SpringBoot中Jackson日期格式化的方法

Jackson 日期格式化技巧

使用 Spring Boot 时，需要使用 Jackson 处理一些 Java Time API 类型的 JSON 序列化问题，在处理一些类的字段时，可以通过直接在属性上加注解的方式来指定其格式化样式。但是，昨天同事遇到一个格式化 Map 数据的问题，这样就不能通过加注解来解决格式化样式的问题了。

在网上各种搜索，各种尝试后，终于解决了这个问题，记录一下，以备不时之需。

闲言少叙，直接上代码：

package com.diguage.demo.config;
import com.fasterxml.jackson.databind.ObjectMapper;
import com.fasterxml.jackson.databind.util.StdDateFormat;
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.ser.LocalDateSerializer;
import com.fasterxml.jackson.datatype.jsr310.ser.LocalDateTimeSerializer;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.context.annotation.Primary;
import java.text.DateFormat;
import java.text.SimpleDateFormat;
import java.time.LocalDate;
import java.time.LocalDateTime;
import static com.fasterxml.jackson.databind.SerializationFeature.*;
import static java.time.format.DateTimeFormatter.ofPattern;
/
 * 配置类
 *
 * @author D瓜哥 · https://www.diguage.com
 */
@Configuration
public class Config {
    /
     * 创建 ObjectMapper 对象，配置日期格式化
     *
     * @author D瓜哥 · https://www.diguage.com
     */
    @Bean
    @Primary
    public ObjectMapper objectMapper() {
        ObjectMapper mapper = new ObjectMapper();
        String dateTimepattern = "yyyy-MM-dd HH:mm:ss";
        String datePattern = "yyyy-MM-dd";
        DateFormat dateFormat = new SimpleDateFormat(dateTimepattern);
        mapper.setDateFormat(dateFormat);
        mapper.configure(WRITE_DATES_AS_TIMESTAMPS, false);
        mapper.setDateFormat(new StdDateFormat().withColonInTimeZone(true));
        JavaTimeModule javaTimeModule = new JavaTimeModule();
        javaTimeModule.addDeserializer(LocalDate.class,
                new LocalDateDeserializer(ofPattern(datePattern)));
        javaTimeModule.addSerializer(LocalDate.class,
                new LocalDateSerializer(ofPattern(datePattern)));
        javaTimeModule.addDeserializer(LocalDateTime.class,
                new LocalDateTimeDeserializer(ofPattern(dateTimepattern)));
        javaTimeModule.addSerializer(LocalDateTime.class,
                new LocalDateTimeSerializer(ofPattern(dateTimepattern)));
        mapper.registerModule(javaTimeModule);
        return mapper;
    }
}

后续问题

不知道通过这种方式指定日期格式化样式后，在处理一些打格式化样式注解的字段时，会有什么样的表现？有机会测试一下。

补充：Jackson 统一配置 日期转换格式

方式一:配置文件yml中配置

spring:
    jackson:
        default-property-inclusion: ALWAYS
        time-zone: GMT+8
        date-format: yyyy-MM-dd HH:mm:ss

这样序列化后，Date类型会被格式化成配置中的格式。

方式二:配置类中配置创建JacksonConfig.java

@Configuration
public class JacksonConfig {

    @Bean
    @Order(Ordered.HIGHEST_PRECEDENCE)
    public Jackson2ObjectMapperBuilderCustomizer customJackson() {
        return new Jackson2ObjectMapperBuilderCustomizer() {
            @Override
            public void customize(Jackson2ObjectMapperBuilder builder) {
                builder.serializerByType(LocalDateTime.class,
                        new LocalDateTimeSerializer(DateTimeFormatter.ofPattern("yyyy-MM-dd HH:mm:ss")));
                builder.serializerByType(LocalDate.class,
                        new LocalDateSerializer(DateTimeFormatter.ofPattern("yyyy-MM-dd")));
                builder.serializerByType(LocalTime.class,
                        new LocalTimeSerializer(DateTimeFormatter.ofPattern("HH:mm:ss")));
                builder.deserializerByType(LocalDateTime.class,
                        new LocalDateTimeDeserializer(DateTimeFormatter.ofPattern("yyyy-MM-dd HH:mm:ss")));
                builder.deserializerByType(LocalDate.class,
                        new LocalDateDeserializer(DateTimeFormatter.ofPattern("yyyy-MM-dd")));
                builder.deserializerByType(LocalTime.class,
                        new LocalTimeDeserializer(DateTimeFormatter.ofPattern("HH:mm:ss")));
                builder.serializationInclusion(JsonInclude.Include.NON_NULL);
                builder.failOnUnknownProperties(false);
                builder.featuresToDisable(SerializationFeature.WRITE_DATES_AS_TIMESTAMPS);
            }
        };
    }
}