Java程序开发之Spring Boot快速入门：5分钟搭建RESTful API

一、Spring Boot核心优势速览

1. 传统Spring vs Spring Boot对比

二、5分钟极速开发实战

1. 创建项目（使用Spring Initializr）

1. 访问 start.spring.io
2. 选择配置：
   • Project: Maven
   • Language: Java
   • Spring Boot: 3.0.5
   • Dependencies: Spring Web, DevTools
3. 点击Generate下载项目

2. 编写第一个REST控制器

@RestController  
@RequestMapping("/api")  
public class HelloController {  

    @GetMapping("/hello")  
    public String sayHello(@RequestParam(required = false) String name) {  
        return "Hello, " + (name != null ? name : "Spring Boot");  
    }  

    @PostMapping("/users")  
    public User createUser(@RequestBody User user) {  
        return userService.save(user);  
    }  
}  

// 实体类  
public record User(Long id, String name, String email) {}  

3. 运行与测试

mvn spring-boot:run  
# 访问 http://localhost:8080/api/hello?name=CSDN  

三、自动配置与进阶功能

1. 自动装配原理图解

2. 常用Starter依赖说明

四、数据库集成与REST API增强

1. 添加JPA与H2数据库

<!-- pom.xml -->  
<dependency>  
    <groupId>org.springframework.boot</groupId>  
    <artifactId>spring-boot-starter-data-jpa</artifactId>  
</dependency>  
<dependency>  
    <groupId>com.h2database</groupId>  
    <artifactId>h2</artifactId>  
    <scope>runtime</scope>  
</dependency>  

2. 定义实体与Repository

@Entity  
public class User {  
    @Id  
    @GeneratedValue  
    private Long id;  
    private String name;  
    private String email;  
    // getters/setters  
}  

public interface UserRepository extends JpaRepository<User, Long> {}  

3. 编写CRUD API

@RestController  
@RequestMapping("/api/users")  
public class UserController {  

    private final UserRepository repository;  

    @GetMapping  
    public List<User> getAllUsers() {  
        return repository.findAll();  
    }  

    @GetMapping("/{id}")  
    public User getUserById(@PathVariable Long id) {  
        return repository.findById(id)  
               .orElseThrow(() -> new ResponseStatusException(HttpStatus.NOT_FOUND));  
    }  
}  

五、API文档生成（Swagger集成）

1. 添加OpenAPI依赖

<dependency>  
    <groupId>org.springdoc</groupId>  
    <artifactId>springdoc-openapi-starter-webmvc-ui</artifactId>  
    <version>2.1.0</version>  
</dependency>  

2. 访问文档界面

启动后访问：

• API文档：http://localhost:8080/swagger-ui.html
• OpenAPI定义：http://localhost:8080/v3/api-docs

六、生产级部署与监控

1. 打包与运行

mvn clean package  
java -jar target/demo-0.0.1-SNAPSHOT.jar  

2. 健康检查与监控

# 查看健康状态  
curl http://localhost:8080/actuator/health  

# 查看环境配置  
curl http://localhost:8080/actuator/env  

3. Docker化部署

FROM eclipse-temurin:17-jdk-alpine  
COPY target/demo-0.0.1-SNAPSHOT.jar app.jar  
ENTRYPOINT ["java","-jar","/app.jar"]  

七、常见问题与解决方案

1. 启动失败：端口冲突

# application.properties  
server.port=8081  

2. 依赖冲突

mvn dependency:tree > deps.txt  # 分析依赖树  

3. 热部署失效

# 开启自动重启  
spring.devtools.restart.enabled=true