json LocalDate

在Java中，将JSON字符串中的日期转换为LocalDate对象可以通过使用Jackson库来实现。下面是两种方法：

方法一：使用@JsonFormat注解

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

public class Main {
    public static void main(String[] args) throws Exception {
        String json = "{\"date\": \"2022-01-01\"}";

        ObjectMapper objectMapper = new ObjectMapper();
        MyObject myObject = objectMapper.readValue(json, MyObject.class);

        System.out.println(myObject.getDate()); // 输出：2022-01-01
    }

    static class MyObject {
        @JsonFormat(pattern = "yyyy-MM-dd")
        private LocalDate date;

        public LocalDate getDate() {
            return date;
        }

        public void setDate(LocalDate date) {
            this.date = date;
        }
    }
}

方法二：自定义反序列化器

import com.fasterxml.jackson.core.JsonParser;
import com.fasterxml.jackson.databind.DeserializationContext;
import com.fasterxml.jackson.databind.JsonDeserializer;
import com.fasterxml.jackson.databind.ObjectMapper;
import com.fasterxml.jackson.databind.module.SimpleModule;

import java.io.IOException;
import java.time.LocalDate;

public class Main {
    public static void main(String[] args) throws Exception {
        String json = "{\"date\": \"2022-01-01\"}";

        ObjectMapper objectMapper = new ObjectMapper();
        SimpleModule module = new SimpleModule();
        module.addDeserializer(LocalDate.class, new LocalDateDeserializer());
        objectMapper.registerModule(module);

        MyObject myObject = objectMapper.readValue(json, MyObject.class);

        System.out.println(myObject.getDate()); // 输出：2022-01-01
    }

    static class MyObject {
        private LocalDate date;

        public LocalDate getDate() {
            return date;
        }

        public void setDate(LocalDate date) {
            this.date = date;
        }
    }

    static class LocalDateDeserializer extends JsonDeserializer<LocalDate> {
        @Override
        public LocalDate deserialize(JsonParser p, DeserializationContext ctxt) throws IOException {
            String dateString = p.getText();
            return LocalDate.parse(dateString);
        }
    }
}