My component is not working in Update

<aura:component implements="force:appHostable,flexipage:availableForAllPageTypes" controller="AccountSearchController">
<aura:attribute name="searchKeyword" type="String" default=""/>
<aura:attribute name="lstOfAccount" type="Account[]"/>
<aura:attribute name="listcontact" type="Contact[]"/>
<aura:attribute name="columns" type="List"/>
<aura:attribute name="isBlank" type="boolean" default="false"/>
<aura:attribute name="recordId" type="String"/>
<aura:attribute name="updatedRecord" type="Object[]" />

<div class="slds-m-around_medium" style="background:#fff">
<lightning:layout>
<lightning:layoutItem padding="around-small">
<lightning:spinner variant="brand" size="medium" aura:id="Id_spinner" class="slds-hide" />
<h1 class="slds-page-header__title slds-truncate slds-align-middle"
title="Enter Account Name">Enter Account Name</h1>
<lightning:input value="{!v.searchKeyword}" required="true" aura:id="searchKeyword"/>
</lightning:layoutItem>
</lightning:layout>

<lightning:layout>
<lightning:layoutItem size="2" padding="around-small">
<lightning:button onclick="{!c.Search}" variant="brand" label="Search" iconName="utility:search"/>
</lightning:layoutItem>
</lightning:layout>
<aura:if isTrue="{!and(v.isBlank, v.lstOfAccount!=NULL)}">
<lightning:card title="Account Records" variant="brand">
<lightning:datatable columns="{! v.columns }" data="{!v.lstOfAccount}"
hideCheckboxColumn="true" keyField="Id" onsave ="{!c.Save}"/>
</lightning:card>
</aura:if>
</div>
</aura:component>
({
Search : function(component, event, helper) {
component.set('v.columns', [
{label: 'Name', fieldName: 'Name', editable:'true', type: 'text'},
{label: 'Phone', fieldName: 'Phone', editable:'true', type: 'Phone'},
{label: 'Industry', fieldName: 'Industry', editable:'true', type: 'text'}]);
var action = component.get("c.fetchAccount");
action.setParams({
"searchKeyWord" : component.get("v.searchKeyword")
});
action.setCallback(this, function(response) {
var state = response.getState();
if (state === "SUCCESS") {
component.set("v.lstOfAccount", response.getReturnValue());
component.set("v.isBlank",true);
if(response.getReturnValue()==null){
var toast = $A.get("e.force:showToast");
toast.setParams({
"type":"Error",
"title":"Error",
"message":"No Account Found",
"duration":1000
});
toast.fire();
}
}
});
$A.enqueueAction(action);
},
Save : function (component,event,helper){
var action=component.get("c.saveAccount");
action.setParams({
"AccListStr":JSON.stringify(component.get("v.lstOfAccount"))
});
action.setCallback(this, function(response) {
var state = response.getState();
if (component.isValid() && state === "SUCCESS") {
component.set("v.lstOfAccount", response.getReturnValue());
alert(response.getReturnValue());
var toast = $A.get("e.force:showToast");
toast.setParams({
"type":"Success",
"title":"Success",
"message":"Account Saved Successfully",
"duration":1000
});
toast.fire();
}
});
$A.enqueueAction(action);
}
})
public class AccountSearchController{

@AuraEnabled
public static List <Account> fetchAccount(String searchKeyWord) {
String searchKey = searchKeyWord +'%';
List <Account> lstOfAccount = [SELECT Id, Name,Phone,Industry FROM Account
WHERE Name LIKE:searchKey];

system.debug('==>'+lstOfAccount);
if(lstOfAccount.size() > 0)
return lstOfAccount;
else return null;
}
@auraEnabled
public static List<Account> saveAccount(String AccListStr){
List<Account> accList = (List<Account>)json.deserialize(AccListStr, List<Account>.class);
update accList;
system.debug('===>accList'+accList);
return accList;
}
}