实践Spring Boot

Posted on | In | Visitors

Spring Boot用于快速高效地创建可执行的Spring应用程序，进一步升华了约定优于配置。

快速开始

  1. 继承spring-boot-starter-parent
1
2
3
4
5
<parent>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-parent</artifactId>
    <version>1.5.8.RELEASE</version>
</parent>

spring-boot-starter-parent主要定义pluginManagement、编码和Java版本，同时继承spring-boot-dependencies，spring-boot-dependencies主要定义dependencyManagement、pluginManagement和plugins。

  1. 添加依赖

    例如：spring-boot-starter-web

1
2
3
4
5
6
<dependencies>
    <dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-web</artifactId>
    </dependency>
</dependencies>
  1. 编写Main类
1
2
3
4
5
6
@SpringBootApplication
public class ReadingListApplication {
	public static void main(String[] args) {
		SpringApplication.run(ReadingListApplication.class, args);
	}
}

然后编写业务代码

  1. 运行

  • $ mvn spring-boot:run

  • 直接运行Main类

Spring Initializr

Aliyun Java Initializr

特性

起步依赖（Starter）

通过起步依赖，自动识别并构建环境

自动配置（Auto Configuration）

实践Spring-Boot之EnableAutoConfiguration注解

外部化配置（External Configuration）

集中配置到application.properties，起步依赖利用配置来驱动构建环境

Fat Jar或Executable Jar

如果想打包为可执行的jar（即依赖也打包到jar中），则可以通过spring-boot-maven-plugin实现，添加插件

1
2
3
4
5
6
7
8
<build>
    <plugins>
        <plugin>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-maven-plugin</artifactId>
        </plugin>
    </plugins>
</build>

1
2
3
4
# 打包
$ mvn clean package
# 执行
$ java -jar target/spring-boot-sample-0.0.1-SNAPSHOT.jar

容器部署

1
2
3
4
5
6
public class ReadingListServletInitializer extends SpringBootServletInitializer {
@Override
protected SpringApplicationBuilder configure(SpringApplicationBuilder builder) {
	return builder.sources(Application.class);
	}
}

@SpringBootApplication

有@SpringBootConfiguration（@Configuration）、@EnableAutoConfiguration和@ComponentScan组成。

CommandLineRunner

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
/**
 * Interface used to indicate that a bean should <em>run</em> when it is contained within
 * a {@link SpringApplication}. Multiple {@link CommandLineRunner} beans can be defined
 * within the same application context and can be ordered using the {@link Ordered}
 * interface or {@link Order @Order} annotation.
 * <p>
 * If you need access to {@link ApplicationArguments} instead of the raw String array
 * consider using {@link ApplicationRunner}.
 *
 * @author Dave Syer
 * @since 1.0.0
 * @see ApplicationRunner
 */
@FunctionalInterface
public interface CommandLineRunner {

	/**
	 * Callback used to run the bean.
	 * @param args incoming main method arguments
	 * @throws Exception on error
	 */
	void run(String... args) throws Exception;

}

ApplicationRunner

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
/**
 * Interface used to indicate that a bean should <em>run</em> when it is contained within
 * a {@link SpringApplication}. Multiple {@link ApplicationRunner} beans can be defined
 * within the same application context and can be ordered using the {@link Ordered}
 * interface or {@link Order @Order} annotation.
 *
 * @author Phillip Webb
 * @since 1.3.0
 * @see CommandLineRunner
 */
@FunctionalInterface
public interface ApplicationRunner {

	/**
	 * Callback used to run the bean.
	 * @param args incoming application arguments
	 * @throws Exception on error
	 */
	void run(ApplicationArguments args) throws Exception;

}

QA

InetAddress.getLocalHost().getHostName() took 90037 milliseconds to respond

1
2022-06-20 14:56:33,769 WARN [main] o.s.boot.StartupInfoLogger [StartupInfoLogger.java : 116] InetAddress.getLocalHost().getHostName() took 90037 milliseconds to respond. Please verify your network configuration.