Date Formatting Techniques in Spring Boot Applications

Common Application Scenarios

Unified date formats improve readability and maintainability when different systems exchange data, especially in front‑end/back‑end separation, database storage, and log recording.

Common Date Formatting Methods

Frontend Time Formatting

When the back‑end delegates formatting to the front‑end, a JavaScript utility function can be used:

function dateFormat(fmt, date) {
    let ret;
    const opt = {
        "Y+": date.getFullYear().toString(),
        "m+": (date.getMonth() + 1).toString(),
        "d+": date.getDate().toString(),
        "H+": date.getHours().toString(),
        "M+": date.getMinutes().toString(),
        "S+": date.getSeconds().toString()
    };
    for (let k in opt) {
        ret = new RegExp("(" + k + ")").exec(fmt);
        if (ret) {
            fmt = fmt.replace(ret[1], (ret[1].length == 1) ? (opt[k]) : (opt[k].padStart(ret[1].length, "0")));
        }
    }
    return fmt;
}
let date = new Date();
dateFormat("YYYY-mm-dd HH:MM:SS", date); // >>>2021-07-25 21:45:12

SimpleDateFormat Formatting

For JDK 8 and earlier, SimpleDateFormat formats Date objects:

// Define formatter
SimpleDateFormat dateFormat = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
// Format a Date instance
String date = dateFormat.format(new Date());

In a Spring controller, the formatter can be applied to each entity field:

@RequestMapping("/list")
public List
getList() {
    SimpleDateFormat dateFormat = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
    List
list = userMapper.getList();
    list.forEach(item -> {
        item.setCtime(dateFormat.format(item.getCreatetime()));
        item.setUtime(dateFormat.format(item.getUpdatetime()));
    });
    return list;
}

DateTimeFormatter Formatting

Since JDK 8, DateTimeFormatter replaces SimpleDateFormat and is thread‑safe:

@RequestMapping("/list")
public List
getList() {
    DateTimeFormatter dateFormat = DateTimeFormatter.ofPattern("yyyy-MM-dd HH:mm:ss");
    List
list = userMapper.getList();
    list.forEach(item -> {
        item.setCtime(dateFormat.format(item.getCreatetime()));
        item.setUtime(dateFormat.format(item.getUpdatetime()));
    });
    return list;
}

Global Time Formatting via Configuration

Adding two lines to application.properties (or application.yml ) makes Jackson format all date fields globally:

# Global date format
spring.jackson.date-format=yyyy-MM-dd HH:mm:ss
# Time zone
spring.jackson.time-zone=GMT+8

Jackson automatically applies this format when serializing response objects.

Partial Formatting with @JsonFormat

Annotate specific fields in an entity to control their format:

import com.fasterxml.jackson.annotation.JsonFormat;
import lombok.Data;
import java.util.Date;

@Data
public class UserInfo {
    private int id;
    private String username;
    @JsonFormat(pattern = "yyyy-MM-dd hh:mm:ss", timezone = "GMT+8")
    private Date createtime;
    private Date updatetime;
}

Custom Parameter Converters

Implement Converter<String, LocalDate> or Converter<String, LocalDateTime> to parse incoming strings:

@Configuration
public class DateConverterConfig {
    @Bean
    public Converter
localDateConverter() {
        return source -> LocalDate.parse(source, DateTimeFormatter.ofPattern("yyyy-MM-dd"));
    }
    @Bean
    public Converter
localDateTimeConverter() {
        return source -> LocalDateTime.parse(source, DateTimeFormatter.ofPattern("yyyy-MM-dd HH:mm:ss"));
    }
}

Using @DateTimeFormat Annotation

Apply @DateTimeFormat on a field to convert a string to a date type:

@DateTimeFormat(pattern = "yyyy-MM-dd HH:mm:ss")
private Date birthday;

ControllerAdvice with initBinder

Define a global binder to convert string parameters to LocalDateTime :

@ControllerAdvice
public class InitBinderDateController {
    @InitBinder("date")
    public void initBinder(WebDataBinder binder) {
        binder.registerCustomEditor(LocalDateTime.class, new PropertyEditorSupport() {
            @Override
            public void setAsText(String text) {
                if (!StringUtils.isEmpty(text)) {
                    setValue(LocalDateTime.parse(text, DateTimeFormatter.ofPattern("yyyy-MM-dd HH:mm:ss")));
                }
            }
        });
    }
}

Backend Global Settings via Beans

Configure Jackson serializers/deserializers for LocalDateTime in a @Configuration class:

@Configuration
public class LocalDateTimeSerializerConfig {
    private static final String PATTERN = "yyyy-MM-dd HH:mm:ss";
    @Bean
    public LocalDateTimeSerializer localDateTimeSerializer() {
        return new LocalDateTimeSerializer(DateTimeFormatter.ofPattern(PATTERN));
    }
    @Bean
    public LocalDateTimeDeserializer localDateTimeDeserializer() {
        return new LocalDateTimeDeserializer(DateTimeFormatter.ofPattern(PATTERN));
    }
    @Bean
    public Jackson2ObjectMapperBuilderCustomizer jackson2ObjectMapperBuilderCustomizer() {
        return builder -> {
            builder.serializerByType(LocalDateTime.class, localDateTimeSerializer());
            builder.deserializerByType(LocalDateTime.class, localDateTimeDeserializer());
        };
    }
}

Returning Timestamps

Configure Spring Boot to output dates as Unix timestamps and expose them via a simple REST endpoint:

# application.properties
spring.mvc.format.date=unix

public class MyEntity {
    private Date date;
    // getters and setters
}

@RestController
public class MyController {
    @GetMapping("/entity")
    public MyEntity getEntity() {
        MyEntity entity = new MyEntity();
        entity.setDate(new Date());
        return entity;
    }
}

The response will contain the date as a numeric timestamp, e.g., {"date":1678912345678} .