[Java Sprint] Spring XML Configuration : Constructor Injection Demo

Posted 2020-12-30 answer1215

Previous we see how to do Setter injection: https://www.cnblogs.com/Answer1215/p/9472117.html

 

Now let‘s see how to cover setter injection to coustructor injection. Notice, don‘t need to compare which one is better, you can use both.

 

Different from setter injection which use ‘name‘, constructor injection using ‘index‘.

applicationContext.xml

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
       xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
       xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd">

    <!-- Define a class, using implementation-->
    <bean name="foo" class="com.pluralsight.repository.HibernateCustomerRepositoryImpl"></bean>


    <!-- Setter injection: Inject HibernateCustomerRepositoryImpl to customerRepository -->
    <bean name="customerService" class="com.pluralsight.service.CustomerServiceImpl">
        <!--<property name="customerRepository" ref="foo"></property>-->
        <constructor-arg index="0" ref="foo"></constructor-arg>
    </bean>
</beans>

 

package com.pluralsight.service;

import com.pluralsight.model.Customer;
import com.pluralsight.repository.CustomerRepository;

import java.util.List;

public class CustomerServiceImpl implements CustomerService {


    //private CustomerRepository customerRepository = new HibernateCustomerRepositoryImpl();
    private CustomerRepository customerRepository;

    public CustomerServiceImpl () {

    }

    public CustomerServiceImpl (CustomerRepository customerRepository) {
        this.customerRepository = customerRepository;
    }
/*
    public void setCustomerRepository(CustomerRepository customerRepository) {
        this.customerRepository = customerRepository;
    }
*/

    @Override
    public List<Customer> findAll() {
        return customerRepository.findAll();
    }

}