Spring quick start example tutorial

This article illustrates the basic configuration and inversion of control of spring. Share with you for your reference. The details are as follows:

Here we use maven to build Java projects, and the same applies without maven.

1. Create maven project, the project name I created is springdemo.

2. Add dependency package. I added the package through maven, and the configuration of maven is as follows:

<dependency>

    <groupId>org.springframework</groupId>

    <artifactId>spring-context</artifactId>

    <version>4.0.1.RELEASE</version>

</dependency>

<dependency>

    <groupId>org.springframework</groupId>

    <artifactId>spring-core</artifactId>

    <version>4.0.1.RELEASE</version>

</dependency>

Of course, you can also add jar files directly.

3. Create a simple package structure

I created package structures like entity, dao, business, etc.

Write simple code

User, empty code, as follows:

package com.chzhao.model;

public class User {

}

Interface IUserDao

package com.chzhao.dao;

import com.chzhao.model.User;

public interface IUserDao {

     public User findUserById(); 

}

Interface implementation

package com.chzhao.dao;

import com.chzhao.model.User;

public class UserDaoImpl implements IUserDao {

    public User findUserById() {

        System.out.println("dao");

        return null;

    }

}

call

package com.chzhao.springdemo;

import com.chzhao.dao.IUserDao;

import com.chzhao.model.User;

public class UserManager {

    public IUserDao getDao() {

        return dao;

    }

    public void setDao(IUserDao dao) {

        this.dao = dao;

    }

    private IUserDao dao;  

    public User findUser() {  

        return dao.findUserById();  

    }  

}

The main initialization

package com.chzhao.springdemo;

import org.springframework.context.ApplicationContext;

import org.springframework.context.support.ClassPathXmlApplicationContext;
public class App {

    public static void main(String[] args) {
        ApplicationContext act = new ClassPathXmlApplicationContext(

                "applicationContext.xml");

        UserManager um = (UserManager) act.getBean("userManager");

        um.findUser();

    }

}

The corresponding configuration file

<?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">
    <bean id="UserDaoImpl"  class="com.chzhao.dao.UserDaoImpl"/>  

    <bean  name="userManager" class="com.chzhao.springdemo.UserManager">  

        <property name="dao" >  

            <ref bean="UserDaoImpl"/>  

        </property>  

    </bean>  

</beans>

That's the normal way.

Here's how.

First, the configuration file needs to be changed, as shown below

<?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">

    <bean class="org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor" />  

    <bean id="UserDaoImpl"  class="com.chzhao.dao.UserDaoImpl"/>  

    <bean  name="userManager" class="com.chzhao.springdemo.UserManager"> </bean>  

</beans>

Interface implementation

package com.chzhao.dao;

import org.springframework.stereotype.Repository;

import com.chzhao.model.User;

@Repository

public class UserDaoImpl implements IUserDao {

    public User findUserById() {

        System.out.println("dao");

        return null;

    }

}

call

package com.chzhao.springdemo;

import org.springframework.beans.factory.annotation.Autowired;

import com.chzhao.dao.IUserDao;

import com.chzhao.model.User;

public class UserManager {
    @Autowired

    private IUserDao dao;  

    public User findUser() {  

        return dao.findUserById();  

    }  

}

The two methods implement the same thing.

I hope this article has been helpful to your Java programming.