ExcelKit

<dependency>
    <groupId>com.wuwenze</groupId>
    <artifactId>ExcelKit</artifactId>
    <version>2.0.72</version>
</dependency>

@Excel("用户信息")
public class User {
  @ExcelField(value = "编号", width = 30)
  private Integer userId;
  @ExcelField(//value = "用户名",//required = true,//validator = UsernameValidator.class,//
      comment = "请填写用户名，最大长度为12，且不能重复"
  )
  private String username;
  @ExcelField(value = "密码", required = true, maxLength = 32)
  private String password;
  @ExcelField(value = "邮箱", validator = UserEmailValidator.class)
  private String email;
  @ExcelField(//value = "性别",//readConverterExp = "未知=0,男=1,女=2",//writeConverterExp = "0=未知,1=男,2=女",//options = SexOptions.class//
  )
  private Integer sex;
  @ExcelField(//value = "用户组",//name = "userGroup.name",//options = UserGroupNameOptions.class
  )
  private UserGroup userGroup;
  @ExcelField(value = "创建时间", dateFormat = "yyyy/MM/dd HH:mm:ss")
  private Date createAt;
  @ExcelField(//value = "自定义字段",//maxLength = 80,//comment = "可以乱填，但是长度不能超过80，导入时最终会转换为数字",//writeConverter = CustomizeFieldWriteConverter.class,// 写文件时，将数字转字符串
      readConverter = CustomizeFieldReadConverter.class// 读文件时，将字符串转数字
  )
  private Integer customizeField;
  // Getter and Setter ..
}

public class User2 {
  private Integer userId;
  private String username;
  private String password;
  private String email;
  private Integer sex;
  private UserGroup userGroup;
  private Date createAt;
  private Integer customizeField;
  // Getter and Setter ..
}

<?xml version="1.0" encoding="UTF-8"?>
<excel-mapping name="用户信息">
    <property name="userId" column="编号" width="30"/>
    <property
        name="username"
        column="用户名"
        required="true"
        validator="com.wuwenze.validator.UsernameValidator"
        comment="请填写用户名，最大长度为12，且不能重复"
      />
      <property name="password" column="密码" required="true" maxLength="32"/>
      <property name="email" column="邮箱" validator="com.wuwenze.validator.UserEmailValidator"/><property
        name="sex"
        column="性别"
        readConverterExp="未知=0,男=1,女=2"
        writeConverterExp="0=未知,1=男,2=女"
        options="com.wuwenze.options.SexOptions"
      />
      <property name="userGroup.name" column="用户组" options="com.wuwenze.options.UserGroupNameOptions"/><property name="createAt" column="创建时间" dateFormat="yyyy/MM/dd HH:mm:ss"/><property
        name="customizeField"
        column="自定义字段"
        maxLength="80"
        comment="可以乱填，但是长度不能超过80，导入时最终会转换为数字"
        writeConverter="com.wuwenze.converter.CustomizeFieldWriteConverter"
        readConverter="com.wuwenze.converter.CustomizeFieldReadConverter"
      />
  </excel-mapping>

public class UserGroupNameOptions implements Options {
  @Overridepublic String[] get() {
    return new String[]{"管理组", "普通会员组", "游客"};
  }
}
public class UsernameValidator implements Validator {
  final List<String> ERROR_USERNAME_LIST = Lists.newArrayList(
      "admin", "root", "master", "administrator", "sb"
  );
  @Overridepublic String valid(Object o) {
    String username = (String) o;
    if (username.length() > 12) {
      return "用户名不能超过12个字符。";
    }
    if (ERROR_USERNAME_LIST.contains(username)) {
      return "用户名非法，不允许使用。";
    }
    return null;
  }
}
public class CustomizeFieldWriteConverter implements WriteConverter {
  /**
   * 写文件时，将值进行转换（此处示例为将数值拼接为指定格式的字符串）
   */@Overridepublic String convert(Object o) throws ExcelKitWriteConverterException {
    return (o + "_convertedValue");
  }
}
public class CustomizeFieldReadConverter implements ReadConverter {
  /**
   * 读取单元格时，将值进行转换（此处示例为计算单元格字符串char的总和）
   */@Overridepublic Object convert(Object o) throws ExcelKitReadConverterException {
    String value = (String) o;
    int convertedValue = 0;
    for (char c : value.toCharArray()) {
      convertedValue += Integer.valueOf(c);
    }
    return convertedValue;
  }
}

// 生成导入模板（含3条示例数据）@RequestMapping(value = "/downTemplate", method = RequestMethod.GET)
public void downTemplate(HttpServletResponse response) {
  List<User> userList = DbUtil.getUserList(3);
  ExcelKit.$Export(User.class, response).downXlsx(userList, true);
}

@RequestMapping(value = "/importUser", method = RequestMethod.POST)
public ResponseEntity<?> importUser(@RequestParam MultipartFile file)
    throws IOException {
  long beginMillis = System.currentTimeMillis();
  List<User> successList = Lists.newArrayList();
  List<Map<String, Object>> errorList = Lists.newArrayList();
  ExcelKit.$Import(User.class)
      .readXlsx(file.getInputStream(), new ExcelReadHandler<User>() {
        @Overridepublic void onSuccess(int sheetIndex, int rowIndex, User entity) {
          successList.add(entity); // 单行读取成功，加入入库队列。
        }
        @Overridepublic void onError(int sheetIndex, int rowIndex,
            List<ExcelErrorField> errorFields) {
          // 读取数据失败，记录了当前行所有失败的数据
          errorList.add(MapUtil.newHashMap(//"sheetIndex", sheetIndex,//"rowIndex", rowIndex,//"errorFields", errorFields//
          ));
        }
      });
  // TODO: 执行successList的入库操作。return ResponseEntity.ok(MapUtil.newHashMap(
      "data", successList,
      "haveError", !CollectionUtil.isEmpty(errorList),
      "error", errorList,
      "timeConsuming", (System.currentTimeMillis() - beginMillis) / 1000L
  ));
}

@RequestMapping(value = "/downXlsx", method = RequestMethod.GET)
public void downXlsx(HttpServletResponse response) {
  long beginMillis = System.currentTimeMillis();
  List<User> userList = DbUtil.getUserList(100000);// 生成10w条测试数据ExcelKit.$Export(User.class, response).downXlsx(userList, false);
  log.info("#ExcelKit.$Export success, size={},timeConsuming={}s",//
      userList.size(), (System.currentTimeMillis() - beginMillis) / 1000L);
}