【文档小记】Atlantis JMVT 游戏车队交流平台

// Config class
@Configuration
public class CorsConfig {

    // 当前跨域请求最大有效时长。1天
    private static final long MAX_AGE = 24 * 60 * 60;

    @Bean
    public CorsFilter corsFilter() {
        UrlBasedCorsConfigurationSource source = new UrlBasedCorsConfigurationSource();
        CorsConfiguration corsConfiguration = new CorsConfiguration();
        corsConfiguration.addAllowedOrigin("*"); // 1 设置访问源地址
        // corsConfiguration addAllowedOriginsPattern("*");
        corsConfiguration.addAllowedHeader("*"); // 2 设置访问源请求头
        corsConfiguration.addAllowedMethod("*"); // 3 设置访问源请求方法
        // corsConfiguration.setAllowCredentials(true); // 解决前后的session对象不一致问题
        corsConfiguration.setMaxAge(MAX_AGE);
        source.registerCorsConfiguration("/**", corsConfiguration); // 4 对接口配置跨域设置
        System.out.println("doing CORS config...");
        return new CorsFilter(source);
    }
}

// filter class. Need to add 'ServletComponentScan' at Application class
@WebFilter(filterName = "requestFilter", urlPatterns = {"/*"})
public class RequestFilter implements Filter {

    @Override
    public void init(FilterConfig filterConfig) throws ServletException {
    }

    @Override
    public void doFilter(ServletRequest servletRequest, ServletResponse servletResponse, FilterChain  filterChain)
        throws IOException, ServletException {

        System.out.println("doing request filter...");

        HttpServletResponse response = (HttpServletResponse) servletResponse;
        HttpServletRequest request = (HttpServletRequest) servletRequest;

        // 此处 setHeader、addHeader 方法都可用。但 addHeader时写多个会报错：“...,but only one is allowed”
        response.setHeader("Access-Control-Allow-Origin", "*");
        // response.addHeader("Access-Control-Allow-Origin", request.getHeader("origin"));
        // 解决预请求（发送2次请求），此问题也可在 nginx 中作相似设置解决。
        response.setHeader("Access-Control-Allow-Headers",
                "x-requested-with,Cache-Control,Pragma,Content-Type,Token, Content-Type");
        response.setHeader("Access-Control-Allow-Methods", "POST, GET, OPTIONS, PUT, DELETE");
        response.setHeader("Access-Control-Max-Age", "3600");
        response.setHeader("Access-Control-Allow-Credentials", "true");
        String method = request.getMethod();
        if (method.equalsIgnoreCase("OPTIONS")) {
            servletResponse.getOutputStream().write("Success".getBytes("utf-8"));
        } else {
            filterChain.doFilter(servletRequest, servletResponse);
        }
    }

    @Override
    public void destroy() {
    }
}

@Configuration
public class CorsConfig {

    // 当前跨域请求最大有效时长。1天
    private static final long MAX_AGE = 24 * 60 * 60;

    @Bean
    public CorsFilter corsFilter() {
        UrlBasedCorsConfigurationSource source = new UrlBasedCorsConfigurationSource();
        CorsConfiguration corsConfiguration = new CorsConfiguration();

        System.out.println("doing CORS config...");
        // corsConfiguration.addAllowedOrigin("*"); // 设置访问源地址
        //
        corsConfiguration.addAllowedOriginPattern("**");
        corsConfiguration.addAllowedHeader("*"); // 设置访问源请求头
        corsConfiguration.addAllowedMethod("*"); // 设置访问源请求方法
        //
        corsConfiguration.setAllowCredentials(true); // 解决前后的session对象不一致问题

        corsConfiguration.setMaxAge(MAX_AGE);
        source.registerCorsConfiguration("/**", corsConfiguration); // 对接口配置跨域设置
        return new CorsFilter(source);
    }
}

// 关系：泛型ServiceImpl类实现泛型接口Service类。接口AdminService类继承泛型泛型接口Service类。AdminServiceImpl类继承泛型ServiceImp类，同时实现接口AdminService类。
// BaseService<T>
public interface BaseService<T> {
    public T getById(Integer id);
    public List<T> getAll();
    public boolean insert(T obj);
    public boolean update(T obj);
    public boolean updateInfo(T obj);
    public boolean updatePwd(T obj);
    public boolean delete(Integer id);
    public T login(T login);
}
// BaseServiceImpl<T>
public abstract class BaseServiceImpl<T> implements BaseService<T> {
    @Autowired
    // 代理对象自动装配，SpringBoot无法识别
    // userDao实例可能会报错，修改检查配置
    // protected 子类可继承
    protected BaseMapper<T> baseMapper;

    @Override
    public T getById(Integer id) {
        return baseMapper.getById(id);
    }

    @Override
    public List<T> getAll() {
        return new ArrayList<T>(baseMapper.getAll());
    }

    @Override
    public boolean insert(T obj) {
        return false;
    }

    @Override
    public boolean update(T obj) {
        return (baseMapper.update(obj) == 1);
    }

    @Override
    public boolean updateInfo(T obj) {
        return false;
    }

    @Override
    public boolean updatePwd(T obj)
    {
        return false;
    }

    @Override
    public boolean delete(Integer id) {
        return (baseMapper.delete(id) == 1);
    }

    @Override
    public T login(T login) {
        return null;
    }
}
// AdminService
public interface AdminService extends BaseService<Admin> {
}
// AdminServiceImpl
// IoC容器管理对象
@Service
public class AdminServiceImpl extends BaseServiceImpl<Admin> implements AdminService {

    @Override
    public boolean updateInfo(Admin admin) {
        return (baseMapper.updateInfo(admin) == 1);
    @Override
    public boolean updatePwd(Admin admin) {
        return (baseMapper.updatePwd(admin) == 1);
    }

    @Override
    public boolean insert(Admin admin) {
        // 查询数据库发现没有同名用户
        if (baseMapper.getByUsername(admin.getUsername()) == null)
        {
            return (baseMapper.insert(admin) == 1);
        }
        else
        {
            return false;
        }
    }

    @Override
    public Admin login(Admin login)
    {
        return (baseMapper.getByUsernameAndPassword(login.getUsername(), login.getPassword()));
    }
}

// basePath定义在 application.yml 配置文件中
// 用户的头像上传
@PostMapping("/upload/{id}")
public Result upload(MultipartFile file, @PathVariable Integer id)
{
    System.out.println("uploading...");
    // 获取的file是临时文件，需要转存

    File filePath = new File(basePath);
    // 若目录不存在，创建
    if (!filePath.exists())
    {
        filePath.mkdirs();
    }

    // 获取原始文件名后缀
    // String postfix = Objects.requireNonNull(
    //                    file.getOriginalFilename()).substring(
    //                            (file.getOriginalFilename().lastIndexOf(".")));

    // 根据id重新生成用户名
    // 文件上传加入后缀 '.png'
    String fileName = "userId_" + id.toString() + ".png";

    // 转存文件
    try {
        file.transferTo(new File(basePath + fileName));
    }
    catch (IOException e) {
        throw new SystemException("upload failed", e, Code.SYS_ERR);
    }

    return new Result(Code.UPLOAD_OK, (String)fileName, "upload succeeded");
}

// 用户头像下载
@GetMapping("/download/{id}")
public Result download(HttpServletResponse response, @PathVariable Integer id)
{
    try
    {
        // 输入流读取文件内容
        FileInputStream fis = new FileInputStream(basePath + "userId_" + id.toString() + ".png");
        // 输出流写回浏览器
        ServletOutputStream sos = response.getOutputStream();
        response.setContentType("image/png");

        int len = 0;
        byte[] bytes = new byte[1024];
        while ((len = fis.read(bytes)) != -1)
        {
            sos.write(bytes, 0, len);
            sos.flush();
        }

        //close
        fis.close();
        sos.close();
    }
    catch (Exception e)
    {
        e.printStackTrace();
        return new Result(Code.DOWNLOAD_ERR, null, "no user photo");
    }

    return new Result(Code.DOWNLOAD_OK,
                    basePath + "userId_" + id.toString() + ".png",
                    "download succeeded");
}

// BaseService interface
public interface BaseService<T> {
    public PageInfo<T> getAllByPage(int pageNum, int pageSize);
}
// BaseServiceImpl 
public abstract class BaseServiceImpl<T> implements BaseService<T> {
    @Override
    public PageInfo<T> getAllByPage(int pageNum, int pageSize) {
        PageHelper.startPage(pageNum, pageSize);
        List<T> baseList = baseMapper.getAll();
        return new PageInfo<T>(baseList);
    }
}
// BaseController
public abstract class BaseController<T> {
    @GetMapping("/{pageNum}/{pageSize}")
    public Result getAllByPage(@PathVariable Integer pageNum, @PathVariable Integer pageSize)
    {
        try
        {
            PageInfo<T> pageInfo = baseService.getAllByPage(pageNum, pageSize);
            Integer code = pageInfo != null ? Code.GET_OK : Code.GET_ERR;
            String msg = pageInfo != null ? "get succeeded" : "get failed";
            return new Result(code, pageInfo, msg);
        }
        catch (SystemException e)
        {
            throw new SystemException("unknown error occurred", Code.SYS_ERR);
        }
    }
}

// 后端
// 上传，Controller层
// 文章内图片上传
@PostMapping("/upload")
public Result upload(MultipartFile file)
{
    System.out.println("uploading...");
    // 获取的file是临时文件，需要转存

    File filePath = new File(basePath);
    // 若目录不存在，创建
    if (!filePath.exists())
    {
        filePath.mkdirs();
    }

    // 获取原始文件名后缀
    String postfix = Objects.requireNonNull(
                        file.getOriginalFilename()).substring(
                                (file.getOriginalFilename().lastIndexOf(".")));

    // 重新命名
    String fileName = GenerateMD5.encrypt(file.getOriginalFilename()) + postfix;

    // 转存文件
    try {
        file.transferTo(new File(basePath + fileName));
    }
    catch (IOException e) {
        throw new SystemException("upload failed", e, Code.SYS_ERR);
    }

    return new Result(Code.UPLOAD_OK, fileName, "upload succeeded");
}
// 下载，采用 URL 磁盘映射
// WebMvcConfig
@Configuration
public class WebMvcConfig extends WebMvcConfigurerAdapter {
    // basePath 通过 application.yml 注入，是磁盘上的绝对路径
    @Value("${atlantis.articlePicturesBasePath}")
    private String basePath;

    @Override
    public void addResourceHandlers(ResourceHandlerRegistry registry) {
        registry.addResourceHandler("/newsArticles/download/**")
                .addResourceLocations("file:" + basePath);
    }
}