在fastjson 1.2.16版本之后，JSONField支持新的定制化配置serializeUsing，可以单独对某个类的某个属性定制序列化、反序列化。

1.序列化、反序列化接口支持

• 序列化接口

package com.alibaba.fastjson.serializer;

import java.io.IOException;
import java.lang.reflect.Type;

public interface ObjectSerializer {
    void write(JSONSerializer var1, Object var2, Object var3, Type var4, int var5) throws IOException;
}

• 反序列化接口

package com.alibaba.fastjson.parser.deserializer;

import com.alibaba.fastjson.parser.DefaultJSONParser;
import java.lang.reflect.Type;

public interface ObjectDeserializer {
    <T> T deserialze(DefaultJSONParser var1, Type var2, Object var3);

    int getFastMatchToken();
}

2.自定义序列化

@Data
public class User {

    @JSONField(serializeUsing = ModelValueSerializer.class)
    public int age;

}

实现ObjectSerializer接口，重写write方法，自定义序列化。

public class ModelValueSerializer implements ObjectSerializer {
    @Override
    public void write(JSONSerializer serializer, Object object, Object fieldName, Type fieldType, int features) throws IOException {
        Integer value = (Integer) object;
        String text = value + "岁";
        serializer.write(text);
    }
}

测试

    @Test
    void objectSerializerTest() {
        User model = new User();
        model.setAge(10);
        String s = JSON.toJSONString(model);
        System.out.println(s);
    }

输出

{"age":"10岁"}

3.自定义反序列化

@Data
public class User {

    @JSONField(deserializeUsing = ModelValueDeserializer.class)
    private Date birthday;

}

实现ObjectDeserializer接口，重写deserialze方法，自定义反序列化

public class ModelValueDeserializer implements ObjectDeserializer {

    @Override
    public Date deserialze(DefaultJSONParser parser, Type type, Object fieldName) {
        JSONLexer lexer = parser.getLexer();
        String timestamp = lexer.stringVal();
        Long longObject = Long.valueOf(timestamp);
        Date date = new Date(longObject*1000);
        return date;
    }

    @Override
    public int getFastMatchToken() {
        return 0;
    }

}

测试

   @Test
    void objectDeserializerTest() {
        String json = "{\"birthday\":\"1630656260\"}";
        User t = JSON.parseObject(json, User.class);
        System.out.println(t);
    }

输出

User(birthday =Fri Sep 03 16:04:20 CST 2021)