Hi kumar,
you can use json.deserialize() for converting json content into standard object or customobject
deserialize(jsonString, apexType)
Deserializes the specified JSON string into an Apex object of the specified type.
Signature
public static Object deserialize(String jsonString, System.Type apexType)
Parameters
jsonString
Type: String
The JSON content to deserialize.
apexType
Type: System.Type
The Apex type of the object that this method creates after deserializing the JSON content.
Return Value
Type: Object
Usage
If the JSON content contains attributes not present in the System.Type argument, such as a missing field or object, deserialization fails in some circumstances. When deserializing JSON content into a custom object or an sObject using Salesforce API version 34.0 or earlier, this method throws a runtime exception when passed extraneous attributes. When deserializing JSON content into an Apex class in any API version, or into an object in API version 35.0 or later, no exception is thrown. When no exception is thrown, this method ignores extraneous attributes and parses the rest of the JSON content.