使用 Spring Boot 時，需要使用 Jackson 處理一些 Java Time API 類型的 JSON 序列化問題，在處理一些類的字段時，可以通過直接在屬性上加注解的方式來指定其格式化樣式。但是，昨天同事遇到一個格式化 Map 數(shù)據(jù)的問題，這樣就不能通過加注解來解決格式化樣式的問題了。

在網(wǎng)上各種搜索，各種嘗試后，終于解決了這個問題，記錄一下，以備不時之需。

閑言少敘，直接上代碼：

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>
 * 配置類
 *
 * @author D瓜哥 · <a  rel="external nofollow"  rel="external nofollow"  target="_blank" >https://www.diguage.com</a>
 */
@Configuration
public class Config {
    /</strong>
     * 創(chuàng)建 ObjectMapper 對象，配置日期格式化
     *
     * @author D瓜哥 · <a  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;
    }
}

后續(xù)問題

不知道通過這種方式指定日期格式化樣式后，在處理一些打格式化樣式注解的字段時，會有什么樣的表現(xiàn)？有機(jī)會測試一下。

補(bǔ)充：Jackson 統(tǒng)一配置日期轉(zhuǎn)換格式

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

這樣序列化后，Date類型會被格式化成配置中的格式。

方式二:配置類中配置創(chuàng)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);
            }
        };
    }
}