json is often used in projects, such as fastjson, Jackson, and so on. Sometimes for uniformity, we usually agree to use one. Either way, when Spring MVC returns data of the previous Long type, js loses precision in obtaining the data, which results in inaccurate data. The solution is to convert Long type data to String type when serializing. When using Spring MVC's default Jackson, we can do this:

@Configuration
public class WebConfig extends WebMvcConfigurerAdapter {

    @Override
    public void configureMessageConverters(List<HttpMessageConverter<?>> converters) {
        MappingJackson2HttpMessageConverter jackson2HttpMessageConverter = 
        new MappingJackson2HttpMessageConverter();

        ObjectMapper objectMapper = new ObjectMapper();
        SimpleModule simpleModule = new SimpleModule();
        simpleModule.addSerializer(BigInteger.class, ToStringSerializer.instance);
        simpleModule.addSerializer(Long.class, ToStringSerializer.instance);
        simpleModule.addSerializer(Long.TYPE, ToStringSerializer.instance);
        objectMapper.registerModule(simpleModule);
        jackson2HttpMessageConverter.setObjectMapper(objectMapper);
        converters.add(jackson2HttpMessageConverter);
        converters.add(new StringHttpMessageConverter(Charset.forName("UTF-8")));
    }

}

Of course, there may be times when fastjson is used as a unified convention in a project, but Jackson is used by default in Spring MVC There are two general ways to replace Jackson with fastjson in Spring Boot:

First:

@Configuration
public class WebConfig extends WebMvcConfigurerAdapter {

    @Bean
    public HttpMessageConverters fastJsonHttpMessageConverter() {
        return new HttpMessageConverters(new FastJsonHttpMessageConverter());
    }
}

Second:

@Configuration
public class WebConfig extends WebMvcConfigurerAdapter {

    @Override
    public void configureMessageConverters(List<HttpMessageConverter<?>> converters) {
        FastJsonHttpMessageConverter fastConverter = 
        new FastJsonHttpMessageConverter();

        FastJsonConfig fastJsonConfig = new FastJsonConfig();
        fastJsonConfig.setSerializerFeatures(SerializerFeature.PrettyFormat);
        fastConverter.setFastJsonConfig(fastJsonConfig);
        converters.add(fastConverter);
    }
}

After replacing it with fastjson, we can do something about the loss of precision:

@Configuration
public class WebConfig extends WebMvcConfigurerAdapter {

    @Override
    public void configureMessageConverters(List<HttpMessageConverter<?>> converters) {
        FastJsonHttpMessageConverter fastConverter = 
        new FastJsonHttpMessageConverter();

        FastJsonConfig fastJsonConfig = new FastJsonConfig();
        SerializeConfig serializeConfig = SerializeConfig.globalInstance;
        serializeConfig.put(BigInteger.class, ToStringSerializer.instance);
        serializeConfig.put(Long.class, ToStringSerializer.instance);
        serializeConfig.put(Long.TYPE, ToStringSerializer.instance);
        fastJsonConfig.setSerializeConfig(serializeConfig);
        fastConverter.setFastJsonConfig(fastJsonConfig);
        converters.add(fastConverter);
    }
}

I think the other way, how to do it should also be clear to everyone, let's not say more here. It is important to note that the version of fastjson used here is 1.2.31, with slightly different versions and modes.

Author: Felixu Links: https://www.jianshu.com/p/7b5e4c443972 Source: Short Book Copyright belongs to the author.For commercial reprinting, please contact the author for authorization. For non-commercial reprinting, please indicate the source.