Spring Boot项目搭建详解：从零开始到实践应用

2024-11-30 来源：个人技术集锦

Spring Boot项目搭建详解：从零开始到实践应用

引言

Spring Boot作为Spring生态系统的一部分，极大地简化了Spring应用的开发和部署过程。通过自动配置和嵌入式服务器，开发者可以快速构建独立运行的Spring应用。本文将详细介绍如何从零开始搭建一个Spring Boot项目，涵盖项目创建、基本配置、常见功能实现及最佳实践。

1. 创建Spring Boot项目

使用Spring Initializr

Spring Initializr是Spring官方提供的项目生成工具，可以快速创建Spring Boot项目。

导入IDE

将生成的项目导入到IntelliJ IDEA或其他IDE中，确保项目可以成功构建和运行。

2. 配置项目

配置数据库连接

在src/main/resources/application.properties中配置数据库连接信息：

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

spring.jpa.hibernate.ddl-auto=update
spring.jpa.show-sql=true
spring.jpa.properties.hibernate.dialect=org.hibernate.dialect.MySQL5Dialect

创建数据库表

在数据库中创建一个名为demo的数据库，并创建一个User表：

CREATE TABLE `user` (
  `id` BIGINT NOT NULL AUTO_INCREMENT,
  `name` VARCHAR(255) NOT NULL,
  `email` VARCHAR(255) NOT NULL,
  PRIMARY KEY (`id`)
);

3. 实现基本功能

创建实体类

package com.example.demo.entity;

import lombok.Data;

import javax.persistence.Entity;
import javax.persistence.GeneratedValue;
import javax.persistence.GenerationType;
import javax.persistence.Id;

@Data
@Entity
public class User {
    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    private Long id;
    private String name;
    private String email;
}

创建Repository接口

package com.example.demo.repository;

import com.example.demo.entity.User;
import org.springframework.data.jpa.repository.JpaRepository;
import org.springframework.stereotype.Repository;

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

创建Service类

package com.example.demo.service;

import com.example.demo.entity.User;
import com.example.demo.repository.UserRepository;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;

import java.util.List;
import java.util.Optional;

@Service
public class UserService {
    
    @Autowired
    private UserRepository userRepository;

    public List<User> getAllUsers() {
        return userRepository.findAll();
    }

    public Optional<User> getUserById(Long id) {
        return userRepository.findById(id);
    }

    public User saveUser(User user) {
        return userRepository.save(user);
    }

    public void deleteUser(Long id) {
        userRepository.deleteById(id);
    }
}

创建Controller类

package com.example.demo.controller;

import com.example.demo.entity.User;
import com.example.demo.service.UserService;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.http.ResponseEntity;
import org.springframework.web.bind.annotation.*;

import java.util.List;

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

    @Autowired
    private UserService userService;

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

    @GetMapping("/{id}")
    public ResponseEntity<User> getUserById(@PathVariable Long id) {
        return userService.getUserById(id)
                .map(ResponseEntity::ok)
                .orElse(ResponseEntity.notFound().build());
    }

    @PostMapping
    public User createUser(@RequestBody User user) {
        return userService.saveUser(user);
    }

    @DeleteMapping("/{id}")
    public ResponseEntity<Void> deleteUser(@PathVariable Long id) {
        userService.deleteUser(id);
        return ResponseEntity.noContent().build();
    }
}

测试应用

启动Spring Boot应用，在浏览器或Postman中访问以下API端点进行测试：

GET /users：获取所有用户
GET /users/{id}：根据ID获取用户
POST /users：创建新用户
DELETE /users/{id}：删除用户

4. 常见功能实现

全局异常处理

package com.example.demo.exception;

import org.springframework.http.HttpStatus;
import org.springframework.http.ResponseEntity;
import org.springframework.web.bind.annotation.ControllerAdvice;
import org.springframework.web.bind.annotation.ExceptionHandler;
import org.springframework.web.context.request.WebRequest;

@ControllerAdvice
public class GlobalExceptionHandler {

    @ExceptionHandler(Exception.class)
    public ResponseEntity<?> handleGlobalException(Exception ex, WebRequest request) {
        return new ResponseEntity<>(ex.getMessage(), HttpStatus.INTERNAL_SERVER_ERROR);
    }

    @ExceptionHandler(ResourceNotFoundException.class)
    public ResponseEntity<?> handleResourceNotFoundException(ResourceNotFoundException ex, WebRequest request) {
        return new ResponseEntity<>(ex.getMessage(), HttpStatus.NOT_FOUND);
    }
}

分页和排序

在UserService中添加分页和排序功能：

package com.example.demo.service;

import com.example.demo.entity.User;
import com.example.demo.repository.UserRepository;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.data.domain.Page;
import org.springframework.data.domain.PageRequest;
import org.springframework.data.domain.Pageable;
import org.springframework.data.domain.Sort;
import org.springframework.stereotype.Service;

import java.util.List;
import java.util.Optional;

@Service
public class UserService {

    @Autowired
    private UserRepository userRepository;

    public List<User> getAllUsers() {
        return userRepository.findAll();
    }

    public Page<User> getUsersWithPagination(int page, int size) {
        Pageable pageable = PageRequest.of(page, size);
        return userRepository.findAll(pageable);
    }

    public List<User> getUsersWithSorting(String field) {
        return userRepository.findAll(Sort.by(Sort.Direction.ASC, field));
    }

    public Optional<User> getUserById(Long id) {
        return userRepository.findById(id);
    }

    public User saveUser(User user) {
        return userRepository.save(user);
    }

    public void deleteUser(Long id) {
        userRepository.deleteById(id);
    }
}

在UserController中添加分页和排序端点：

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

    @Autowired
    private UserService userService;

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

    @GetMapping("/page")
    public Page<User> getUsersWithPagination(@RequestParam int page, @RequestParam int size) {
        return userService.getUsersWithPagination(page, size);
    }

    @GetMapping("/sort")
    public List<User> getUsersWithSorting(@RequestParam String field) {
        return userService.getUsersWithSorting(field);
    }

    @GetMapping("/{id}")
    public ResponseEntity<User> getUserById(@PathVariable Long id) {
        return userService.getUserById(id)
                .map(ResponseEntity::ok)
                .orElse(ResponseEntity.notFound().build());
    }

    @PostMapping
    public User createUser(@RequestBody User user) {
        return userService.saveUser(user);
    }

    @DeleteMapping("/{id}")
    public ResponseEntity<Void> deleteUser(@PathVariable Long id) {
        userService.deleteUser(id);
        return ResponseEntity.noContent().build();
    }
}

使用Swagger生成API文档

添加Swagger依赖：

<dependency>
    <groupId>io.springfox</groupId>
    <artifactId>springfox-boot-starter</artifactId>
    <version>3.0.0</version>
</dependency>

配置Swagger：

package com.example.demo.config;

import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import springfox.documentation.builders.PathSelectors;
import springfox.documentation.builders.RequestHandlerSelectors;
import springfox.documentation.spi.DocumentationType;


import springfox.documentation.spring.web.plugins.Docket;
import springfox.documentation.swagger2.annotations.EnableSwagger2;

@Configuration
@EnableSwagger2
public class SwaggerConfig {

    @Bean
    public Docket api() {
        return new Docket(DocumentationType.SWAGGER_2)
                .select()
                .apis(RequestHandlerSelectors.basePackage("com.example.demo"))
                .paths(PathSelectors.any())
                .build();
    }
}

启动应用，访问http://localhost:8080/swagger-ui/查看API文档。

5. 最佳实践

配置管理

使用application.properties或application.yml进行配置管理，区分不同环境的配置。

spring:
  profiles:
    active: dev

---

spring:
  profiles: dev
  datasource:
    url: jdbc:mysql://localhost:3306/demo_dev
    username: root
    password: root

---

spring:
  profiles: prod
  datasource:
    url: jdbc:mysql://localhost:3306/demo_prod
    username: prod_user
    password: prod_pass

日志管理

使用SLF4J和Logback进行日志管理，配置日志级别和输出格式。

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

<configuration>
    <appender name="STDOUT" class="ch.qos.logback.core.ConsoleAppender">
        <encoder>
            <pattern>%d{yyyy-MM-dd HH:mm:ss} - %msg%n</pattern>
        </encoder>
    </appender>

    <root level="info">
        <appender-ref ref="STDOUT" />
    </root>

    <logger name="com.example.demo" level="debug" />
</configuration>

安全性

使用Spring Security保护应用，配置身份认证和授权。

添加Spring Security依赖：

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

配置Spring Security：

package com.example.demo.config;

import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.security.config.annotation.web.builders.HttpSecurity;
import org.springframework.security.config.annotation.web.configuration.EnableWebSecurity;
import org.springframework.security.config.annotation.web.configuration.WebSecurityConfigurerAdapter;
import org.springframework.security.crypto.bcrypt.BCryptPasswordEncoder;
import org.springframework.security.crypto.password.PasswordEncoder;

@Configuration
@EnableWebSecurity
public class SecurityConfig extends WebSecurityConfigurerAdapter {

    @Override
    protected void configure(HttpSecurity http) throws Exception {
        http
            .authorizeRequests()
            .antMatchers("/public/**").permitAll()
            .anyRequest().authenticated()
            .and()
            .formLogin().permitAll()
            .and()
            .logout().permitAll();
    }

    @Bean
    public PasswordEncoder passwordEncoder() {
        return new BCryptPasswordEncoder();
    }
}

结语

通过本文的讲解，你应该已经掌握了从零开始搭建Spring Boot项目的全过程，涵盖了项目创建、基本配置、常见功能实现及最佳实践。希望这篇文章能帮助你在实际开发中更高效地构建Spring Boot应用。如果你喜欢这篇文章，请分享给更多的Java开发者，并关注我们的Spring Boot专题，获取更多精彩内容和最新资讯！

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