Jackson date formatting method in SpringBoot

Jackson date formatting skills

When using Spring Boot, you need to use Jackson to handle some Java Time API type JSON serialization issues. When processing fields of some classes, you can add annotations directly to the properties. way to specify its formatting style. However, yesterday, a colleague encountered a problem with formatting Map data, so the formatting style problem could not be solved by adding annotations.

After various searches on the Internet and various attempts, I finally solved this problem and recorded it in case of emergency.

No further talk, let’s go directly to the code:

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;
/<strong>
 * 配置类
 *
 * @author D瓜哥 · <a href="https://www.diguage.com/" rel="external nofollow"  rel="external nofollow"  target="_blank" >https://www.diguage.com</a>
 */
@Configuration
public class Config {
    /</strong>
     * 创建 ObjectMapper 对象，配置日期格式化
     *
     * @author D瓜哥 · <a href="https://www.diguage.com/" rel="external nofollow"  rel="external nofollow"  target="_blank" >https://www.diguage.com</a>
     */
    @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;
    }
}

Follow-up questions

I don’t know how to deal with some formatting styles after specifying the date formatting style in this way. What kind of behavior will there be when annotating fields? Have a chance to test it out.

Supplement: Jackson unified configuration date conversion format

Method 1: Configure in the configuration file yml

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

After serialization, the Date type will be Format to the format in the configuration.

Method 2: Configuration in configuration classCreate 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);
            }
        };
    }
}

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