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java error（2）保存时间带时分秒，回显时分秒变成00:00:00

article 2025/1/16 7:30:39

超简单，顺带记录一下

1.入参实体类上使用注释：@JsonFormat(pattern = “yyyy-MM-dd”) 导致舍弃了时分秒的部分。
2.数据库字段对应的类型是 date。date就是日期，日期就不带时分秒。
3.返参实体类使用了@JsonFormat(pattern = “yyyy-MM-dd”) 导致舍弃了时分秒部分。

扩展
关于注解@JsonFormat

General-purpose annotation used for configuring details of how values of properties are to be serialized. Unlike most other Jackson annotations, annotation does not have specific universal interpretation: instead, effect depends on datatype of property being annotated (or more specifically, deserializer and serializer being used). <p> Common uses include choosing between alternate representations -- for example, whether {@link java.util.Date} is to be serialized as number (Java timestamp) or String (such as ISO-8601 compatible time value) -- as well as configuring exact details with {@link pattern} property. <p> As of Jackson 2.6, known special handling includes: <ul> <li>{@link java.util.Date}: Shape can be {@link ShapeSTRING} or {@link ShapeNUMBER}; pattern may contain {@link java.text.SimpleDateFormat}-compatible pattern definition. <li> <li>Can be used on Classes (types) as well, for modified default behavior, possibly overridden by per-property annotation <li> <li>{@link java.lang.Enum}s: Shapes {@link ShapeSTRING} and {@link ShapeNUMBER} can be used to change between numeric (index) and textual (name or <code>toString()<code>); but it is also possible to use {@link ShapeOBJECT} to serialize (but not deserialize) {@link java.lang.Enum}s as JSON Objects (as if they were POJOs). NOTE: serialization as JSON Object only works with class annotation; will not work as per-property annotation. <li> <li>{@link java.util.Collection}s can be serialized as (and deserialized from) JSON Objects, if {@link ShapeOBJECT} is used. NOTE: can ONLY be used as class annotation; will not work as per-property annotation. <li> <li>{@link java.lang.Number} subclasses can be serialized as full objects if {@link ShapeOBJECT} is used. Otherwise the default behavior of serializing to a scalar number value will be preferred. NOTE: can ONLY be used as class annotation; will not work as per-property annotation. <li> <ul>

机器翻译：通用注释，用于配置如何序列化属性值的详细信息。与大多数其他 Jackson 注释不同，注释没有特定的通用解释：相反，效果取决于被注释的属性的数据类型（或者更具体地说，使用的反序列化器和序列化器）。<p> 常见用途包括在替代表示形式之间进行选择——例如，{@link java.util.Date} 是序列化为数字（Java 时间戳）还是字符串（例如 ISO-8601 兼容的时间值）——以及使用 {@link pattern} 属性配置确切的详细信息。<p> 从 Jackson 2.6 开始，已知的特殊处理包括： <ul> <li>{@link java.util.Date}：形状可以是 {@link ShapeSTRING} 或 {@link ShapeNUMBER};pattern 可能包含 {@link java.text.SimpleDateFormat} 兼容的模式定义。<li> <li>也可以用于类（类型），用于修改默认行为，可能被每个属性的注释 <li> <li>{@link java.lang.Enum} 覆盖：形状 {@link ShapeSTRING} 和 {@link ShapeNUMBER} 可用于在数字（索引）和文本（name 或 <code>toString（））之间切换<code>;但也可以使用 {@link ShapeOBJECT} 将 {@link java.lang.Enum} 序列化（但不能反序列化）为 JSON 对象（就像它们是 POJO 一样）。注意：序列化为 JSON Object 仅适用于类注释;将不用作每个属性的注释。<li> <li>如果使用 {@link ShapeOBJECT}，则 {@link java.util.Collection} 可以序列化为 JSON 对象（并从中反序列化）。注意：只能用作类注释;将不用作每个属性的注释。<li> <li>如果使用 {@link ShapeOBJECT}，则可以将 {@link java.lang.Number} 子类序列化为完整对象。否则，将首选序列化为标量数值的默认行为。注意：只能用作类注释;将不用作每个属性的注释。<li> <ul>

补充几个 @JsonFormat 的使用方式。

//实体类
@Data
@Accessors(chain = true)
public class TestJsonFormat {
    @JsonFormat(shape = JsonFormat.Shape.NUMBER_INT)
    private Integer sendDate;
    @JsonFormat(shape = JsonFormat.Shape.STRING)
    private String str;
    @JsonFormat(shape = JsonFormat.Shape.NUMBER)
    private Date dateNum;
    @JsonFormat(pattern = "yyyy-MM-dd")
    private Date getDate;
}
//接口定义
    @GetMapping("/testJsonFormat")
    public AjaxResult testJsonFormat(@RequestBody TestJsonFormat format) {
        format.setDateNum(new Date());
        return AjaxResult.success(format);
    }
//接口调用入参：
{
    "sendDate": 12.3,
    "str": 333,
    "receiveDate":"2023-10-21"
}
//打印结果：
TestJsonFormat(sendDate=12, str=333, dateNum=null, receiveDate=Sat Oct 21 00:00:00 CST 2023)
//返回参数：
{
	"msg": "操作成功",
	"code": 200,
	"data": {
		"sendDate": 12,
		"str": "333",
		"dateNum": 1734569603473,
		"receiveDate": "2023-10-21"
	}
}
可以看到：
1、@JsonFormat(shape = JsonFormat.Shape.NUMBER_INT)：将接收数据转换成了整形
2、@JsonFormat(shape = JsonFormat.Shape.STRING)：将接收数据转换成了字符串类型
3、@JsonFormat(shape = JsonFormat.Shape.NUMBER)：将返回的数据转换成了数字类型时间戳
4、@JsonFormat(pattern = "yyyy-MM-dd")：将字符串类型的时间转换成了对象，又以指定格式返回字符串