springboot 使用@JsonComponent自定义JSON序列化程序和反序列化程序

如果使用Jackson对JSON数据进行序列化和反序列化，则可能需要编写自己的 JsonSerializer 和 JsonDeserializer 。自定义序列化程序通常通过模块向Jackson注册，但Spring Boot提供了一个可选的@JsonComponent注释，使直接注册SpringBean更加容易。

您可以直接在 JsonSerializer 或 JsonDeserializer 实现上使用 @JsonComponent注释，注释允许我们将带注释的类公开为Jackson序列化器和/或反序列化器，而无需手动将其添加到ObjectMapper。您还可以在包含序列化程序/反序列化程序作为内部类的类上使用它

package com.example.demo.config;

import java.io.IOException;
import java.time.Instant;
import java.time.LocalDate;
import java.time.LocalDateTime;
import java.time.LocalTime;
import java.time.ZoneOffset;

import com.fasterxml.jackson.core.JsonGenerator;
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 com.fasterxml.jackson.databind.JsonSerializer;
import com.fasterxml.jackson.databind.SerializerProvider;

import org.springframework.boot.jackson.JsonComponent;
/**
 * @author lwb516
 * 
 */
@JsonComponent
public class Java8Date2TimestampJsonComponent {

    /**
     * 当前时区偏移量
     */
    private static final ZoneOffset CURRENT_ZONE_OFFSET = ZoneOffset.ofHours(8);
    /**
     * LocalDate 序列化
     */
    public static class LocalDateSerializer extends JsonSerializer<LocalDate> {
    
        @Override
        public void serialize(LocalDate localDate, JsonGenerator jsonGenerator, SerializerProvider serializerProvider) throws IOException {
            jsonGenerator.writeNumber(localDate.atStartOfDay(CURRENT_ZONE_OFFSET).toInstant().toEpochMilli());
        }
    }
    
    /**
     * LocalDate 反序列化
     */
    public static class LocalDateDeserializer extends JsonDeserializer<LocalDate> {
        @Override
        public LocalDate deserialize(JsonParser jsonParser, DeserializationContext deserializationContext) throws IOException, JsonProcessingException {
            return Instant.ofEpochMilli(Long.valueOf(jsonParser.getText())).atZone(CURRENT_ZONE_OFFSET).toLocalDate();
        }
    }
    private static LocalDate actualDate = Instant.ofEpochMilli( 0L ) .atOffset(CURRENT_ZONE_OFFSET).toLocalDate();
    /**
     * LocalTime 序列化
     */
    public static class LocalTimeSerializer extends JsonSerializer<LocalTime> {
    
        @Override
        public void serialize(LocalTime localTime, JsonGenerator jsonGenerator, SerializerProvider serializerProvider) throws IOException {
            jsonGenerator.writeNumber(LocalDateTime.of(actualDate,localTime).toInstant(CURRENT_ZONE_OFFSET).toEpochMilli());
        }
    }
    
    
    
    /**
     * LocalTime 反序列化
     */
    public static class LocalTimeDeserializer extends JsonDeserializer<LocalTime> {
        @Override
        public LocalTime deserialize(JsonParser jsonParser, DeserializationContext deserializationContext) throws IOException, JsonProcessingException {
            return Instant.ofEpochMilli(Long.valueOf(jsonParser.getText())).atZone(CURRENT_ZONE_OFFSET).toLocalTime();
        }
    }
    /**
     * LocalDateTime 序列化
     */
    public static class LocalDateTimeSerializer extends JsonSerializer<LocalDateTime> {
    
        @Override
        public void serialize(LocalDateTime localDateTime, JsonGenerator jsonGenerator, SerializerProvider serializerProvider) throws IOException {
            jsonGenerator.writeNumber(localDateTime.toInstant(CURRENT_ZONE_OFFSET).toEpochMilli());
        }
    }
    
    /**
     * 当前时区偏移量
     */
    
    /**
     * LocalTime 反序列化
     */
    public static class LocalDateTimeDeserializer extends JsonDeserializer<LocalDateTime> {
        @Override
        public LocalDateTime deserialize(JsonParser jsonParser, DeserializationContext deserializationContext) throws IOException, JsonProcessingException {
            return Instant.ofEpochMilli(Long.valueOf(jsonParser.getText())).atZone(CURRENT_ZONE_OFFSET).toLocalDateTime();
        }
    }
}

需要注意的是不能再使用ObjectMapper进行注册，否则可能会导致不起作用
pom.xml

<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 https://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>
    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>2.1.8.RELEASE</version>
        <relativePath/> <!-- lookup parent from repository -->
    </parent>
    <groupId>com.example</groupId>
    <artifactId>demo</artifactId>
    <version>0.0.1-SNAPSHOT</version>
    <name>demo</name>
    <description>Demo project for Spring Boot</description>

    <properties>
        <java.version>1.8</java.version>
    </properties>

    <dependencies>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter</artifactId>
        </dependency>

        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-test</artifactId>
            <scope>test</scope>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
            <exclusions>
                <exclusion>
                    <groupId>org.springframework.boot</groupId>
                    <artifactId>spring-boot-starter-logging</artifactId>
                </exclusion>
            </exclusions>
        </dependency>
        <dependency>
            <groupId>org.projectlombok</groupId>
            <artifactId>lombok</artifactId>
            <version>1.18.8</version>
            <scope>provided</scope>
        </dependency>
    </dependencies>

    <build>
        <plugins>
            <plugin>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-maven-plugin</artifactId>
            </plugin>
        </plugins>
    </build>

</project>

package com.example.demo.entity;

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

import lombok.Data;

@Data
public class User {
    private Long id;

    private String name;

    private String code;

    private Long parentId;

    private Date createTime;
    private LocalDate localDate;
    private LocalTime localTime;
    private LocalDateTime localDateTime;
}

Controller

package com.example.demo.controller;

import java.time.LocalDate;
import java.time.LocalDateTime;
import java.time.LocalTime;

import com.example.demo.entity.User;

import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.PostMapping;
import org.springframework.web.bind.annotation.RequestBody;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.ResponseBody;
import org.springframework.web.bind.annotation.RestController;


/**
 * @author lwb516
 * @date 2019-06-18 05:57:44
 * @since jdk 1.8
 */
@RestController
@RequestMapping("user-api/job")
public class JobController {

    /**
     * 
     * @return
     */
   @PostMapping("/updateJob")
    public String updateByPrimaryKeySelective(@RequestBody User user) {
        
        return "result";
    }
    @GetMapping("/getUser")
    @ResponseBody
    public User getJob( ) {
        User u  = new User();
        u.setLocalDate(LocalDate.now());
        u.setLocalTime(LocalTime.now());
        u.setLocalDateTime(LocalDateTime.now());
        u.setCode("dsfasd");
        u.setId(213L);
        return u;
    }
}

getUser 返回

{
    "id": 213,
    "name": null,
    "code": "dsfasd",
    "parentId": null,
    "createTime": null,
    "localDate": 1568217600000,
    "localTime": 30937914,
    "localDateTime": 1568277337914
}

updateJob RequestBody

{"localDate":1561478400000,"createtime":1561615193000,"localDateTime":1561651210300,"name":"12345678","id":12,"localTime":2728988000,,"status":1}

后台打印

user=User(id=12, name=12345678, code=null, parentId=null, createTime=null, localDate=2019-06-26, localTime=22:03:08, localDateTime=2019-06-28T00:00:10.300)