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Json数据问题

Posted on Valine:
Symbols count in article: 3.5k Reading time ≈ 3 mins.

FastJson使用

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@SpringBootApplication
@MapperScan("tech.xixing.huaxuemall.mapper")
public class HuaxuemallApplication {

    public static void main(String[] args) {
        SpringApplication.run(HuaxuemallApplication.class, args);
    }

    @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);
        //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);
    }
}

fastJson的循环/重复引用问题

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{
    "data": [
        {
            "brand": {
                "brandName": "罗恩",
                "categories": "1|2|3|",
                "descs": null,
                "id": 1,
                "picture": "https://manager.chem-mall.com/files/brands_mng_logo_1545016241_8626.jpg",
                "sorted": 1,
                "titleId": null
            },
            "productCategoryList": [
                {
                    "casNo": "7647-14-5",
                    "categoryId": 12,
                    "chemicalFormula": "NaCl",
                    "chineseName": "氯化钠",
                    "englishName": "NaCl",
                    "id": 1,
                    "picture": "https://www.chem-mall.com/assets/proimgs/7647-14-5.jpg?1596848355",
                    "sorted": 1
                },
                {
                    "casNo": null,
                    "categoryId": 12,
                    "chemicalFormula": null,
                    "chineseName": "11-马来酰亚胺基十一酸,97%",
                    "englishName": null,
                    "id": 2,
                    "picture": "https://www.chem-mall.com/assets/proimgs/57079-01-3.jpg?1596933930",
                    "sorted": 1
                }
            ]
        },
        {
            "brand": {
                "brandName": "罗恩test",
                "categories": "1|2|3|",
                "descs": null,
                "id": 4,
                "picture": "https://manager.chem-mall.com/files/brands_mng_logo_1545016241_8626.jpg",
                "sorted": 1,
                "titleId": null
            },
            "productCategoryList": [
                {
                    "$ref": "$.data[0].productCategoryList[0]"
                },
                {
                    "$ref": "$.data[0].productCategoryList[1]"
                }
            ]
        }
    ],
    "msg": null,
    "status": 0
}

出现”$ref”: “$.data[0].productCategoryList[0]”

如果是重复引用可以new一个新对象来解决

example：

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//为了防止转json出现引用问题
ProductCategory productCategory1=new ProductCategory();
BeanUtils.copyProperties(productCategory,productCategory1);

productCategories.add(productCategory1);

如果是循环引用：

在配置中加上这句，不过已经被废弃了

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fastJsonHttpMessageConverter.setFeatures(SerializerFeature.DisableCircularReferenceDetect);

可以替换成以下：

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FastJsonConfig fastJsonConfig = new FastJsonConfig();
fastJsonConfig.setSerializerFeatures(SerializerFeature.DisableCircularReferenceDetect);
fastJsonHttpMessageConverter.setFastJsonConfig(fastJsonConfig);