SpringBoot中关于时间显示格式的处理

曾经终败给现在 2024-03-26 00:05 46阅读 0赞

> [Java知识点总结：想看的可以从这里进入][Java]

#### 目录 ####

*   *   *  2.21、时间问题

#### 2.21、时间问题 ####

我们从数据库获取的时间，在显示中可能是这样的

![image-20230321120136207][]

所以我们需要在实体类中使用注解`@DateTimeFormat（用于前台传递到后台）`和`@JsonFormat（后台传递到前台）`，来修改时间的格式（`推荐使用 JDK8 中增加的LocalDateTime接受数据库DateTime类型的数据`。）

/**
    * 创建时间
    */
    @DateTimeFormat(pattern = "yyyy-MM-dd HH:mm:ss")
    @JsonFormat(locale = "zh", timezone = "GMT+8", pattern = "yyyy-MM-dd HH:mm:ss")
    private LocalDateTime gmtCreate;
    
    /**
    * 修改时间
    */
    @DateTimeFormat(pattern = "yyyy-MM-dd HH:mm:ss")
    @JsonFormat(locale = "zh", timezone = "GMT+8", pattern = "yyyy-MM-dd HH:mm:ss")
    private LocalDateTime gmtModified;

![image-20230321120305843][]

当然不想每个实体类都添加注解的话，也可以配置全局生效。(@JsonFormat的优先级更高，配置了@JsonFormat后，全局的不生效)

*  添加注解
    
        <dependency>
            <groupId>com.fasterxml.jackson.core</groupId>
            <artifactId>jackson-annotations</artifactId>
        </dependency>
        
        <dependency>
            <groupId>com.fasterxml.jackson.datatype</groupId>
            <artifactId>jackson-datatype-jsr310</artifactId>
        </dependency>
 *  编写配置类
    
        @Configuration
        public class UnifiedTimeProcessing {
              
            /** LocalDateTime的格式 */
            public static final String DATE_TIME_FORMAT = "yyyy-MM-dd HH:mm:ss";
            /** LocalDate的格式 */
            public static final String DATE_FORMAT = "yyyy-MM-dd";
            /** LocalTime的格式 */
            public static final String TIME_FORMAT = "HH:mm:ss";
        
            /**
             * LocalDate转换器
             */
            @Bean
            public Converter<String, LocalDate> localDateConverter() {
              
                return new Converter<>() {
              
                    @Override
                    public LocalDate convert(String source) {
              
                        if (StringUtils.isEmpty(source)) {
              
                            return null;
                        }
                        return LocalDate.parse(source, DateTimeFormatter.ofPattern(DATE_FORMAT));
        
                    }
                };
            }
        
            /**
             * LocalDateTime转换器
             */
            @Bean
            public Converter<String, LocalDateTime> localDateTimeConverter() {
              
                return new Converter<>() {
              
                    @Override
                    public LocalDateTime convert(String source) {
              
                        if (StringUtils.isEmpty(source)) {
              
                            return null;
                        }
                        return LocalDateTime.parse(source, DateTimeFormatter.ofPattern(DATE_TIME_FORMAT));
                    }
                };
            }
        
            /**
             * LocalTime转换器
             */
            @Bean
            public Converter<String, LocalTime> localTimeConverter() {
              
                return new Converter<>() {
              
                    @Override
                    public LocalTime convert(String source) {
              
                        if (StringUtils.isEmpty(source)) {
              
                            return null;
                        }
                        return LocalTime.parse(source, DateTimeFormatter.ofPattern(TIME_FORMAT));
                    }
                };
            }
        
            /**
             * 后台到前端 Json序列化转换器
             */
            @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(DATE_TIME_FORMAT)));
                javaTimeModule.addSerializer(LocalDate.class,
                        new LocalDateSerializer(DateTimeFormatter.ofPattern(DATE_FORMAT)));
                javaTimeModule.addSerializer(LocalTime.class,
                        new LocalTimeSerializer(DateTimeFormatter.ofPattern(TIME_FORMAT)));
        
                objectMapper.registerModule(javaTimeModule);
                return objectMapper;
            }
        }

[Java]: https://blog.csdn.net/yuandfeng/article/details/114333525
[image-20230321120136207]: https://image.dandelioncloud.cn/pgy_files/images/2024/03/25/6a17f855fba24b79a6fe1c1afef65f58.png
[image-20230321120305843]: https://image.dandelioncloud.cn/pgy_files/images/2024/03/25/fccf8a5f88a148428785fa8e06bcb352.png