系列一、SpringBoot统一格式化日期 & 将long型数字转换成字符串

YYAugenstern

已于 2024-01-08 12:49:27 修改

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分类专栏： SpringBoot系列文章标签： spring boot java mybatis

于 2023-05-30 00:47:06 首次发布

本文链接：https://blog.youkuaiyun.com/HelloWorld20161112/article/details/130939174

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当数据库中的bigint类型数据通过接口传递给Vue前端时，出现了精度丢失。解决方案是通过在SpringBoot后端配置Jackson转换器，将Long类型序列化为String，以及对日期进行格式化处理，确保数据正确传输。

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一、现象描述

数据库中的字段保存的是bigint类型的数据，前端vue通过接口获取数据时，该字段的值却丢失精度了，如下图所示：

二、解决方案

2.1、导入依赖

<dependency>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-json</artifactId>
</dependency>

2.2、Constants.java

public class Constants {
    public static String DEFAULT_DATE_TIME_FORMAT = "yyyy-MM-dd HH:mm:ss";
    public static String DEFAULT_DATE_FORMAT = "yyyy-MM-dd";
    public static String DEFAULT_TIME_FORMAT = "HH:mm:ss";
}

2.3、配置转换器

package org.star.config;

import com.fasterxml.jackson.databind.DeserializationFeature;
import com.fasterxml.jackson.databind.ObjectMapper;
import com.fasterxml.jackson.databind.SerializationFeature;
import com.fasterxml.jackson.databind.module.SimpleModule;
import com.fasterxml.jackson.databind.ser.std.ToStringSerializer;
import com.fasterxml.jackson.datatype.jsr310.JavaTimeModule;
import com.fasterxml.jackson.datatype.jsr310.deser.LocalDateDeserializer;
import com.fasterxml.jackson.datatype.jsr310.deser.LocalDateTimeDeserializer;
import com.fasterxml.jackson.datatype.jsr310.deser.LocalTimeDeserializer;
import com.fasterxml.jackson.datatype.jsr310.ser.LocalDateSerializer;
import com.fasterxml.jackson.datatype.jsr310.ser.LocalDateTimeSerializer;
import com.fasterxml.jackson.datatype.jsr310.ser.LocalTimeSerializer;
import com.fasterxml.jackson.module.paramnames.ParameterNamesModule;
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.EnableWebMvc;
import org.springframework.web.servlet.config.annotation.WebMvcConfigurer;
import org.star.constant.Constants;

import java.time.LocalDate;
import java.time.LocalDateTime;
import java.time.LocalTime;
import java.time.format.DateTimeFormatter;
import java.util.List;


@Configuration
@EnableWebMvc
public class MyWebMvcConfigurer implements WebMvcConfigurer {

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

        /**
         * 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
         */
        ObjectMapper objectMapper =objectMapper();
        SimpleModule simpleModule =new SimpleModule();
        simpleModule.addSerializer(Long.class, ToStringSerializer.instance);
        simpleModule.addSerializer(Long.TYPE, ToStringSerializer.instance);
        objectMapper.registerModule(simpleModule);
        jackson2HttpMessageConverter.setObjectMapper(objectMapper);
        converters.add(jackson2HttpMessageConverter);

    }

    /**
     * 格式化日期
     * @return
     */
    @Bean
    public ObjectMapper objectMapper() {
        ObjectMapper objectMapper = new ObjectMapper();
        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(Constants.DEFAULT_DATE_TIME_FORMAT)));
        javaTimeModule.addSerializer(LocalDate.class,new LocalDateSerializer(DateTimeFormatter.ofPattern(Constants.DEFAULT_DATE_FORMAT)));
        javaTimeModule.addSerializer(LocalTime.class,new LocalTimeSerializer(DateTimeFormatter.ofPattern(Constants.DEFAULT_TIME_FORMAT)));
        javaTimeModule.addDeserializer(LocalDateTime.class,new LocalDateTimeDeserializer(DateTimeFormatter.ofPattern(Constants.DEFAULT_DATE_TIME_FORMAT)));
        javaTimeModule.addDeserializer(LocalDate.class,new LocalDateDeserializer(DateTimeFormatter.ofPattern(Constants.DEFAULT_DATE_FORMAT)));
        javaTimeModule.addDeserializer(LocalTime.class,new LocalTimeDeserializer(DateTimeFormatter.ofPattern(Constants.DEFAULT_TIME_FORMAT)));
        objectMapper.registerModule(javaTimeModule).registerModule(new ParameterNamesModule());
        return objectMapper;
    }

}

2.4、效果

2.5、参考

https://www.bilibili.com/read/cv22828897/
https://www.jianshu.com/p/cf50c4bc71d3
https://www.cnblogs.com/exmyth/p/14305299.html（靠谱[推荐]）
http://www.shouxicto.com/article/2858.html（靠谱[不推荐]）