关于开发中时间日期格式问题统一处理方式

直接接收前端String类型日期格式报错 

首先在实际开发中处理日期时间格式时不可避免的事情，最常见的场景见于接口层，如下面所示

@Data
public class CmsTopicComment implements Serializable {
    private Long id;

    private String memberNickName;

    private Long topicId;

    private String memberIcon;

    private String content;

    private Date createTime;

    private Integer showStatus;

}

上面CmsTopicComment类中字段createTime是Date时间格式，如果我们写一个Controller层

     @GetMapping("/test")
    public CommonResponse test(CmsTopicComment cmsTopicComment){
        log.info("接收参数:{}",cmsTopicComment);
        log.info("接收日期：{}",cmsTopicComment.getCreateTime());
        SimpleDateFormat format = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
        log.info("日期格式转换：{}",format.format(cmsTopicComment.getCreateTime()));
        return CommonResponse.success(cmsTopicComment);
    }

 通过APiPost去调用接口

http://localhost:8089/topic/test

{

    "createTime":"2020-10-20 10:20:20"

}

请求参数解析时会报错：

{

    "success": false,

    "code": "402",

    "msg": "请求参数异常",

    "data": "JSON parse error: Cannot deserialize value of type `java.util.Date` from String \"2020-10-20 10:20:20.6666\": not a valid representation (error: Failed to parse Date value '2020-10-20 10:20:20.6666': Cannot parse date \"2020-10-20 10:20:20.6666\": while it seems to fit format 'yyyy-MM-dd'T'HH:mm:ss.SSSX', parsing fails (leniency? null)); nested exception is com.fasterxml.jackson.databind.exc.InvalidFormatException: Cannot deserialize value of type `java.util.Date` from String \"2020-10-20 10:20:20.6666\": not a valid representation (error: Failed to parse Date value '2020-10-20 10:20:20.6666': Cannot parse date \"2020-10-20 10:20:20.6666\": while it seems to fit format 'yyyy-MM-dd'T'HH:mm:ss.SSSX', parsing fails (leniency? null))\n at [Source: (PushbackInputStream); line: 1, column: 34] (through reference chain: com.fairy.test.model.CmsTopicComment[\"createTime\"])"

}

因为字符串 无法去解析成时间日期格式所以直接报错

如果想要接收前端时间请求日期格式，需要了解这两个注解

入参格式化@DateTimeFormat

这个注解式Spring自带的可以直接使用

@DateTimeFormat(pattern = "yyyy-MM-dd HH:mm:ss")
private Date createTime;

重启服务，再次请求 依然是提示异常

{

    "success": false,

    "code": "402",

    "msg": "请求参数异常",

    "data": "JSON parse error: Cannot deserialize value of type `java.util.Date` from String \"2020-10-10 12:20:20\": not a valid representation (error: Failed to parse Date value '2020-10-10 12:20:20': Cannot parse date \"2020-10-10 12:20:20\": while it seems to fit format 'yyyy-MM-dd'T'HH:mm:ss.SSSX', parsing fails (leniency? null)); nested exception is com.fasterxml.jackson.databind.exc.InvalidFormatException: Cannot deserialize value of type `java.util.Date` from String \"2020-10-10 12:20:20\": not a valid representation (error: Failed to parse Date value '2020-10-10 12:20:20': Cannot parse date \"2020-10-10 12:20:20\": while it seems to fit format 'yyyy-MM-dd'T'HH:mm:ss.SSSX', parsing fails (leniency? null))\n at [Source: (PushbackInputStream); line: 1, column: 15] (through reference chain: com.fairy.test.model.CmsTopicComment[\"createTime\"])"

}

@JsonFormat

@JsonFormat(locale="zh", timezone="GMT+8", pattern="yyyy-MM-dd HH:mm:ss")
private Date createTime;

注意：HH 是24小时 hh是12小时制

 再次尝试

可以看到接收参数可以了，并且将时间字符串转换为日期格式，接下来看输出打印信息

2022-05-06 13:11:51.459  INFO 25640 --- [nio-8089-exec-1] c.fairy.test.controller.TopicController  : 接收参数:com.fairy.test.model.CmsTopicComment@4d60cc5c
2022-05-06 13:11:51.861  INFO 25640 --- [nio-8089-exec-1] c.fairy.test.controller.TopicController  : 接收日期：Sat Oct 10 12:20:20 CST 2020
2022-05-06 13:11:52.614  INFO 25640 --- [nio-8089-exec-1] c.fairy.test.controller.TopicController  : 日期格式转换：2020-10-10 12:20:20

再次查看接口调用输出结果

{

    "success": true,

    "code": "200",

    "msg": "操作成功",

    "data": {

        "createTime": "2020-10-10 12:20:20"

    }

}

 可以看到设置@JsonFormat(locale="zh", timezone="GMT+8", pattern="yyyy-MM-dd HH:mm:ss")

后，可以接收时间字符串格式为yyyy-MM-dd HH:mm:ss，并会将Date日期返回结果也是输出为yyyy-MM-dd HH:mm:ss格式

使用@JsonSerialize 和 @JsonDeserialize

@JsonSerialize(using = CustomerJsonSerializer.class)//序列化 将时间日期输出格式化字符串
@JsonDeserialize(using = CustomerJsonDeserializer.class) //反序列化 接收参数
private Date createTime;

public class CustomerJsonDeserializer extends JsonDeserializer<Date> {

    @SneakyThrows
    @Override
    public Date deserialize(JsonParser jsonParser, DeserializationContext deserializationContext) throws IOException {
        SimpleDateFormat format = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
        String date = jsonParser.getText();
        return format.parse(date);
    }
}

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

测试

{

    "success": true,

    "code": "200",

    "msg": "操作成功",

    "data": {

        "createTime": "2020/10/10 12/20/20"

    }

}