisibility(JsonAutoDetect.Visibility.NONE));



        return objectMapper;
    }

}