SpringBoot @ JsonDeserialize Customize Json Serialization

Directory @ JsonDeserialize Custom Json Serialization 1. Problem 2. Phenomenon 3. Solution @ JsonSerialize and @ JsonDeserialize Use 1. Annotated Use 2. Custom Implementation Class

@ JsonDeserialize Custom Json Serialization

1. Problems

In the project, SpringBoot is used as the framework. When the third-party interface is called, the returned parameter Date type needs to be customized for Json serialization, processed and data accepted

2. Phenomena

Invoke the third-party interface and return a parameter of type Date in the following format:

{
    "created": "2018-12-27 16:15:25",
    "lastupd": "2018-12-27 08:25:48"
}

The format of returned Date type data is: yyyy-MM-dd HH: mm: ss, Json default serialization Date type parameter, format is: yyyy-MM-dd HH: mm: ss. SSS, then user-defined serialization is required

3. Solutions

Create the received data object and generate the Get\ Set method:, on top of the Set method, add the @ JsonDeserialize annotation, as follows:

 public class TestDto implements Serializable {   
    /**
     *  Generation time 
     *
     */
    private Date created;
    /**
     * LastUpd
     *
     */
    private Date lastUpd;
​
    public Date getCreated() {
        return created;
    }
    @JsonDeserialize(using = CustomJsonDateDeserializer.class)
    public void setCreated(Date created) {
        this.created = created;
    }
    public Date getLastUpd() {
        return lastUpd;
    }
    @JsonDeserialize(using = CustomJsonDateDeserializer.class)
    public void setLastUpd(Date lastUpd) {
        this.lastUpd = lastUpd;
    }
 }

When doing custom serialization, add the @ JsonDeserialize (using = CustomJsonDateDeserializer. class) annotation,

Where @ JsonDeserialize means telling SpringBoot that the current attribute is custom serialized, then SpringBoot will skip this parameter when serializing

CustomJsonDateDeserializer. class is a custom serialization object, as follows:

package com.test;​
import com.fasterxml.jackson.core.JsonParser;
import com.fasterxml.jackson.core.JsonProcessingException;
import com.fasterxml.jackson.databind.DeserializationContext;
import com.fasterxml.jackson.databind.JsonDeserializer;
​
import java.io.IOException;
import java.text.ParseException;
import java.text.SimpleDateFormat;
import java.util.Date;
​
/**
 *  Custom serialization 
 **/
public class CustomJsonDateDeserializer extends JsonDeserializer<Date> {
​
    @Override
    public Date deserialize(JsonParser jp, DeserializationContext ctxt) throws IOException, JsonProcessingException {
        SimpleDateFormat format = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
        String date = jp.getText();
        try {
            return format.parse(date);
        } catch (ParseException e) {
            throw new RuntimeException(e);
        }
    }
}

Above, when receiving data, Json serialization will be customized to receive data in Date format.

Using @ JsonSerialize with @ JsonDeserialize

1. Use as an annotation

@JsonDeserialize(using= DateJsonDeserializer.class)
@JsonSerialize(using= DateJsonSerializer.class)
private Date time;

2. Custom implementation classes

public class DateJsonDeserializer extends JsonDeserializer<Date>
{
    public static final SimpleDateFormat format=new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
    @Override
    public Date deserialize(com.fasterxml.jackson.core.JsonParser jsonParser, DeserializationContext deserializationContext) throws IOException, com.fasterxml.jackson.core.JsonProcessingException {
 
        try
        {
            if(jsonParser!=null&&StringUtils.isNotEmpty(jsonParser.getText())){
                return format.parse(jsonParser.getText());
            }else {
                return null;
            }
 
        }
        catch(Exception e)
        {
            System.out.println(e.getMessage());
            throw new RuntimeException(e);
        }
    }
}

public class DateJsonSerializer extends JsonSerializer<Date> {
    public static final SimpleDateFormat format=new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
 
    @Override
    public void serialize(Date date, JsonGenerator jsonGenerator, SerializerProvider serializerProvider) throws IOException {
        jsonGenerator.writeString(format.format(date));
    }