Spring Boot实现加法API与用户认证登录系统

在Spring框架中，你可以通过创建Spring Boot项目来快速实现加法计算器和用户登录功能。以下是一个简要的步骤指南，帮助你了解如何分别实现这两个功能。

1. 创建Spring Boot项目

首先，你需要创建一个Spring Boot项目。你可以使用Spring Initializr网站（https://start.spring.io/）来生成一个包含所需依赖的项目，或者在你的IDE中创建一个新的Spring Boot项目。

2. 添加依赖

对于加法计算器和用户登录功能，你需要以下依赖：

Spring Web（用于创建RESTful API）
Spring Security（用于用户认证和授权，可选，但推荐用于登录功能）
Spring Data JPA（如果你打算将用户信息存储在数据库中，可选）
H2 Database（一个内存数据库，适合快速原型开发，可选）

3. 实现加法计算器

创建一个简单的REST控制器来处理加法请求。


@RestController  
@RequestMapping("/api/calculator")  
public class CalculatorController {  
  
    @PostMapping("/add")  
    public ResponseEntity<Integer> add(@RequestBody Map<String, Integer> numbers) {  
        Integer num1 = numbers.get("num1");  
        Integer num2 = numbers.get("num2");  
        if (num1 == null || num2 == null) {  
            return ResponseEntity.badRequest().body(null);  
        }  
        int result = num1 + num2;  
        return ResponseEntity.ok(result);  
    }  
}
@RestController  
@RequestMapping("/api/calculator")  
public class CalculatorController {  
  
    @PostMapping("/add")  
    public ResponseEntity<Integer> add(@RequestBody Map<String, Integer> numbers) {  
        Integer num1 = numbers.get("num1");  
        Integer num2 = numbers.get("num2");  
        if (num1 == null || num2 == null) {  
            return ResponseEntity.badRequest().body(null);  
        }  
        int result = num1 + num2;  
        return ResponseEntity.ok(result);  
    }  
}
@RestController  
@RequestMapping("/api/calculator")  
public class CalculatorController {  
  
    @PostMapping("/add")  
    public ResponseEntity<Integer> add(@RequestBody Map<String, Integer> numbers) {  
        Integer num1 = numbers.get("num1");  
        Integer num2 = numbers.get("num2");  
        if (num1 == null || num2 == null) {  
            return ResponseEntity.badRequest().body(null);  
        }  
        int result = num1 + num2;  
        return ResponseEntity.ok(result);  
    }  
}

你可以使用Postman或curl来测试这个API，发送一个POST请求到/api/calculator/add，并在请求体中提供num1和num2参数。

4. 实现用户登录功能

配置Spring Security

创建一个Spring Security配置类。


@EnableWebSecurity  
public class SecurityConfig extends WebSecurityConfigurerAdapter {  
  
    @Autowired  
    private UserDetailsService userDetailsService;  
  
    @Override  
    protected void configure(AuthenticationManagerBuilder auth) throws Exception {  
        auth.userDetailsService(userDetailsService).passwordEncoder(new BCryptPasswordEncoder());  
    }  
  
    @Override  
    protected void configure(HttpSecurity http) throws Exception {  
        http  
            .authorizeRequests()  
                .antMatchers("/api/public/**").permitAll()  
                .anyRequest().authenticated()  
                .and()  
            .formLogin()  
                .permitAll()  
                .and()  
            .logout()  
                .permitAll();  
    }  
  
    @Bean  
    public PasswordEncoder passwordEncoder() {  
        return new BCryptPasswordEncoder();  
    }  
}
@EnableWebSecurity  
public class SecurityConfig extends WebSecurityConfigurerAdapter {  
  
    @Autowired  
    private UserDetailsService userDetailsService;  
  
    @Override  
    protected void configure(AuthenticationManagerBuilder auth) throws Exception {  
        auth.userDetailsService(userDetailsService).passwordEncoder(new BCryptPasswordEncoder());  
    }  
  
    @Override  
    protected void configure(HttpSecurity http) throws Exception {  
        http  
            .authorizeRequests()  
                .antMatchers("/api/public/**").permitAll()  
                .anyRequest().authenticated()  
                .and()  
            .formLogin()  
                .permitAll()  
                .and()  
            .logout()  
                .permitAll();  
    }  
  
    @Bean  
    public PasswordEncoder passwordEncoder() {  
        return new BCryptPasswordEncoder();  
    }  
}
@EnableWebSecurity  
public class SecurityConfig extends WebSecurityConfigurerAdapter {  
  
    @Autowired  
    private UserDetailsService userDetailsService;  
  
    @Override  
    protected void configure(AuthenticationManagerBuilder auth) throws Exception {  
        auth.userDetailsService(userDetailsService).passwordEncoder(new BCryptPasswordEncoder());  
    }  
  
    @Override  
    protected void configure(HttpSecurity http) throws Exception {  
        http  
            .authorizeRequests()  
                .antMatchers("/api/public/**").permitAll()  
                .anyRequest().authenticated()  
                .and()  
            .formLogin()  
                .permitAll()  
                .and()  
            .logout()  
                .permitAll();  
    }  
  
    @Bean  
    public PasswordEncoder passwordEncoder() {  
        return new BCryptPasswordEncoder();  
    }  
}

创建UserDetailsService实现

你需要实现UserDetailsService接口来加载用户特定的数据。


@Service  
public class CustomUserDetailsService implements UserDetailsService {  
  
    @Autowired  
    private UserRepository userRepository;  
  
    @Override  
    public UserDetails loadUserByUsername(String username) throws UsernameNotFoundException {  
        User user = userRepository.findByUsername(username);  
        if (user == null) {  
            throw new UsernameNotFoundException("User not found");  
        }  
        return new org.springframework.security.core.userdetails.User(user.getUsername(), user.getPassword(), new ArrayList<>());  
    }  
}
@Service  
public class CustomUserDetailsService implements UserDetailsService {  
  
    @Autowired  
    private UserRepository userRepository;  
  
    @Override  
    public UserDetails loadUserByUsername(String username) throws UsernameNotFoundException {  
        User user = userRepository.findByUsername(username);  
        if (user == null) {  
            throw new UsernameNotFoundException("User not found");  
        }  
        return new org.springframework.security.core.userdetails.User(user.getUsername(), user.getPassword(), new ArrayList<>());  
    }  
}
@Service  
public class CustomUserDetailsService implements UserDetailsService {  
  
    @Autowired  
    private UserRepository userRepository;  
  
    @Override  
    public UserDetails loadUserByUsername(String username) throws UsernameNotFoundException {  
        User user = userRepository.findByUsername(username);  
        if (user == null) {  
            throw new UsernameNotFoundException("User not found");  
        }  
        return new org.springframework.security.core.userdetails.User(user.getUsername(), user.getPassword(), new ArrayList<>());  
    }  
}

创建用户实体和存储库

定义一个简单的用户实体和一个JPA存储库来管理用户。


@Entity  
public class User {  
  
    @Id  
    @GeneratedValue(strategy = GenerationType.IDENTITY)  
    private Long id;  
  
    private String username;  
    private String password;  
  
    // Getters and Setters  
}  
  
public interface UserRepository extends JpaRepository<User, Long> {  
    User findByUsername(String username);  
}
@Entity  
public class User {  
  
    @Id  
    @GeneratedValue(strategy = GenerationType.IDENTITY)  
    private Long id;  
  
    private String username;  
    private String password;  
  
    // Getters and Setters  
}  
  
public interface UserRepository extends JpaRepository<User, Long> {  
    User findByUsername(String username);  
}
@Entity  
public class User {  
  
    @Id  
    @GeneratedValue(strategy = GenerationType.IDENTITY)  
    private Long id;  
  
    private String username;  
    private String password;  
  
    // Getters and Setters  
}  
  
public interface UserRepository extends JpaRepository<User, Long> {  
    User findByUsername(String username);  
}

初始化一些用户数据

你可以在应用启动时初始化一些用户数据。


@Component  
public class DataLoader implements CommandLineRunner {  
  
    @Autowired  
    private UserRepository userRepository;  
  
    @Autowired  
    private PasswordEncoder passwordEncoder;  
  
    @Override  
    public void run(String... args) throws Exception {  
        User user = new User();  
        user.setUsername("user");  
        user.setPassword(passwordEncoder.encode("password"));  
        userRepository.save(user);  
    }  
}
@Component  
public class DataLoader implements CommandLineRunner {  
  
    @Autowired  
    private UserRepository userRepository;  
  
    @Autowired  
    private PasswordEncoder passwordEncoder;  
  
    @Override  
    public void run(String... args) throws Exception {  
        User user = new User();  
        user.setUsername("user");  
        user.setPassword(passwordEncoder.encode("password"));  
        userRepository.save(user);  
    }  
}
@Component  
public class DataLoader implements CommandLineRunner {  
  
    @Autowired  
    private UserRepository userRepository;  
  
    @Autowired  
    private PasswordEncoder passwordEncoder;  
  
    @Override  
    public void run(String... args) throws Exception {  
        User user = new User();  
        user.setUsername("user");  
        user.setPassword(passwordEncoder.encode("password"));  
        userRepository.save(user);  
    }  
}