Code ví dụ Spring Boot Non Web (Java Desktop Application)

Trong bài này mình sẽ giới thiệu 3 cách thực hiện tạo project Spring Boot non-web

Cách 1: implements CommandLineRunner

import org.springframework.boot.CommandLineRunner;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;

@SpringBootApplication
public class SpringBootConsoleApplication implements CommandLineRunner{

  public static void main(String[] args) {
    SpringApplication app = new SpringApplication(SpringBootConsoleApplication.class);
    app.run(args);
  }

  @Override
  public void run(String... args) throws Exception {
    // TODO
  }
}

Cách 2: Implements ApplicationRunner

import org.springframework.boot.ApplicationArguments;
import org.springframework.boot.ApplicationRunner;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;

@SpringBootApplication
public class SpringBootApplicationRunner implements ApplicationRunner{

  public static void main(String[] args) {
    SpringApplication app = new SpringApplication(SpringBootApplicationRunner.class);
    app.run(args);
  }

  @Override
  public void run(ApplicationArguments args) throws Exception {
    // TODO
  }
}

Cách 3: Sử dụng ApplicationContext

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.context.ApplicationContext;

@SpringBootApplication
public class SpringBootApplicationContext{

  public static void main(String[] args) {
        ApplicationContext ctx = SpringApplication.run(SpringBootApplicationContext.class, args);
        ctx.getBean(...);
  }

}

Với cách 1 và cách 2

• Thường dùng để truy cập và sử dụng các agurment truyền vào lúc chạy ứng dụng, logic chương trình sẽ được viết trong method run.
• Trong class được đánh dấu @SpringBootApplication ta vẫn có thể sử dụng @Autowired để inject các bean và sử dụng trong method run.

Với cách 3: 

• Mọi logic đều viết trong hàm main nên không thể áp dụng @Autowired trong class @SpringBootApplication mà phải lấy các bean thông qua ApplicationContext

Code ví dụ

Tạo Spring Boot Project

Phần thư viện ta không cần chọn mục nào.

Cấu trúc project

File pom.xml

<?xml version="1.0" encoding="UTF-8"?>
<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>stackjava.com</groupId>
  <artifactId>SpringBootNonWeb</artifactId>
  <version>0.0.1-SNAPSHOT</version>
  <packaging>jar</packaging>

  <name>SpringBootNonWeb</name>
  <description>Demo Spring Boot Non-Web</description>

  <parent>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-parent</artifactId>
    <version>2.0.2.RELEASE</version>
    <relativePath/> <!-- lookup parent from repository -->
  </parent>

  <properties>
    <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
    <project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding>
    <java.version>1.8</java.version>
  </properties>

  <dependencies>
    <dependency>
      <groupId>org.springframework.boot</groupId>
      <artifactId>spring-boot-starter</artifactId>
    </dependency>

    <dependency>
      <groupId>org.springframework.boot</groupId>
      <artifactId>spring-boot-starter-test</artifactId>
      <scope>test</scope>
    </dependency>
  </dependencies>

  <build>
    <plugins>
      <plugin>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-maven-plugin</artifactId>
      </plugin>
    </plugins>
  </build>


</project>

Chỉ sử dụng spring-boot-starter

File application.properties

message=Hello World!

File HelloService.java

Đọc message từ file application.properties và in ra qua method hello()

package stackjava.com.sbnonweb.service;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.core.env.Environment;
import org.springframework.stereotype.Service;

@Service
public class HelloService {

  @Autowired
  Environment env;
  
  public void hello() {
    System.out.println(env.getProperty("message"));
  }
}

File SpringBootNonWebApplication.java

Thực hiện chạy ứng dụng

package stackjava.com.sbnonweb;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.CommandLineRunner;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;

import stackjava.com.sbnonweb.service.HelloService;

@SpringBootApplication
public class SpringBootNonWebApplication implements CommandLineRunner{

  @Autowired
  HelloService helloService;
  
  public static void main(String[] args) {
    SpringApplication app = new SpringApplication(SpringBootNonWebApplication.class);
    app.run(args);
  }

  @Override
  public void run(String... args) throws Exception {
    helloService.hello();
  }
}

Trường hợp không dùng CommandLineRunner

package stackjava.com.sbnonweb;

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.context.ApplicationContext;

import stackjava.com.sbnonweb.service.HelloService;

@SpringBootApplication
public class SpringBootNonWebApplication{

  public static void main(String[] args) {
        ApplicationContext ctx = SpringApplication.run(SpringBootNonWebApplication2.class, args);
        HelloService helloService = ctx.getBean(HelloService.class);
        helloService.hello();
  }

}

Kết quả:

Code ví dụ Spring Boot Non Web (Java Desktop Application) stackjava.com

Okay, Done!

Download code ví dụ trên tại đây

 

References:

https://dzone.com/…/applicationrunner-and-commandlinerunne

https://docs.spring.io/…/getting-started-first-application.html