如何用 Jackson 解析 LocalDate

Question

我在通过邮递员将日期作为 json 数据传递时遇到问题。对于带有 @NotNull 注释的强制日期，没问题。另一个日期接受空值。但在更新时，该日期会产生问题。我正在使用 Java 1.8 和 spring boot & MySql DB。请帮忙

以下链接我访问过，但与此不符。 JSON parse error: Can not construct instance of java.time.LocalDate: no String-argument constructor/factory method to deserialize from String value

我也用过

@JsonSerialize(using = LocalDateSerializer.class)
@JsonDeserialize(using = LocalDateDeserializer.class)

但问题依旧。

我的用户体验

public class LeaveApplUx {

    @JsonIgnore
    @Size(max = 5, message = "Employee Code Must Be Within 4 To 5 Character Long Or Blank")
    private final String employeeCode;

    @NotNull(message = "Start Date Empty")
    @JsonFormat(shape = JsonFormat.Shape.STRING, pattern = "dd-MM-yyyy")
    private final LocalDate startDate;

    @JsonIgnore
    @JsonFormat(shape = JsonFormat.Shape.STRING, pattern = "dd-MM-yyyy")
    private final LocalDate rejoinDate;

    public LeaveApplUx(
            @Size(min = 4, max = 5, message = "Employee Code Must Be Within 4 To 5 Character Long Or Blank") 
        @JsonProperty("employeeCode") String employeeCode,
            @NotNull(message = "Start Date Empty") @JsonProperty("startDate") LocalDate startDate,
            @JsonProperty("rejoinDate") LocalDate rejoinDate) {
        this.employeeCode = employeeCode;
        this.startDate = startDate;
        this.rejoinDate = rejoinDate;
    }
//  GETTERS
}

创建时，运行正常

{
    "employeeCode": "B426",
    "startDate": "01-03-2023"
}

输入参数：{"employeeCode":"B426","startDate":{"year":2023,"month":"MARCH","monthValue":3,"dayOfMonth":1,"leapYear":false,"dayOfWeek":"WEDNESDAY","dayOfYear":60,"era":"CE","chronology":{"id":"ISO","calendarType":"iso8601"}},"rejoinDate":null} 记录正确保存在数据库中

但是在更新的时候，会产生错误。

{
    "employeeCode": "B426",
    "startDate": "01-03-2023",
    "rejoinDate": "06-03-2023"
}

JSON parse error: 

Cannot deserialize value of type `java.time.LocalDate` from String "06-03-2023": Failed to deserialize java.time.LocalDate: (java.time.format.DateTimeParseException) Text '06-03-2023' could not be parsed at index 0; nested exception is com.fasterxml.jackson.databind.exc.InvalidFormatException: Cannot deserialize value of type `java.time.LocalDate` from String "06-03-2023": Failed to deserialize java.time.LocalDate: (java.time.format.DateTimeParseException) Text '06-03-2023' could not be parsed at index 0
     at [Source: (PushbackInputStream); line: 14, column: 19] (through reference chain: org.myapp.ux.hr.leave.LeaveApplUx["rejoinDate"])

Answer 1

由于您通过构造函数而不是 setter 设置值，因此您应该将 @JsonFormat(...) 放在构造函数参数上，而不是字段。这应该可以解决它：

public class LeaveApplUx {

    @JsonIgnore
    private final String employeeCode;

    private final LocalDate startDate;

    @JsonIgnore
    private final LocalDate rejoinDate;

    public LeaveApplUx(@JsonProperty("employeeCode") String employeeCode,
                       @JsonProperty("startDate") @JsonFormat(shape = JsonFormat.Shape.STRING, pattern = "dd-MM-yyyy") LocalDate startDate,
                       @JsonProperty("rejoinDate") @JsonFormat(shape = JsonFormat.Shape.STRING, pattern = "dd-MM-yyyy") LocalDate rejoinDate) {
        this.employeeCode = employeeCode;
        this.startDate = startDate;
        this.rejoinDate = rejoinDate;
    }

    //getters
}

如何用 Jackson 解析 LocalDate

How to parse LocalDate with Jackson

java

json

spring-boot