springboot exception 状态码

在 Spring Boot 中，可以使用 @ExceptionHandler 注解来处理异常，并返回指定的状态码。可以使用 @ResponseStatus 注解来指定返回的 HTTP 状态码。示例代码如下：

@RestController
public class MyController {

  @ExceptionHandler(Exception.class)
  @ResponseStatus(HttpStatus.INTERNAL_SERVER_ERROR)
  public String handleException(Exception ex) {
    return "Error: " + ex.getMessage();
  }

  //其他方法代码
}

在上面的代码中，当抛出 Exception 类型的异常时，会返回状态码为 500 的 HTTP 响应，并将异常信息包装在返回结果中。可以根据实际需要修改 @ResponseStatus 注解中的状态码。

相关问题

springboot扫码登录

以下是一个简单的Spring Boot扫码登录示例代码，使用了Google提供的ZXing扫码库和Spring Security：

1. 在pom.xml文件中添加依赖：

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

<dependency>
    <groupId>com.google.zxing</groupId>
    <artifactId>core</artifactId>
    <version>3.4.1</version>
</dependency>

<dependency>
    <groupId>com.google.zxing</groupId>
    <artifactId>javase</artifactId>
    <version>3.4.1</version>
</dependency>

2. 创建一个实体类用于存储扫码登录状态：

@Entity
public class QrCodeLogin {
    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    private Long id;

    private String code;

    @OneToOne
    private User user;

    private boolean used;

    // getter and setter...
}

3. 创建一个Controller用于生成和验证扫码登录二维码：

@RestController
@RequestMapping("/qrcode")
public class QrCodeController {
    private final QrCodeLoginRepository qrCodeLoginRepository;

    public QrCodeController(QrCodeLoginRepository qrCodeLoginRepository) {
        this.qrCodeLoginRepository = qrCodeLoginRepository;
    }

    @GetMapping
    public ResponseEntity<byte[]> generateQrCode(HttpSession session) throws WriterException, IOException {
        User user = (User) SecurityContextHolder.getContext().getAuthentication().getPrincipal();

        // 生成唯一的二维码字符串
        String code = UUID.randomUUID().toString();

        // 保存二维码信息到数据库中
        QrCodeLogin qrCodeLogin = new QrCodeLogin();
        qrCodeLogin.setCode(code);
        qrCodeLogin.setUser(user);
        qrCodeLogin.setUsed(false);
        qrCodeLoginRepository.save(qrCodeLogin);

        // 生成二维码图片
        ByteArrayOutputStream out = new ByteArrayOutputStream();
        QRCodeWriter writer = new QRCodeWriter();
        BitMatrix bitMatrix = writer.encode(code, BarcodeFormat.QR_CODE, 200, 200);
        MatrixToImageWriter.writeToStream(bitMatrix, "png", out);
        byte[] imageBytes = out.toByteArray();

        // 将二维码字符串保存到session中
        session.setAttribute("qrCode", code);

        // 返回二维码图片
        HttpHeaders headers = new HttpHeaders();
        headers.setContentType(MediaType.IMAGE_PNG);
        return new ResponseEntity<>(imageBytes, headers, HttpStatus.OK);
    }

    @GetMapping("/check")
    public ResponseEntity<String> checkQrCode(HttpSession session) {
        User user = (User) SecurityContextHolder.getContext().getAuthentication().getPrincipal();

        // 从session中获取二维码字符串
        String code = (String) session.getAttribute("qrCode");

        // 根据二维码字符串从数据库中获取扫码信息
        QrCodeLogin qrCodeLogin = qrCodeLoginRepository.findByCode(code);

        if (qrCodeLogin != null && !qrCodeLogin.isUsed() && qrCodeLogin.getUser().equals(user)) {
            // 将扫码信息标记为已使用
            qrCodeLogin.setUsed(true);
            qrCodeLoginRepository.save(qrCodeLogin);

            // 清除session中的二维码字符串
            session.removeAttribute("qrCode");

            return ResponseEntity.ok("登录成功");
        } else {
            return ResponseEntity.ok("登录失败");
        }
    }
}

4. 在Spring Security配置类中添加扫码登录相关配置：

@Configuration
@EnableWebSecurity
public class SecurityConfig extends WebSecurityConfigurerAdapter {
    private final UserDetailsService userDetailsService;
    private final PasswordEncoder passwordEncoder;
    private final QrCodeAuthenticationProvider qrCodeAuthenticationProvider;

    public SecurityConfig(UserDetailsService userDetailsService, PasswordEncoder passwordEncoder, QrCodeAuthenticationProvider qrCodeAuthenticationProvider) {
        this.userDetailsService = userDetailsService;
        this.passwordEncoder = passwordEncoder;
        this.qrCodeAuthenticationProvider = qrCodeAuthenticationProvider;
    }

    @Override
    protected void configure(HttpSecurity http) throws Exception {
        http
            .authorizeRequests()
                .antMatchers("/login/**", "/qrcode/**").permitAll()
                .anyRequest().authenticated()
                .and()
            .formLogin()
                .loginPage("/login")
                .defaultSuccessUrl("/")
                .and()
            .logout()
                .logoutUrl("/logout")
                .logoutSuccessUrl("/login")
                .and()
            .addFilterBefore(qrCodeAuthenticationFilter(), UsernamePasswordAuthenticationFilter.class)
            .authenticationProvider(qrCodeAuthenticationProvider);
    }

    @Override
    protected void configure(AuthenticationManagerBuilder auth) throws Exception {
        auth.userDetailsService(userDetailsService).passwordEncoder(passwordEncoder);
        auth.authenticationProvider(qrCodeAuthenticationProvider);
    }

    private QrCodeAuthenticationFilter qrCodeAuthenticationFilter() throws Exception {
        QrCodeAuthenticationFilter qrCodeAuthenticationFilter = new QrCodeAuthenticationFilter();
        qrCodeAuthenticationFilter.setAuthenticationManager(authenticationManager());
        qrCodeAuthenticationFilter.setAuthenticationSuccessHandler(new QrCodeAuthenticationSuccessHandler());
        return qrCodeAuthenticationFilter;
    }
}

5. 创建一个QrCodeAuthenticationFilter用于处理扫码登录请求：

public class QrCodeAuthenticationFilter extends AbstractAuthenticationProcessingFilter {
    public QrCodeAuthenticationFilter() {
        super(new AntPathRequestMatcher("/qrcode/login", "POST"));
    }

    @Override
    public Authentication attemptAuthentication(HttpServletRequest request, HttpServletResponse response) throws AuthenticationException, IOException, ServletException {
        String code = request.getParameter("code");

        QrCodeAuthenticationToken token = new QrCodeAuthenticationToken(code);

        return this.getAuthenticationManager().authenticate(token);
    }
}

6. 创建一个QrCodeAuthenticationToken用于存储扫码登录信息：

public class QrCodeAuthenticationToken extends AbstractAuthenticationToken {
    private final String code;

    public QrCodeAuthenticationToken(String code) {
        super(null);

        this.code = code;
    }

    @Override
    public Object getCredentials() {
        return null;
    }

    @Override
    public Object getPrincipal() {
        return null;
    }

    public String getCode() {
        return code;
    }
}

7. 创建一个QrCodeAuthenticationProvider用于处理扫码登录验证：

public class QrCodeAuthenticationProvider implements AuthenticationProvider {
    private final QrCodeLoginRepository qrCodeLoginRepository;

    public QrCodeAuthenticationProvider(QrCodeLoginRepository qrCodeLoginRepository) {
        this.qrCodeLoginRepository = qrCodeLoginRepository;
    }

    @Override
    public Authentication authenticate(Authentication authentication) throws AuthenticationException {
        String code = (String) authentication.getCredentials();

        QrCodeLogin qrCodeLogin = qrCodeLoginRepository.findByCode(code);

        if (qrCodeLogin != null && !qrCodeLogin.isUsed()) {
            User user = qrCodeLogin.getUser();

            // 标记扫码信息为已使用
            qrCodeLogin.setUsed(true);
            qrCodeLoginRepository.save(qrCodeLogin);

            // 返回用户信息
            return new UsernamePasswordAuthenticationToken(user, null, user.getAuthorities());
        } else {
            throw new BadCredentialsException("扫码信息无效");
        }
    }

    @Override
    public boolean supports(Class<?> authentication) {
        return QrCodeAuthenticationToken.class.isAssignableFrom(authentication);
    }
}

8. 创建一个QrCodeAuthenticationSuccessHandler用于处理扫码登录成功后的跳转：

public class QrCodeAuthenticationSuccessHandler extends SimpleUrlAuthenticationSuccessHandler {
    @Override
    public void onAuthenticationSuccess(HttpServletRequest request, HttpServletResponse response, Authentication authentication) throws IOException, ServletException {
        response.setStatus(HttpServletResponse.SC_OK);
    }
}

以上代码仅为示例，实际应用中还需要根据具体业务逻辑进行修改。

springboot filter的try cache导致http状态码为200

Spring Boot Filter 中的 try catch 块可能会导致 HTTP 状态码为 200 的问题。这是因为 catch 块中的代码可能不会正确地处理异常，而是简单地返回一个 HTTP 200 响应码。为了解决这个问题，建议在 catch 块中使用 HttpServletResponse 的 sendError() 方法来设置正确的 HTTP 状态码和错误信息。具体实现可以参考以下示例代码：

@Override
public void doFilter(ServletRequest request, ServletResponse response, FilterChain chain) throws IOException, ServletException {
    try {
        // 过滤器逻辑代码
        chain.doFilter(request, response);
    } catch (Exception e) {
        HttpServletResponse httpResponse = (HttpServletResponse) response;
        httpResponse.sendError(HttpServletResponse.SC_INTERNAL_SERVER_ERROR, "Internal Server Error");
    }
}

在上述示例中，当过滤器逻辑代码中发生异常时，会将 HTTP 状态码设置为 500，并返回错误信息 "Internal Server Error"。这样可以确保客户端能够正确地处理异常情况。