Multiple dynamic parameters to search with Spring Boot, sometimes someparam can be empty - spring

Question

I am working on Angular 2 with a Spring Boot application, and I am passing some search parameters through my UI to SpringBoot RestController where I am using the CrudRepository<User, id> interface for CRUD operations and am using some methods like findByValue(), but in my app I have four search boxes, like
name, age, city, and country.
If I fill only two boxes then I would like to search for that given two parameters like Age=22, City=New York then only those people who lives in New York with age 22 should be as result if I add name also like name=James then it should search with name and age 22 and city New York.
How do I achieve this kind of functionality in my SpringBoot with a Angular 2 app?
Repository Class:
public interface UserRepository extends CrudRepository<User, Integer> {
public List<User> findAll();
public List<User> findByName(String name);
}
My Controller Code:
#CrossOrigin(origins = "http://localhost:4200", maxAge = 3600)
#RequestMapping(value = "/user/list", method=RequestMethod.POST)
public List<User> getRequestedUsers(#RequestBody User userObject) {
return userRepository.findByAllParam();
// I want to write some method here to get data with all or may be 3, 2, or 1 parameters
}

Answer 1

If your controller is simply returning the repository response, you're better off using Spring Data REST:
https://spring.io/guides/gs/accessing-data-rest/
Once setup, you can expose your repository endpoints directly over REST:
#RepositoryRestResource(collectionResourceRel = "users", path = "users")
public interface UserRepository extends PagingAndSortingRepository<User, Long> {
List<User> findByName(#Param("name") String name);
List<User> findByNameAndAge(#Param("name") String name, #Param("age") Integer age)
List<User> findByNameAndAgeAndCity(#Param("name") String name, #Param("age") Integer age, #Param("city") String city);
}
This then takes care of paging, sorting etc also.
You will end up with an API similar to:
curl -i -X POST -H "Content-Type:application/json" -d "{ \"name\" : \"...\", \"age\" : 0, \"city\" : \"...\" }" http://localhost: 4200/users
In terms of searching with optional parameters, you could manage this on the client side in JavaScript. The following solution doesn't scale but should help you get something working:
function hasValue(id) {
return document.getElementById("age").value !== ''
}
function doSearch() {
const nameHasValue = hasValue("name");
const ageHasValue = hasValue("age");
const cityHasValue = hasValue("city");
if (nameHasValue && ageHasValue && cityHasValue) {
// search by name, age and city
} else if (nameHasValue && ageHasValue) {
// search by name and age
} else if (nameHasValue && cityHasValue) {
// search by name and city
} else if (ageHasValue && cityHasValue) {
// search by age and city
} else if (nameHasValue) {
// search by name
} else if (ageHasValue) {
// search by age
} else if (cityHasValue) {
// search by city
}
}

Answer 2

public interface OrdersRepository extends CrudRepository<OrdersModel, Integer> {
List<OrdersModel> findAllByCityLikeAndPartLike(String city, String part);
}
And if you want searching by city = New York and part = any String:
findAllByCityLikeAndPartLike("New York", "%");
Not exactly problem like yours but I think that will be helpful.