如何处理Long类型精度丢失问题?

电玩女神 2023-09-30 08:51 15阅读 0赞

> 当实体类中的字段为`Long`类型，且值超过前端`js`显示的长度范围时会导致前端回显错误。

## 方法1、使用`JsonSerialize`注解序列化的时候把Long自动转为`String`（单个属性） ##

import com.fasterxml.jackson.databind.annotation.JsonSerialize;
    import com.fasterxml.jackson.databind.ser.std.ToStringSerializer;
    
    @JsonSerialize(using = ToStringSerializer.class)
    private Long xxx;

## 方法2、添加`JacksonConfig`配置全局序列化（全部属性） ##

package com.framework.config;
    
    import org.springframework.context.annotation.Bean;
    import org.springframework.context.annotation.Configuration;
    import org.springframework.http.converter.json.Jackson2ObjectMapperBuilder;
    import org.springframework.http.converter.json.MappingJackson2HttpMessageConverter;
    import com.fasterxml.jackson.annotation.JsonInclude;
    import com.fasterxml.jackson.databind.MapperFeature;
    import com.fasterxml.jackson.databind.ObjectMapper;
    import com.fasterxml.jackson.databind.module.SimpleModule;
    import com.fasterxml.jackson.databind.ser.std.ToStringSerializer;
    
    /**
     * Jackson配置
     *
     */
    @Configuration
    public class JacksonConfig
    {
        @Bean
        public MappingJackson2HttpMessageConverter jackson2HttpMessageConverter()
        {
            final Jackson2ObjectMapperBuilder builder = new Jackson2ObjectMapperBuilder();
            builder.serializationInclusion(JsonInclude.Include.NON_NULL);
            final ObjectMapper objectMapper = builder.build();
            SimpleModule simpleModule = new SimpleModule();
            // Long 转为 String 防止 js 丢失精度
            simpleModule.addSerializer(Long.class, ToStringSerializer.instance);
            objectMapper.registerModule(simpleModule);
            // 忽略 transient 关键词属性
            objectMapper.configure(MapperFeature.PROPAGATE_TRANSIENT_MARKER, true);
            return new MappingJackson2HttpMessageConverter(objectMapper);
        }
    }