@JsonFormat @DataTimeFormat 时间格式入参时间日期转换 Date

拼搏现实的明天。 2024-03-26 19:16 61阅读 0赞

### **省流：用@JsonFormat即可** ###

### 一、时间格式 ###

1.  #### 字符串转Date ####

入参出参dto里，有时候会看到@DateTimeFormat或@JsonFormat，代码如下。

public class XXXdto{
    
        @DateTimeFormat(pattern = "yyyy-MM-dd")
        private Date startDate;
    }
    
    public class XXXdto{
        @JsonFormat(pattern = "yyyy-MM-dd HH:mm:ss", timezone = "GMT+8")
        private Date startDate;
    }

加@DateTimeFormat注解的目的：将字符串的时间转换成Date类型。此注解只能用于form表单请求和get请求。

加@JsonFormat注解的目的：将字符串的时间转换成Date类型。此注解只能用于json请求。在Controller层入参处需要用@RequestBody

补充：**@DataTimeFormat**用于前端传后端，**@JsonFormat**用于后端传前端，这种说法是错误的。**@JsonFormat**前传后、后传前都可以用。

**使用方法：加在时间类型的变量上。**

1.  #### 时间格式不匹配 ####

这是为了入参可以是日期时间格式(年月日时分秒)的值。如 \{"startDate":"2022-01-01 01:02:02"\}。

如果没有加注解@DateTimeFormat，会报错：

Invalid JSON input: 
    Cannot deserialize value of type `java.util.Date` from String "2023-02-01 01:02:03": not a valid representation (error: Failed to parse Date value '2023-02-01 01:02:03': Cannot parse date "2023-02-01 01:02:03": while it seems to fit format 'yyyy-MM-dd'T'HH:mm:ss.SSSZ', parsing fails (leniency? null)); 
    nested exception is com.fasterxml.jackson.databind.exc.InvalidFormatException: 
    Cannot deserialize value of type `java.util.Date` from String "2023-02-01 01:02:03": not a valid representation (error: Failed to parse Date value '2023-02-01 01:02:03': Cannot parse date "2023-02-01 01:02:03": while it seems to fit format 'yyyy-MM-dd'T'HH:mm:ss.SSSZ', parsing fails (leniency? null))

根据报错信息，while it seems to fit format 'yyyy-MM-dd'T'HH:mm:ss.SSSZ'，判断传入的值日期格式有问题。

1.  #### 正确的时间格式 ####

正确时间格式：2023-02-01T00:00:00.000+0800，即前端传参：\{"startDate":"2023-02-01T00:00:00.000+0800"\}。

由于前端通常也是直接使用时间组件生成的值，时间组件生成的就是正确的时间格式，所以通常后端不需要加@DateTimeFormat。

但如果前端传的是自定义的值，例如：2023-01-01 01:01:01，即年月日时分秒，由于这个值不是正确的时间格式，这时候，后端没有加注解就会报错。

在没有注解的年代，会用SimpleDateFormat做转换。代码如下

public class XXXdto{
    
        private String startDate;
    
        public Date getStartDate(){
            return new SimpleDateFormat("yyyy-MM-dd HH:mm:ss").parse(startDate);
        }
    }

但**@DataTimeFormat**不如**@JsonFormat**好用。另，如果值是纯日期，例如2022-01-01，也不需要用注解。

### 二、注解 ###

1.  #### **@JsonFormat** ####

com.fasterxml.jackson.annotation.JsonFormat;

public class XXXdto{
        @JsonFormat(pattern = "yyyy-MM-dd HH:mm:ss", timezone = "GMT+8")
        private Date startDate;
    }

@JsonFormat 默认的时区是 Greenwich Time， 格林威治时间，而我们是在东八区。查到的时间可能会比数据库中的时间少八个小时。所以需要加上timezone="GMT+8"

1.  #### **@DataTimeFormat** ####

org.springframework.format.annotation.DateTimeFormat

public class XXXdto{
        @DateTimeFormat(pattern = "yyyy-MM-dd HH:mm:ss")
        private Date startDate;
    }

1.  #### @JsonFormat 和 @DateTimeFormat 区别 ####

<table style=""> 
 <tbody> 
 <tr> 
 <td style="width:279px;vertical-align:top;height:52px;"></td> 
 <td style="width:225px;vertical-align:top;height:52px;">@JsonFormat</td> 
 <td style="width:217px;vertical-align:top;height:52px;">@DateTimeFormat</td> 
 </tr> 
 <tr> 
 <td style="width:279px;vertical-align:top;height:52px;">转换前端传入后端的时间格式的值</td> 
 <td style="width:225px;vertical-align:top;height:52px;">√</td> 
 <td style="width:217px;vertical-align:top;height:52px;">√</td> 
 </tr> 
 <tr> 
 <td style="width:279px;vertical-align:top;height:52px;">约束后端响应前端的时间类型的值</td> 
 <td style="width:225px;vertical-align:top;height:52px;">√</td> 
 <td style="width:217px;vertical-align:top;height:52px;">×</td> 
 </tr> 
 <tr> 
 <td style="width:279px;vertical-align:top;height:52px;">数据类型(前端提交到后端)</td> 
 <td style="width:225px;vertical-align:top;height:52px;">必须json用@RequestBody</td> 
 <td style="width:217px;vertical-align:top;height:52px;">必须form表单不用@RequestBody</td> 
 </tr> 
 <tr> 
 <td style="width:279px;vertical-align:top;height:52px;">时区</td> 
 <td style="width:225px;vertical-align:top;height:52px;">√</td> 
 <td style="width:217px;vertical-align:top;height:52px;">×响应给前端的时间会比实际时间晚8个小时</td> 
 </tr> 
 </tbody> 
</table>

### **三、补充：** ###

**1.前端传值给后端，后端接收到的都是字符串。**

**2.前端传日期格式的值，如果形如yyyy-MM-dd，即\{"startDate":"2023-01-02"\}，不需要用****@DataTimeFormat**和**@JsonFormat****，框架会帮你转。**

### 四、自测 ###

各种情况测试对比

<table style=""> 
 <tbody> 
 <tr> 
 <td style="width:156px;vertical-align:top;height:52px;"></td> 
 <td style="width:331px;vertical-align:top;height:52px;">无@RequestBody无@DateTimeFormat</td> 
 <td style="width:341px;vertical-align:top;height:52px;">无@RequestBody有@DateTimeFormat</td> 
 </tr> 
 <tr> 
 <td style="width:156px;vertical-align:top;height:52px;">form表单提交</td> 
 <td style="width:331px;vertical-align:top;height:52px;">报错，见报错1。因为传的值是字符串，而后端的变量是Date类型</td> 
 <td style="width:341px;vertical-align:top;height:52px;">时间格式匹配对，则不会报错。例如：2022-01-01匹配错则报错，见报错2。例如：2022-01-01 10:01:01因为注解中模板是"yyyy-MM-dd"，而传的值是年月日时分秒</td> 
 </tr> 
 <tr> 
 <td style="width:156px;vertical-align:top;height:52px;">json提交</td> 
 <td style="width:331px;vertical-align:top;height:52px;">不报错。入参变量startDate的值是null，说明没有赋值操作。意味着没有@RequestBody，json提交后端接收不到值；form表单提交，后端才能接收到值</td> 
 <td style="width:341px;vertical-align:top;height:52px;">不报错。同前面</td> 
 </tr> 
 </tbody> 
</table>

报错1
    Field error in object 'safescoreHomePageQueryParam' on field 'startTime': rejected value [2023-02-01 01:01:01];Failed to convert property value of type 'java.lang.String' to required type 'java.util.Date' for property 'endTime';nested exception is java.lang.IllegalArgumentException

报错2
    nested exception is java.lang.IllegalArgumentException: Invalid format: "2023-02-01 01:01:01" is malformed at " 01:01:01"

使用@RequestBody，form表单提交会报错如下

Content type 'multipart/form-data;boundary=--------------------------590532731747110494187237;charset=UTF-8' not supported

使用@RequestBody，JSON提交，使用@JsonFormat，入参如果写20220101报错如下。

入参2022-01-01 10:01:01不会报错。时分秒写错不会报错

Invalid JSON input: Cannot deserialize value of type `java.util.Date` from String "20220101": expected format "yyyy-MM-dd"; nested exception is com.fasterxml.jackson.databind.exc.InvalidFormatException: Cannot deserialize value of type `java.util.Date` from String "20220101": expected format "yyyy-MM-dd"
     at [Source: (PushbackInputStream); line: 1, column: 14] (through reference chain: com.xxx.dto.xxx.xxxDTO["startTime"])

使用@RequestBody，JSON提交，不使用@JsonFormat，入参2022-01-01 10:01:01报错如下。入参2022-01-01不会报错。

Invalid JSON input: Cannot deserialize value of type `java.util.Date` from String "2022-01-01 10:01:01": not a valid representation (error: Failed to parse Date value '2022-01-01 10:01:01': Cannot parse date "2022-01-01 10:01:01": while it seems to fit format 'yyyy-MM-dd'T'HH:mm:ss.SSSZ', parsing fails (leniency? null)); nested exception is com.fasterxml.jackson.databind.exc.InvalidFormatException: Cannot deserialize value of type `java.util.Date` from String "2022-01-01 10:01:01": not a valid representation (error: Failed to parse Date value '2022-01-01 10:01:01': Cannot parse date "2022-01-01 10:01:01": while it seems to fit format 'yyyy-MM-dd'T'HH:mm:ss.SSSZ', parsing fails (leniency? null))
     at [Source: (PushbackInputStream); line: 1, column: 14] (through reference chain: com.xxx.dto.xxx.xxxDTO["startTime"])

### 参考 ###

[不要在听大坑们@DateTimeFormat 和 @JsonFormat只是前后端传参的区别了\_\*阿莫西林\*的博客-CSDN博客][DateTimeFormat _ _JsonFormat_-CSDN]

[SpringBoot中时间格式化的5种方法！][SpringBoot_5]

=====================分割线=======================

文章到此已经结束，以下是紫薯布丁

public class XXXdto\{

@DateTimeFormat(pattern = "yyyy-MM-dd")

private Date startDate;

public class XXXdto\{

@JsonFormat(pattern = "yyyy-MM-dd HH:mm:ss", timezone = "GMT+8")

private Date startDate;

Invalid JSON input:

Cannot deserialize value of type \`java.util.Date\` from String "2023-02-01 01:02:03": not a valid representation (error: Failed to parse Date value '2023-02-01 01:02:03': Cannot parse date "2023-02-01 01:02:03": while it seems to fit format 'yyyy-MM-dd'T'HH:mm:ss.SSSZ', parsing fails (leniency? null));

nested exception is com.fasterxml.jackson.databind.exc.InvalidFormatException:

public class XXXdto\{

private String startDate;

public Date getStartDate()\{

return new SimpleDateFormat("yyyy-MM-dd HH:mm:ss").parse(startDate);

public class XXXdto\{

@JsonFormat(pattern = "yyyy-MM-dd HH:mm:ss", timezone = "GMT+8")

private Date startDate;

public class XXXdto\{

@DateTimeFormat(pattern = "yyyy-MM-dd HH:mm:ss")

private Date startDate;

报错1

Field error in object 'safescoreHomePageQueryParam' on field 'startTime': rejected value \[2023-02-01 01:01:01\];Failed to convert property value of type 'java.lang.String' to required type 'java.util.Date' for property 'endTime';nested exception is java.lang.IllegalArgumentException

报错2

nested exception is java.lang.IllegalArgumentException: Invalid format: "2023-02-01 01:01:01" is malformed at " 01:01:01"

Content type 'multipart/form-data;boundary=--------------------------590532731747110494187237;charset=UTF-8' not supported

Invalid JSON input: Cannot deserialize value of type \`java.util.Date\` from String "20220101": expected format "yyyy-MM-dd"; nested exception is com.fasterxml.jackson.databind.exc.InvalidFormatException: Cannot deserialize value of type \`java.util.Date\` from String "20220101": expected format "yyyy-MM-dd"

at \[Source: (PushbackInputStream); line: 1, column: 14\] (through reference chain: com.xxx.dto.xxx.xxxDTO\["startTime"\])

Invalid JSON input: Cannot deserialize value of type \`java.util.Date\` from String "2022-01-01 10:01:01": not a valid representation (error: Failed to parse Date value '2022-01-01 10:01:01': Cannot parse date "2022-01-01 10:01:01": while it seems to fit format 'yyyy-MM-dd'T'HH:mm:ss.SSSZ', parsing fails (leniency? null)); nested exception is com.fasterxml.jackson.databind.exc.InvalidFormatException: Cannot deserialize value of type \`java.util.Date\` from String "2022-01-01 10:01:01": not a valid representation (error: Failed to parse Date value '2022-01-01 10:01:01': Cannot parse date "2022-01-01 10:01:01": while it seems to fit format 'yyyy-MM-dd'T'HH:mm:ss.SSSZ', parsing fails (leniency? null))

at \[Source: (PushbackInputStream); line: 1, column: 14\] (through reference chain: com.xxx.dto.xxx.xxxDTO\["startTime"\])

[DateTimeFormat _ _JsonFormat_-CSDN]: https://blog.csdn.net/a1035434631/article/details/109740122
[SpringBoot_5]: https://cloud.tencent.com/developer/article/1853116