Introduction to Spring Boot with Code Examples

Spring Boot Overview

Spring Boot, provided by Pivotal, simplifies the creation and development of Spring applications by offering convention‑over‑configuration, embedded containers, and starter dependencies, allowing developers to run a Spring app with a single Java class or an executable JAR.

Key Advantages

Fast onboarding for all Spring developers

Out‑of‑the‑box defaults reduce configuration effort

Embedded servlet container simplifies web projects

No redundant XML or boilerplate code required

Running a Simple Application

Using JDK 8 and an IDE (IDEA, STS, Eclipse) you can create a Maven project and add the Spring Boot parent and starter dependencies.

<!--引入SpringBoot父依赖-->
<parent>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-parent</artifactId>
    <version>2.0.5.RELEASE</version>
    <relativePath/>
</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>

Add the web starter:

<dependencies>
    <!-- SpringBoot‑WEB module -->
    <dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-web</artifactId>
    </dependency>
</dependencies>

Create the main class:

@SpringBootApplication
public class SpringbootFirstExperienceApplication {
    public static void main(String[] args) {
        SpringApplication.run(SpringbootFirstExperienceApplication.class, args);
    }
}

The @SpringBootApplication annotation combines @Configuration, @EnableAutoConfiguration, and @ComponentScan.

Project Directory Structure

Typical resources under src/main/resources include templates (Thymeleaf, FreeMarker, etc.), static (CSS/JS), optional public, and application.properties (or application.yml) for configuration such as port, datasource, etc.

JdbcTemplate Integration

Add the JDBC starter and MySQL driver, then configure the datasource in application.properties:

spring.datasource.url=jdbc:mysql://localhost:3306/mybatis
spring.datasource.username=root
spring.datasource.password=root
spring.datasource.driver-class-name=com.mysql.jdbc.Driver

Write a service using @Service and JdbcTemplate to execute SQL statements.

JPA Integration

Include spring-boot-starter-data-jpa and the MySQL driver, then reuse the same datasource properties. Define an entity class annotated with @Entity and @Table, a repository extending JpaRepository, and a controller to expose CRUD endpoints.

MyBatis Integration

Add mybatis-spring-boot-starter and configure mapper locations and type aliases in application.properties:

mybatis.mapper-locations=classpath:com/simple/springboot/mybatis/dao/mapper/*.xml
mybatis.type-aliases-package=com.simple.springboot.mybatis.entity

Implement mapper interfaces and use them in a service layer.

JSP Integration

Package the project as a WAR, add spring-boot-starter-tomcat and tomcat-embed-jasper dependencies, and set view resolver prefixes/suffixes:

spring.mvc.view.prefix=/WEB-INF/views/
spring.mvc.view.suffix=.jsp

AOP Usage

Define an aspect class with @Aspect and @Component, declare pointcuts, and implement @Before, @After, @AfterThrowing, and @Around advices to intercept methods in the com.simple.springboot.util package.

Task Scheduling

Enable scheduling with @EnableScheduling on the main class, then create a component with a method annotated @Scheduled (fixedRate = 1000) to print the current time every second.

All code examples are available at https://gitlab.com/450255266/code .