Hướng dẫn lập trình Spring cho người mới bắt đầu

// Đây là một interface
public interface HelloWorld {
     public void sayHello();
}

// Class thi hành interface HelloWorld
public class SpringHelloWorld implements HelloWorld {
    public void sayHello()  {
            System.out.println("Spring say Hello!");
    }
}

// Một class khác thi hành Interface HelloWorld
public class StrutsHelloWorld implements HelloWorld {
    public void sayHello()  {
            System.out.println("Struts say Hello!");
    }
}


// Và một class dịch vụ
public class HelloWorldService {
     
      // Một trường có kiểu HelloWorld
      private HelloWorld helloWorld;
     
      // Cấu tử tạo đối tượng HelloWorldService
      // Nó khởi tạo giá trị cho trường 'helloWorld'
      public HelloWorldService()  {
            this.helloWorld = new StrutsHelloWorld();
      }

}

<project xmlns="http://maven.apache.org/POM/4.0.0"
  xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
  xsi:schemaLocation="http://maven.apache.org/POM/4.0.0
  http://maven.apache.org/xsd/maven-4.0.0.xsd">
  <modelVersion>4.0.0</modelVersion>

  <groupId>org.o7planning</groupId>
  <artifactId>HelloSpringAnnotation</artifactId>
  <version>0.0.1-SNAPSHOT</version>
  <packaging>jar</packaging>

  <name>HelloSpringAnnotation</name>
  <url>http://maven.apache.org</url>

  <properties>
    <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
  </properties>

    <dependencies>

        <dependency>
            <groupId>junit</groupId>
            <artifactId>junit</artifactId>
            <version>3.8.1</version>
            <scope>test</scope>
        </dependency>

        <!-- Spring Core -->
        <!-- http://mvnrepository.com/artifact/org.springframework/spring-core -->
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-core</artifactId>
            <version>4.1.4.RELEASE</version>
        </dependency>

        <!-- Spring Context -->
        <!-- http://mvnrepository.com/artifact/org.springframework/spring-context -->
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-context</artifactId>
            <version>4.1.4.RELEASE</version>
        </dependency>

    </dependencies>
 
</project>

package org.o7planning.spring.lang;

// A Language
// Một ngôn ngữ
public interface Language {

    // Get a greeting
    // Một lời chào
    public String getGreeting();

    // Get a bye
    // Một lời tạm biệt
    public String getBye();

}

package org.o7planning.spring.lang.impl;

import org.o7planning.spring.lang.Language;

// Tiếng anh
public class English  implements Language {

  @Override
  public String getGreeting() {
      return "Hello";
  }

  @Override
  public String getBye() {
      return "Bye bye";
  }
 

}

package org.o7planning.spring.lang.impl;

import org.o7planning.spring.lang.Language;

// Tiếng Việt
public class Vietnamese implements Language {

  @Override
  public String getGreeting() {
      return "Xin Chao";
  }

  @Override
  public String getBye() {
      return "Tam Biet";
  }

}

package org.o7planning.spring.bean;

import org.o7planning.spring.lang.Language;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;

@Service
public class GreetingService {

   @Autowired
   private Language language;

   public GreetingService() {

   }

   public void sayGreeting() {
       
       String greeting = language.getGreeting();

       System.out.println("Greeting: " + greeting);
   }

}

package org.o7planning.spring.bean;

import java.util.Date;

import org.springframework.stereotype.Repository;

@Repository
public class MyRepository {

    public String getAppName() {
        return "Hello Spring App";
    }

    public Date getSystemDateTime() {
        return new Date();
    }
    
    
}

package org.o7planning.spring.bean;

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

@Component
public class MyComponent {
   
    @Autowired
    private MyRepository repository;

    public void showAppInfo() {
        System.out.println("Now is: "+ repository.getSystemDateTime());
        System.out.println("App Name: "+ repository.getAppName());
    }

}

package org.o7planning.spring.config;

import org.o7planning.spring.lang.Language;
import org.o7planning.spring.lang.impl.Vietnamese;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.ComponentScan;
import org.springframework.context.annotation.Configuration;

@Configuration
@ComponentScan({"org.o7planning.spring.bean"})
public class AppConfiguration {

    @Bean(name ="language")
    public Language getLanguage() {

        return new Vietnamese();
    }
     
}

package org.o7planning.spring;

import org.o7planning.spring.bean.GreetingService;
import org.o7planning.spring.bean.MyComponent;
import org.o7planning.spring.config.AppConfiguration;
import org.o7planning.spring.lang.Language;
import org.springframework.context.ApplicationContext;
import org.springframework.context.annotation.AnnotationConfigApplicationContext;

public class MainProgram {

   public static void main(String[] args) {
 
     
       // Tạo ra một đối tượng ApplicationContext bằng cách đọc cấu hỉnh
       // trong class AppConfiguration
       ApplicationContext context = new AnnotationConfigApplicationContext(AppConfiguration.class);

       System.out.println("----------");
       Language language = (Language) context.getBean("language");
     
       System.out.println("Bean Language: "+ language);
       System.out.println("Call language.sayBye(): "+ language.getBye());
     
       System.out.println("----------");
     
       GreetingService service = (GreetingService) context.getBean("greetingService");
 

       service.sayGreeting();
 
       System.out.println("----------");
     
       MyComponent myComponent = (MyComponent) context.getBean("myComponent");
     
       myComponent.showAppInfo();
     
   }
 
}

ApplicationContext context = new AnnotationConfigApplicationContext(AppConfiguration.class);