字段有日期类型的，输入2018-8-8插入不进去

Field error in object 'customer' on field 'buyDate': rejected value []; codes [typeMismatch.customer.buyDate,typeMismatch.buyDate,typeMismatch.java.util.Date,typeMismatch]; arguments [org.springframework.context.support.DefaultMessageSourceResolvable: codes [customer.buyDate,buyDate]; arguments []; default message [buyDate]]; default message [Failed to convert property value of type 'java.lang.String' to required type 'java.util.Date' for property 'buyDate'; nested exception is org.springframework.core.convert.ConversionFailedException: Failed to convert from type [java.lang.String] to type [@com.baomidou.mybatisplus.annotations.TableField java.util.Date] for value ''; nested exception is java.lang.IllegalArgumentException]