Controller

@RestController
@RequestMapping("/system/user")
public class SysUserController extends BaseController {

    @Log(title = "用户管理", businessType = BusinessType.EXPORT)
    @PreAuthorize("@ss.hasPermi('system:user:export')")
    @PostMapping("/export")
    public void export(HttpServletResponse response, SysUser user) {
        List<SysUser> list = userService.selectUserList(user);
        ExcelUtil<SysUser> util = new ExcelUtil<SysUser>(SysUser.class);
        util.exportExcel(response, list, "用户数据");
    }

    @Log(title = "用户管理", businessType = BusinessType.IMPORT)
    @PreAuthorize("@ss.hasPermi('system:user:import')")
    @PostMapping("/importData")
    public AjaxResult importData(MultipartFile file, boolean updateSupport) throws Exception {
        ExcelUtil<SysUser> util = new ExcelUtil<SysUser>(SysUser.class);
        List<SysUser> userList = util.importExcel(file.getInputStream());
        String operName = getUsername();
        String message = userService.importUser(userList, updateSupport, operName);
        return AjaxResult.success(message);
    }

    @PostMapping("/importTemplate")
    public void importTemplate(HttpServletResponse response) {
        ExcelUtil<SysUser> util = new ExcelUtil<SysUser>(SysUser.class);
        util.importTemplateExcel(response, "用户数据");
    }
}

Service

public interface ISysUserService extends IService<SysUser> {
    /**
     * 导入用户数据
     *
     * @param userList        用户数据列表
     * @param isUpdateSupport 是否更新支持，如果已存在，则进行更新数据
     * @param operName        操作用户
     * @return 结果
     */
    String importUser(List<SysUser> userList, Boolean isUpdateSupport, String operName);
}

Impl

@Service
public class SysUserServiceImpl extends ServiceImpl<SysUserMapper, SysUser> implements ISysUserService {

   /**
     * 导入用户数据
     *
     * @param userList        用户数据列表
     * @param isUpdateSupport 是否更新支持，如果已存在，则进行更新数据
     * @param operName        操作用户
     * @return 结果
     */
    @Override
    public String importUser(List<SysUser> userList, Boolean isUpdateSupport, String operName) {
        if (StringUtils.isNull(userList) || userList.size() == 0) {
            throw new ServiceException("导入用户数据不能为空！");
        }
        int successNum = 0;
        int failureNum = 0;
        StringBuilder successMsg = new StringBuilder();
        StringBuilder failureMsg = new StringBuilder();
        String password = configService.selectConfigByKey("sys.user.initPassword");
        for (SysUser user : userList) {
            try {
                // 验证是否存在这个用户
                SysUser u = baseMapper.selectUserByUserName(user.getUserName());
                if (StringUtils.isNull(u)) {
                    BeanValidators.validateWithException(validator, user);
                    user.setPassword(SecurityUtils.encryptPassword(password));
                    user.setCreateBy(operName);
                    this.insertUser(user);
                    successNum++;
                    successMsg.append("<br/>" + successNum + "、账号 " + user.getUserName() + " 导入成功");
                } else if (isUpdateSupport) {
                    BeanValidators.validateWithException(validator, user);
                    user.setUpdateBy(operName);
                    this.updateUser(user);
                    successNum++;
                    successMsg.append("<br/>" + successNum + "、账号 " + user.getUserName() + " 更新成功");
                } else {
                    failureNum++;
                    failureMsg.append("<br/>" + failureNum + "、账号 " + user.getUserName() + " 已存在");
                }
            } catch (Exception e) {
                failureNum++;
                String msg = "<br/>" + failureNum + "、账号 " + user.getUserName() + " 导入失败：";
                failureMsg.append(msg + e.getMessage());
                log.error(msg, e);
            }
        }
        if (failureNum > 0) {
            failureMsg.insert(0, "很抱歉，导入失败！共 " + failureNum + " 条数据格式不正确，错误如下：");
            throw new ServiceException(failureMsg.toString());
        } else {
            successMsg.insert(0, "恭喜您，数据已全部导入成功！共 " + successNum + " 条，数据如下：");
        }
        return successMsg.toString();
    }
}

部分源码

导入导出方法

public class ExcelUtil<T> {
    /**
     * 实体对象
     */
    public Class<T> clazz;

    //有参构造
    public ExcelUtil(Class<T> clazz) {
        this.clazz = clazz;
    }

    /**
     * 对list数据源将其里面的数据导入到excel表单
     *
     * @param response  返回数据
     * @param list      导出数据集合
     * @param sheetName 工作表的名称
     * @return 结果
     * @throws IOException
     */
    public void exportExcel(HttpServletResponse response, List<T> list, String sheetName) {
        exportExcel(response, list, sheetName, StringUtils.EMPTY);
    }

    /**
     * 对excel表单默认第一个索引名转换成list
     *
     * @param is 输入流
     * @return 转换后集合
     */
    public List<T> importExcel(InputStream is) throws Exception {
        return importExcel(is, 0);
    }

    /**
     * 对list数据源将其里面的数据导入到excel表单
     *
     * @param sheetName 工作表的名称
     * @return 结果
     */
    public void importTemplateExcel(HttpServletResponse response, String sheetName) {
        importTemplateExcel(response, sheetName, StringUtils.EMPTY);
    }
}

HttpServletResponse

HttpServletResponse详解