<input  type="number" placeholder="请输入次品数量" :value="defectiveDefaultValue" @input="_defectiveValue" style="border: 1px solid #caccd9;width: 90%;margin: auto;margin-top: 30rpx;" ></input>

_defectiveValue(e){
				this.defectiveDefaultValue = e.detail.value;
			}

@input="_defectiveValue" 即绑定了 _defectiveValue方法

如果没有_defectiveValue方法，将造成你得defectiveDefaultValue 永远都是默认值