常用工具类：

    1.POI工具类：
        import org.apache.poi.hssf.usermodel.HSSFWorkbook;
        import org.apache.poi.ss.usermodel.Cell;
        import org.apache.poi.ss.usermodel.Row;
        import org.apache.poi.ss.usermodel.Sheet;
        import org.apache.poi.ss.usermodel.Workbook;
        import org.apache.poi.xssf.usermodel.XSSFWorkbook;
        import org.springframework.web.multipart.MultipartFile;

        import java.io.FileNotFoundException;
        import java.io.IOException;
        import java.io.InputStream;
        import java.text.SimpleDateFormat;
        import java.util.ArrayList;
        import java.util.List;

        public class POIUtils {
            private final static String xls = "xls";
            private final static String xlsx = "xlsx";
            private final static String DATE_FORMAT = "yyyy/MM/dd";
            /**
             * 读入excel文件，解析后返回
             * @param file
             * @throws IOException
             */
            public static List<String[]> readExcel(MultipartFile file) throws IOException {
                //检查文件
                checkFile(file);
                //获得Workbook工作薄对象
                Workbook workbook = getWorkBook(file);
                //创建返回对象，把每行中的值作为一个数组，所有行作为一个集合返回
                List<String[]> list = new ArrayList<String[]>();
                if(workbook != null){
                    for(int sheetNum = 0;sheetNum < workbook.getNumberOfSheets();sheetNum++){
                        //获得当前sheet工作表
                        Sheet sheet = workbook.getSheetAt(sheetNum);
                        if(sheet == null){
                            continue;
                        }
                        //获得当前sheet的开始行
                        int firstRowNum  = sheet.getFirstRowNum();
                        //获得当前sheet的结束行
                        int lastRowNum = sheet.getLastRowNum();
                        //循环除了第一行的所有行
                        for(int rowNum = firstRowNum+1;rowNum <= lastRowNum;rowNum++){
                            //获得当前行
                            Row row = sheet.getRow(rowNum);
                            if(row == null){
                                continue;
                            }
                            //获得当前行的开始列
                            int firstCellNum = row.getFirstCellNum();
                            //获得当前行的列数
                            int lastCellNum = row.getPhysicalNumberOfCells();
                            String[] cells = new String[row.getPhysicalNumberOfCells()];
                            //循环当前行
                            for(int cellNum = firstCellNum; cellNum < lastCellNum;cellNum++){
                                Cell cell = row.getCell(cellNum);
                                cells[cellNum] = getCellValue(cell);
                            }
                            list.add(cells);
                        }
                    }
                    workbook.close();
                }
                return list;
            }

            //校验文件是否合法
            public static void checkFile(MultipartFile file) throws IOException{
                //判断文件是否存在
                if(null == file){
                    throw new FileNotFoundException("文件不存在！");
                }
                //获得文件名
                String fileName = file.getOriginalFilename();
                //判断文件是否是excel文件
                if(!fileName.endsWith(xls) && !fileName.endsWith(xlsx)){
                    throw new IOException(fileName + "不是excel文件");
                }
            }
            public static Workbook getWorkBook(MultipartFile file) {
                //获得文件名
                String fileName = file.getOriginalFilename();
                //创建Workbook工作薄对象，表示整个excel
                Workbook workbook = null;
                try {
                    //获取excel文件的io流
                    InputStream is = file.getInputStream();
                    //根据文件后缀名不同(xls和xlsx)获得不同的Workbook实现类对象
                    if(fileName.endsWith(xls)){
                        //2003
                        workbook = new HSSFWorkbook(is);
                    }else if(fileName.endsWith(xlsx)){
                        //2007
                        workbook = new XSSFWorkbook(is);
                    }
                } catch (IOException e) {
                    e.printStackTrace();
                }
                return workbook;
            }
            public static String getCellValue(Cell cell){
                String cellValue = "";
                if(cell == null){
                    return cellValue;
                }
                //如果当前单元格内容为日期类型，需要特殊处理
                String dataFormatString = cell.getCellStyle().getDataFormatString();
                if(dataFormatString.equals("m/d/yy")){
                    cellValue = new SimpleDateFormat(DATE_FORMAT).format(cell.getDateCellValue());
                    return cellValue;
                }
                //把数字当成String来读，避免出现1读成1.0的情况
                if(cell.getCellType() == Cell.CELL_TYPE_NUMERIC){
                    cell.setCellType(Cell.CELL_TYPE_STRING);
                }
                //判断数据的类型
                switch (cell.getCellType()){
                    case Cell.CELL_TYPE_NUMERIC: //数字
                        cellValue = String.valueOf(cell.getNumericCellValue());
                        break;
                    case Cell.CELL_TYPE_STRING: //字符串
                        cellValue = String.valueOf(cell.getStringCellValue());
                        break;
                    case Cell.CELL_TYPE_BOOLEAN: //Boolean
                        cellValue = String.valueOf(cell.getBooleanCellValue());
                        break;
                    case Cell.CELL_TYPE_FORMULA: //公式
                        cellValue = String.valueOf(cell.getCellFormula());
                        break;
                    case Cell.CELL_TYPE_BLANK: //空值
                        cellValue = "";
                        break;
                    case Cell.CELL_TYPE_ERROR: //故障
                        cellValue = "非法字符";
                        break;
                    default:
                        cellValue = "未知类型";
                        break;
                }
                return cellValue;
            }
        }
    
    2.日期工具类：
        import java.text.SimpleDateFormat;
        import java.util.*;

        /**
         * 日期操作工具类
         */
        public class DateUtils {
            /**
             * 日期转换-  String -> Date
             *
             * @param dateString 字符串时间
             * @return Date类型信息
             * @throws Exception 抛出异常
             */
            public static Date parseString2Date(String dateString) throws Exception {
                if (dateString == null) {
                    return null;
                }
                return parseString2Date(dateString, "yyyy-MM-dd");
            }

            /**
             * 日期转换-  String -> Date
             *
             * @param dateString 字符串时间
             * @param pattern    格式模板
             * @return Date类型信息
             * @throws Exception 抛出异常
             */
            public static Date parseString2Date(String dateString, String pattern) throws Exception {
                if (dateString == null) {
                    return null;
                }
                SimpleDateFormat sdf = new SimpleDateFormat(pattern);
                Date date = sdf.parse(dateString);
                return date;
            }

            /**
             * 日期转换 Date -> String
             *
             * @param date Date类型信息
             * @return 字符串时间
             * @throws Exception 抛出异常
             */
            public static String parseDate2String(Date date) throws Exception {
                if (date == null) {
                    return null;
                }
                return parseDate2String(date, "yyyy-MM-dd");
            }

            /**
             * 日期转换 Date -> String
             *
             * @param date    Date类型信息
             * @param pattern 格式模板
             * @return 字符串时间
             * @throws Exception 抛出异常
             */
            public static String parseDate2String(Date date, String pattern) throws Exception {
                if (date == null) {
                    return null;
                }
                SimpleDateFormat sdf = new SimpleDateFormat(pattern);
                String strDate = sdf.format(date);
                return strDate;
            }

            /**
             * 获取当前日期的本周一是几号
             *
             * @return 本周一的日期
             */
            public static Date getThisWeekMonday() {
                Calendar cal = Calendar.getInstance();
                cal.setTime(new Date());
                // 获得当前日期是一个星期的第几天
                int dayWeek = cal.get(Calendar.DAY_OF_WEEK);
                if (1 == dayWeek) {
                    cal.add(Calendar.DAY_OF_MONTH, -1);
                }
                // 设置一个星期的第一天，按中国的习惯一个星期的第一天是星期一
                cal.setFirstDayOfWeek(Calendar.MONDAY);
                // 获得当前日期是一个星期的第几天
                int day = cal.get(Calendar.DAY_OF_WEEK);
                // 根据日历的规则，给当前日期减去星期几与一个星期第一天的差值
                cal.add(Calendar.DATE, cal.getFirstDayOfWeek() - day);
                return cal.getTime();
            }

            /**
             * 获取当前日期周的最后一天
             *
             * @return 当前日期周的最后一天
             */
            public static Date getSundayOfThisWeek() {
                Calendar c = Calendar.getInstance();
                int dayOfWeek = c.get(Calendar.DAY_OF_WEEK) - 1;
                if (dayOfWeek == 0) {
                    dayOfWeek = 7;
                }
                c.add(Calendar.DATE, -dayOfWeek + 7);
                return c.getTime();
            }

            /**
             * 根据日期区间获取月份列表
             *
             * @param minDate 开始时间
             * @param maxDate 结束时间
             * @return 月份列表
             * @throws Exception
             */
            public static List<String> getMonthBetween(String minDate, String maxDate, String format) throws Exception {
                ArrayList<String> result = new ArrayList<>();
                SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM");

                Calendar min = Calendar.getInstance();
                Calendar max = Calendar.getInstance();

                min.setTime(sdf.parse(minDate));
                min.set(min.get(Calendar.YEAR), min.get(Calendar.MONTH), 1);

                max.setTime(sdf.parse(maxDate));
                max.set(max.get(Calendar.YEAR), max.get(Calendar.MONTH), 2);
                SimpleDateFormat sdf2 = new SimpleDateFormat(format);

                Calendar curr = min;
                while (curr.before(max)) {
                    result.add(sdf2.format(curr.getTime()));
                    curr.add(Calendar.MONTH, 1);
                }

                return result;
            }

            /**
             * 根据日期获取年度中的周索引
             *
             * @param date 日期
             * @return 周索引
             * @throws Exception
             */
            public static Integer getWeekOfYear(String date) throws Exception {
                Date useDate = parseString2Date(date);
                Calendar cal = Calendar.getInstance();
                cal.setTime(useDate);
                return cal.get(Calendar.WEEK_OF_YEAR);
            }

            /**
             * 根据年份获取年中周列表
             *
             * @param year 年分
             * @return 周列表
             * @throws Exception
             */
            public static Map<Integer, String> getWeeksOfYear(String year) throws Exception {
                Date useDate = parseString2Date(year, "yyyy");
                Calendar cal = Calendar.getInstance();
                cal.setTime(useDate);
                //获取年中周数量
                int weeksCount = cal.getWeeksInWeekYear();
                Map<Integer, String> mapWeeks = new HashMap<>(55);
                for (int i = 0; i < weeksCount; i++) {
                    cal.get(Calendar.DAY_OF_YEAR);
                    mapWeeks.put(i + 1, parseDate2String(getFirstDayOfWeek(cal.get(Calendar.YEAR), i)));
                }
                return mapWeeks;
            }

            /**
             * 获取某年的第几周的开始日期
             *
             * @param year 年分
             * @param week 周索引
             * @return 开始日期
             * @throws Exception
             */
            public static Date getFirstDayOfWeek(int year, int week) throws Exception {
                Calendar c = new GregorianCalendar();
                c.set(Calendar.YEAR, year);
                c.set(Calendar.MONTH, Calendar.JANUARY);
                c.set(Calendar.DATE, 1);

                Calendar cal = (GregorianCalendar) c.clone();
                cal.add(Calendar.DATE, week * 7);

                return getFirstDayOfWeek(cal.getTime());
            }

            /**
             * 获取某年的第几周的结束日期
             *
             * @param year 年份
             * @param week 周索引
             * @return 结束日期
             * @throws Exception
             */
            public static Date getLastDayOfWeek(int year, int week) throws Exception {
                Calendar c = new GregorianCalendar();
                c.set(Calendar.YEAR, year);
                c.set(Calendar.MONTH, Calendar.JANUARY);
                c.set(Calendar.DATE, 1);

                Calendar cal = (GregorianCalendar) c.clone();
                cal.add(Calendar.DATE, week * 7);

                return getLastDayOfWeek(cal.getTime());
            }

            /**
             * 获取当前时间所在周的开始日期
             *
             * @param date 当前时间
             * @return 开始时间
             */
            public static Date getFirstDayOfWeek(Date date) {
                Calendar c = new GregorianCalendar();
                c.setFirstDayOfWeek(Calendar.SUNDAY);
                c.setTime(date);
                c.set(Calendar.DAY_OF_WEEK, c.getFirstDayOfWeek());
                return c.getTime();
            }

            /**
             * 获取当前时间所在周的结束日期
             *
             * @param date 当前时间
             * @return 结束日期
             */
            public static Date getLastDayOfWeek(Date date) {
                Calendar c = new GregorianCalendar();
                c.setFirstDayOfWeek(Calendar.SUNDAY);
                c.setTime(date);
                c.set(Calendar.DAY_OF_WEEK, c.getFirstDayOfWeek() + 6);
                return c.getTime();
            }
            //获得上周一的日期
            public static Date geLastWeekMonday(Date date) {
                Calendar cal = Calendar.getInstance();
                cal.setTime(getThisWeekMonday(date));
                cal.add(Calendar.DATE, -7);
                return cal.getTime();
            }

            //获得本周一的日期
            public static Date getThisWeekMonday(Date date) {
                Calendar cal = Calendar.getInstance();
                cal.setTime(date);
                // 获得当前日期是一个星期的第几天
                int dayWeek = cal.get(Calendar.DAY_OF_WEEK);
                if (1 == dayWeek) {
                    cal.add(Calendar.DAY_OF_MONTH, -1);
                }
                // 设置一个星期的第一天，按中国的习惯一个星期的第一天是星期一
                cal.setFirstDayOfWeek(Calendar.MONDAY);
                // 获得当前日期是一个星期的第几天
                int day = cal.get(Calendar.DAY_OF_WEEK);
                // 根据日历的规则，给当前日期减去星期几与一个星期第一天的差值
                cal.add(Calendar.DATE, cal.getFirstDayOfWeek() - day);
                return cal.getTime();
            }

            //获得下周一的日期
            public static Date getNextWeekMonday(Date date) {
                Calendar cal = Calendar.getInstance();
                cal.setTime(getThisWeekMonday(date));
                cal.add(Calendar.DATE, 7);
                return cal.getTime();
            }

            //获得今天日期
            public static Date getToday(){
                return new Date();
            }

            //获得本月一日的日期
            public static Date getFirstDay4ThisMonth(){
                Calendar calendar = Calendar.getInstance();
                calendar.set(Calendar.DAY_OF_MONTH,1);
                return calendar.getTime();
            }

            //获得本月最后一日的日期
            public static Date getLastDay4ThisMonth(){
                Calendar calendar = Calendar.getInstance();
                calendar.add(Calendar.MONTH, 1);
                calendar.set(Calendar.DAY_OF_MONTH, 0);
                return calendar.getTime();
            }

            public static void main(String[] args) {
                try {
                    System.out.println("本周一" + parseDate2String(getThisWeekMonday()));
                    System.out.println("本月一日" + parseDate2String(getFirstDay4ThisMonth()));
                } catch (Exception e) {
                    e.printStackTrace();
                }
            }
        }
        
    3.Jedis工具类：
        import redis.clients.jedis.Jedis;
        import redis.clients.jedis.JedisPool;
        import redis.clients.jedis.JedisPoolConfig;

        /**
         * ToDo
         *
         * @author Lyle
         * @date 2019/12/25
         */
        public class JedisUtils {
            //创建全局变量以便静态代码块中可以使用
            private static JedisPoolConfig jedisPoolConfig;
            private static JedisPool jedisPool;

            static {

                //因为JedisPool只需要创建和配置一次,所以放入静态代码块比较好
                jedisPoolConfig = new JedisPoolConfig();
                jedisPoolConfig.setMaxTotal(10);    //最多连接数量
                jedisPoolConfig.setMaxWaitMillis(1000); //等待时间
                // 2. 创建JedisPool对象
                String host = "127.0.0.1";
                int port = 6379;
                jedisPool = new JedisPool(jedisPoolConfig, host, port);
            }
            //对外提供get方法获得jedis,静态方法,类名调用比较好
            public static Jedis getJedis(){
                // 3. 从JedisPool获得jedis
                Jedis jedis = jedisPool.getResource();
                return jedis;

            }
            //释放资源
            public static void close(Jedis jedis){
                if(jedis != null){
                    jedis.close();
                }
            }


        }