Gson FastJson Jackson comes out Date LocalDate LocalDateTime date type JSON format string

Gson FastJson Jackson processes Date LocalDate LocalDateTime date type JSON format string

Gson processes Date LocalDate LocalDateTime date type JSON format string

When using the Gson library to serialize and deserialize objects whose properties are Date, LocalDate and LocalDateTime,
You can use annotations to specify how dates are formatted. The Gson library supports the @SerializedName and @JsonAdapter annotations.

1. @SerializedName annotation: used to specify the name of the JSON attribute. You can apply the @SerializedName annotation to the properties of the object to specify the corresponding JSON property name.

2. @JsonAdapter annotation: used to specify a custom JsonAdapter class. You can apply the @JsonAdapter annotation to the properties of the object and specify the corresponding JsonAdapter class to format and de-format the date.

Here is a sample code that demonstrates how to use annotations to format objects whose output properties are Date, LocalDate, and LocalDateTime:

Gson handles Date type

Prepare javabean

package com.lihaozhe.json.gson;

import com.google.gson.annotations.JsonAdapter;
import com.lihaozhe.util.date.DateUtils;
import com.lihaozhe.util.json.gson.DateAdapter;
import com.lihaozhe.util.json.gson.LocalDateAdapter;
import com.lihaozhe.util.json.gson.LocalDateTimeAdapter;
import lombok.*;

import java.time.LocalDate;
import java.time.LocalDateTime;
import java.util.Date;

/**
 * @author Li Haozhe
 * @version 1.0
 * @create 2023/10/19
 */
@Getter
@Setter
@ToString
@NoArgsConstructor
@AllArgsConstructor
public class Emp {<!-- -->
    /**
     * account
     */
    private String account;
    /**
     * password
     */
    private String password;
    /**
     * Name
     */
    private String name;
    /**
     * Gender 1 represents male and 0 represents female
     */
    private int gender;
    /**
     * Entry Time
     */
    @JsonAdapter(DateAdapter.class)
    private Date hiredate;
    /**
     * Date of resignation
     */
    @JsonAdapter(DateAdapter.class)
    private Date turnoverDate;
    
    public Emp(String account, String password, String name, int gender) {<!-- -->
        this.account = account;
        this.password = password;
        this.name = name;
        this.gender = gender;
        this.hiredate = new Date();
    }

}

javabean to json format string

Emp emp = new Emp("admin", "e10adc3949ba59abbe56e057f20f883e", "Li Haozhe", 1);
System.out.println(emp);
Gson gson = new GsonBuilder().setDateFormat("yyyy-MM-dd HH:mm:ss").create();
String json = gson.toJson(emp);
System.out.println(json);

The result is as follows:

Emp(account=admin, password=e10adc3949ba59abbe56e057f20f883e, name=李昊之, gender=1, hiredate=Thu Oct 19 19:10:18 CST 2023, turnoverDate=null,)
{<!-- -->"account":"admin","password":"e10adc3949ba59abbe56e057f20f883e","name":"Li Haozhe","gender":1,"hiredate":"2023-10-19 19: 10:18"}

json format string to javabean

Emp emp = new Emp("admin", "e10adc3949ba59abbe56e057f20f883e", "Li Haozhe", 1);
System.out.println(emp);
Gson gson = new GsonBuilder().setDateFormat("yyyy-MM-dd HH:mm:ss").create();
String json = gson.toJson(emp);
System.out.println(json);
Emp fromJson = gson.fromJson(json, Emp.class);
System.out.println(fromJson);
        

The result is as follows:

Emp(account=admin, password=e10adc3949ba59abbe56e057f20f883e, name=李昊之, gender=1, hiredate=Thu Oct 19 19:10:18 CST 2023, turnoverDate=null)
{<!-- -->"account":"admin","password":"e10adc3949ba59abbe56e057f20f883e","name":"Li Haozhe","gender":1,"hiredate":"2023-10-19 19: 10:18"}
Emp(account=admin, password=e10adc3949ba59abbe56e057f20f883e, name=Li Haozhe, gender=1, hiredate=Thu Oct 19 19:10:18 CST 2023, turnoverDate=null)

Gson annotation processing Date LocalDate LocalDateTime

Prepare DateAdapter

package com.lihaozhe.util.json.gson;

import com.google.gson.*;

import java.lang.reflect.Type;
import java.text.DateFormat;
import java.text.SimpleDateFormat;
import java.util.Date;

/**
 * @author Li Haozhe
 * @version 1.0
 * @create 2023/10/19
 */
public class DateAdapter implements JsonDeserializer<Date>, JsonSerializer<Date> {<!-- -->
    private final DateFormat dateFormat = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");

    @Override
    public JsonElement serialize(Date src, Type typeOfSrc, JsonSerializationContext context) {<!-- -->
        return new JsonPrimitive(dateFormat.format(src));
    }

    @Override
    public Date deserialize(JsonElement json, Type typeOfT, JsonDeserializationContext context) throws JsonParseException {<!-- -->
        try {<!-- -->
            return dateFormat.parse(json.getAsString());
        } catch (Exception e) {<!-- -->
            throw new JsonParseException(e);
        }
    }
}

Prepare LocalDateAdapter

package com.lihaozhe.util.json.gson;

/**
 * @author Li Haozhe
 * @version 1.0
 * @create 2023/10/19
 */

import com.google.gson.*;

import java.lang.reflect.Type;
import java.time.LocalDate;
import java.time.format.DateTimeFormatter;

public class LocalDateAdapter implements JsonDeserializer<LocalDate>, JsonSerializer<LocalDate> {<!-- -->
    private final DateTimeFormatter dateTimeFormatter = DateTimeFormatter.ofPattern("yyyy-MM-dd");

    @Override
    public JsonElement serialize(LocalDate src, Type typeOfSrc, JsonSerializationContext context) {<!-- -->
        return new JsonPrimitive(dateTimeFormatter.format(src));
    }

    @Override
    public LocalDate deserialize(JsonElement json, Type typeOfT, JsonDeserializationContext context) throws JsonParseException {<!-- -->
        try {<!-- -->
            return LocalDate.parse(json.getAsString(), dateTimeFormatter);
        } catch (Exception e) {<!-- -->
            throw new JsonParseException(e);
        }
    }
}

Prepare LocalDateTimeAdapter

package com.lihaozhe.util.json.gson;

import com.google.gson.*;

import java.lang.reflect.Type;
import java.time.LocalDateTime;
import java.time.format.DateTimeFormatter;

/**
 * @author Li Haozhe
 * @version 1.0
 * @create 2023/10/19
 */
public class LocalDateTimeAdapter implements JsonDeserializer<LocalDateTime>, JsonSerializer<LocalDateTime> {<!-- -->
    private final DateTimeFormatter dateTimeFormatter = DateTimeFormatter.ofPattern("yyyy-MM-dd HH:mm:ss");

    @Override
    public JsonElement serialize(LocalDateTime src, Type typeOfSrc, JsonSerializationContext context) {<!-- -->
        return new JsonPrimitive(dateTimeFormatter.format(src));
    }

    @Override
    public LocalDateTime deserialize(JsonElement json, Type typeOfT, JsonDeserializationContext context) throws JsonParseException {<!-- -->
        try {<!-- -->
            return LocalDateTime.parse(json.getAsString(), dateTimeFormatter);
        } catch (Exception e) {<!-- -->
            throw new JsonParseException(e);
        }
    }
}

Prepare javabean

package com.lihaozhe.json.gson;

import com.google.gson.annotations.JsonAdapter;
import com.lihaozhe.util.date.DateUtils;
import com.lihaozhe.util.json.gson.DateAdapter;
import com.lihaozhe.util.json.gson.LocalDateAdapter;
import com.lihaozhe.util.json.gson.LocalDateTimeAdapter;
import lombok.*;

import java.time.LocalDate;
import java.time.LocalDateTime;
import java.util.Date;

/**
 * @author Li Haozhe
 * @version 1.0
 * @create 2023/10/19
 */
@Getter
@Setter
@ToString
@NoArgsConstructor
@AllArgsConstructor
public class Emp {<!-- -->
    /**
     * account
     */
    private String account;
    /**
     * password
     */
    private String password;
    /**
     * Name
     */
    private String name;
    /**
     * Gender 1 represents male and 0 represents female
     */
    private int gender;

    /**
     * Entry Time
     */
    @JsonAdapter(DateAdapter.class)
    private Date hiredate;
    /**
     * Date of resignation
     */
    @JsonAdapter(DateAdapter.class)
    private Date turnoverDate;
    /**
     * Account registration date
     */
    @JsonAdapter(LocalDateAdapter.class)
    private LocalDate createDate;
    /**
     * Account registration date and time
     */
    @JsonAdapter(LocalDateTimeAdapter.class)
    private LocalDateTime createDateTime;

    public Emp(String account, String password, String name, int gender) {<!-- -->
        this.account = account;
        this.password = password;
        this.name = name;
        this.gender = gender;
        this.hiredate = new Date();
        this.createDate = LocalDate.now();
        this.createDateTime = LocalDateTime.now();
    }
}

javabean to json format string

Emp emp = new Emp("admin", "e10adc3949ba59abbe56e057f20f883e", "Li Haozhe", 1);
System.out.println(emp);
Gson gson = new Gson();
String json = gson.toJson(emp);
System.out.println(json);

The result is as follows:

Emp(account=admin, password=e10adc3949ba59abbe56e057f20f883e, name=Li Haozhe, gender=1, hiredate=Thu Oct 19 19:20:29 CST 2023, turnoverDate=null, createDate=2023-10-19, createDateTime=2023- 10-19T19:20:29.118)
{<!-- -->"account":"admin","password":"e10adc3949ba59abbe56e057f20f883e","name":"Li Haozhe","gender":1,"hiredate":"2023-10-19 19: 20:29","createDate":"2023-10-19","createDateTime":"2023-10-19 19:20:29"}

json format string to javabean

Emp emp = new Emp("admin", "e10adc3949ba59abbe56e057f20f883e", "Li Haozhe", 1);
System.out.println(emp);
Gson gson = new Gson();
String json = gson.toJson(emp);
System.out.println(json);
Emp fromJson = gson.fromJson(json, Emp.class);
System.out.println(fromJson);
        

The result is as follows:

Emp(account=admin, password=e10adc3949ba59abbe56e057f20f883e, name=Li Haozhe, gender=1, hiredate=Thu Oct 19 19:20:29 CST 2023, turnoverDate=null, createDate=2023-10-19, createDateTime=2023- 10-19T19:20:29.118)
{<!-- -->"account":"admin","password":"e10adc3949ba59abbe56e057f20f883e","name":"Li Haozhe","gender":1,"hiredate":"2023-10-19 19: 20:29","createDate":"2023-10-19","createDateTime":"2023-10-19 19:20:29"}
Emp(account=admin, password=e10adc3949ba59abbe56e057f20f883e, name=Li Haozhe, gender=1, hiredate=Thu Oct 19 19:20:29 CST 2023, turnoverDate=null, createDate=2023-10-19, createDateTime=2023-10-19T19 :20:29.118)

In the above code, a DataObject class is defined, which contains properties of type Date, LocalDate and LocalDateTime.

• The Date type attribute uses the @SerializedName annotation, specifying the attribute name as date.
• The LocalDate type attribute uses the @JsonAdapter annotation and specifies the LocalDateAdapter class as the custom JsonAdapter.
• Attributes of type LocalDateTime also use the @JsonAdapter annotation, and specify the LocalDateTimeAdapter class as the custom JsonAdapter.

The LocalDateAdapter and LocalDateTimeAdapter classes respectively inherit com.google.gson.TypeAdapter and rewrite write() and read() method to implement date formatting and de-formatting.

In the write() method, convert the date object to a string and write it to JSON using the JsonWriter.

In the read() method, read the JSON string and convert it into a date object.

Finally, use the Gson object to serialize the DataObject object into a JSON string and print the output.

It should be noted that when using a custom JsonAdapter class, it needs to be registered into the Gson object so that Gson can correctly use them to format and de-format dates.

FastJson handles Date LocalDate LocalDateTime date type JSON format string

When using FastJson for formatted output, you can specify the date formatting method of the attribute by using the @JSONField annotation.

Here is a sample code that demonstrates how to use annotations to format objects whose output properties are Date, LocalDate, and LocalDateTime:

import com.alibaba.fastjson.JSON;
import com.alibaba.fastjson.annotation.JSONField;

import java.time.LocalDate;
import java.time.LocalDateTime;
import java.time.format.DateTimeFormatter;
import java.util.Date;

public class Main {<!-- -->
    public static void main(String[] args) {<!-- -->
        // date object
        DataObject dataObject = new DataObject(new Date(), LocalDate.now(), LocalDateTime.now());

        // Serialize to JSON string
        String json = JSON.toJSONString(dataObject);

        System.out.println("JSON: " + json);
    }

    static class DataObject {<!-- -->
        @JSONField(format = "yyyy-MM-dd HH:mm:ss")
        private Date date;

        @JSONField(format = "yyyy-MM-dd")
        private LocalDate localDate;

        @JSONField(format = "yyyy-MM-dd HH:mm:ss")
        private LocalDateTime localDateTime;

        public DataObject(Date date, LocalDate localDate, LocalDateTime localDateTime) {<!-- -->
            this.date = date;
            this.localDate = localDate;
            this.localDateTime = localDateTime;
        }
    }
}

In the above code, a DataObject class is defined, which contains properties of type Date, LocalDate and LocalDateTime.

• The Date type attribute uses the @JSONField annotation and specifies the date format as yyyy-MM-dd HH:mm:ss.
• The LocalDate type attribute uses the @JSONField annotation and specifies the date format as yyyy-MM-dd.
• The LocalDateTime type attribute uses the @JSONField annotation and specifies the date format as yyyy-MM-dd HH:mm:ss.

By using the @JSONField annotation on the attribute and specifying the format attribute to specify the date format, FastJson will format the date and output it according to the specified format.

Finally, use the JSON.toJSONString() method to serialize the DataObject object into a JSON string and print the output.

Jackson handles Date LocalDate LocalDateTime date type JSON format string

When using Jackson for formatted output, you can specify the date formatting method of the attribute by using the @JsonFormat annotation.

Here is a sample code that demonstrates how to use annotations to format objects whose output properties are Date, LocalDate, and LocalDateTime:

import com.fasterxml.jackson.annotation.JsonFormat;
import com.fasterxml.jackson.databind.ObjectMapper;

import java.io.IOException;
import java.time.LocalDate;
import java.time.LocalDateTime;
import java.time.format.DateTimeFormatter;
import java.util.Date;

public class Main {<!-- -->
    public static void main(String[] args) throws IOException {<!-- -->
        // date object
        DataObject dataObject = new DataObject(new Date(), LocalDate.now(), LocalDateTime.now());

        // Create ObjectMapper object
        ObjectMapper objectMapper = new ObjectMapper();

        // Serialize to JSON string
        String json = objectMapper.writeValueAsString(dataObject);

        System.out.println("JSON: " + json);
    }

    static class DataObject {<!-- -->
        @JsonFormat(shape = JsonFormat.Shape.STRING, pattern = "yyyy-MM-dd HH-mm-ss", locale = "zh", timezone = "GMT + 8")
    @JsonSerialize(using = DateSerializer.class)
    @JsonDeserialize(using = DateDeserializers.DateDeserializer.class)
        private Date date;

        @JsonFormat(shape = JsonFormat.Shape.STRING, pattern = "yyyy-MM-dd", locale = "zh", timezone = "GMT + 8")
    @JsonSerialize(using = LocalDateSerializer.class)
    @JsonDeserialize(using = LocalDateDeserializer.class)
        private LocalDate localDate;

       @JsonFormat(shape = JsonFormat.Shape.STRING, pattern = "yyyy-MM-dd HH-mm-ss", locale = "zh", timezone = "GMT + 8")
    @JsonSerialize(using = DateSerializer.class)
    @JsonDeserialize(using = DateDeserializers.DateDeserializer.class)
        private LocalDateTime localDateTime;

        public DataObject(Date date, LocalDate localDate, LocalDateTime localDateTime) {<!-- -->
            this.date = date;
            this.localDate = localDate;
            this.localDateTime = localDateTime;
        }
    }
}

In the above code, a DataObject class is defined, including attributes of type Date, LocalDate and LocalDateTime.

• The Date type attribute uses the @JsonFormat annotation, and specifies the date format as yyyy-MM-dd HH:mm:ss and the time zone as GMT + 8.
• The LocalDate type attribute uses the @JsonFormat annotation and specifies the date format as yyyy-MM-dd.
• The LocalDateTime type attribute uses the @JsonFormat annotation and specifies the date format as yyyy-MM-dd HH:mm:ss.

By using the @JsonFormat annotation on the attribute and specifying the pattern attribute to specify the date format, Jackson will format the date and output it according to the specified format.

Finally, use the ObjectMapper object to serialize the DataObject object into a JSON string and print the output.