JsonSerializerManage返回结果转换

原创已于 2023-03-17 15:06:39 修改 · 254 阅读

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#java #spring #spring boot

于 2022-09-13 09:52:52 首次发布

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该博客主要介绍了如何在Spring Boot中配置Jackson ObjectMapper，实现JSON序列化时忽略null值并输出空字符串，以及将Long类型转换为String以避免精度丢失。此外，还涉及日期格式化的设置。

package com.byyl.web.config;

import com.fasterxml.jackson.annotation.JsonInclude;
import com.fasterxml.jackson.core.JsonGenerator;
import com.fasterxml.jackson.databind.JsonSerializer;
import com.fasterxml.jackson.databind.ObjectMapper;
import com.fasterxml.jackson.databind.SerializerProvider;
import com.fasterxml.jackson.databind.module.SimpleModule;
import com.fasterxml.jackson.databind.ser.std.ToStringSerializer;
import org.springframework.boot.jackson.JsonComponent;
import org.springframework.context.annotation.Bean;
import org.springframework.http.converter.json.Jackson2ObjectMapperBuilder;

import java.io.IOException;

@JsonComponent
public class JsonSerializerManage {
    @Bean
    public ObjectMapper jacksonObjectMapper(Jackson2ObjectMapperBuilder builder) {
        ObjectMapper objectMapper = builder.createXmlMapper(false).build();
        /**
         * 忽略value为null 时 key的输出
         */
        //objectMapper.setSerializationInclusion(JsonInclude.Include.NON_NULL);
        /**
         * value为null 时 输出空字符串
         */
        objectMapper.getSerializerProvider().setNullValueSerializer(new JsonSerializer<Object>() {
            @Override
            public void serialize(Object value, JsonGenerator gen, SerializerProvider serializers) throws IOException {
                gen.writeString("");
            }
        });

        /**
         * 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
         */
        SimpleModule module = new SimpleModule();
        module.addSerializer(Long.class, ToStringSerializer.instance);
        module.addSerializer(Long.TYPE, ToStringSerializer.instance);
        objectMapper.registerModule(module);
        /**
         * 日期格式化
         * 处理默认日期格式化：yyyy-MM-dd HH:mm:ss
         */
//        objectMapper.configure(SerializationFeature.WRITE_DATES_AS_TIMESTAMPS, false);
//        objectMapper.configure(DeserializationFeature.FAIL_ON_UNKNOWN_PROPERTIES, false);
//        objectMapper.setDateFormat(new SimpleDateFormat("yyyy-MM-dd"));

        return objectMapper;
    }

}