Java工具类

/**
 * 工具类
 * 取时间的各种算法（Date,String）
 * 时间计算方法（加减/毫秒）
 * @author SLG
 *
 */
public class DateTools {

    private static final Logger logger = Logger.getLogger(DateTools.class);


    /**
     * 将时间格式(Date)转换为时间字符串 yyyy-MM-dd HH:mm:ss(String)
     * Date-->String
     * 当前时间可传入new Date()
     * @param dateDate
     * @return
     */
    public static String dateToStr(Date dateDate){
        SimpleDateFormat format = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
        String dateString = format.format(dateDate);
        return dateString;
    }

    /**
     * 将短时间格式字符串（String）转换为时间 yyyy-MM-dd HH:mm:ss(Date)
     * String-->Date
     * @param strDate
     * @return 如Sat Jun 17 13:20:59 CST 2017
     * @throws Exception
     */
    public static Date strToDate(String strDate){
        SimpleDateFormat format = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
        try {
            //解析此类数据：2001-12-17T09:30:47.0Z
            if(strDate == null || "".equals(strDate)){
                return new Date();
            }
            if(strDate.contains("T")){
                strDate = strDate.replace("T", " ").substring(0,19);
            }
            Date strtodate = format.parse(strDate);
            return strtodate;
        } catch (Exception e) {
            logger.error("Input strDate:"+strDate);
        }
        return null;
    }

    /**
     * 将格式正确的时间字符串输出成固定格式的字符串(时:分:秒)
     * @param str
     * @return
     * @throws Exception
     */
    public static String strToStrDay(String str) throws Exception{
        SimpleDateFormat sdf = new SimpleDateFormat("HH:mm:ss");
        String dateString = sdf.format(strToDate(str));
        return dateString;
    }

    /**
     * 将格式正确的时间输出成固定格式的字符串(时:分:秒)
     * @param date
     * @return
     * @throws Exception
     */
    public static String strToStrDay(Date date) throws Exception{
        SimpleDateFormat sdf = new SimpleDateFormat("HH:mm:ss");
        String dateString = sdf.format(date);
        return dateString;
    }

    /**
     * 将格式正确的时间字符串输出成固定格式的字符串(年/月/日)
     * @param str
     * @return
     * @throws Exception
     */
    public static String strToDay(String str) throws Exception{
        SimpleDateFormat sdf = new SimpleDateFormat("yyyy/MM/dd");
        String dateString = sdf.format(strToDate(str));
        return dateString;
    }

    /**
     * 将格式正确的时间输出成固定格式的字符串(年/月/日)
     * @param date
     * @return
     * @throws Exception
     */
    public static String strToDay(Date date) throws Exception{
        SimpleDateFormat sdf = new SimpleDateFormat("yyyy/MM/dd");
        String dateString = sdf.format(date);
        return dateString;
    }

    /**
     * 将格式正确的时间输出成固定格式的字符串(年月日)
     * @param date
     * @return
     * @throws Exception
     */
    public static String strToDayAll(Date date){
        SimpleDateFormat sdf = new SimpleDateFormat("yyyyMMdd");
        String dateString = sdf.format(date);
        return dateString;
    }

    /**
     * 将格式正确的时间输出成固定格式的字符串(年月日)
     * @param date
     * @return
     * @throws Exception
     */
    public static String strToTime(Date date){
        SimpleDateFormat sdf = new SimpleDateFormat("HHmmss");
        String dateString = sdf.format(date);
        return dateString;
    }

    /**
     * 将时间生成字符串(用于生成路径)
     * @param string
     * @return
     */
    public static String DateToStrToRoute(String string){
        String str = string.replaceAll("-", "");
        str = str.replaceAll(" ","");
        str = str.replaceAll(":","");
        return str;
    }
    public static String YesterDay(){
        Calendar calendar1 = Calendar.getInstance();
        calendar1.set(calendar1.get(Calendar.YEAR), calendar1.get(Calendar.MONTH), calendar1.get(Calendar.DAY_OF_MONTH),
                0, 0, 0);
        Date beginOfDate = calendar1.getTime();
        return dateToStr(beginOfDate);
    }
    public static void main(String[] args) throws Exception{
        System.out.print(YesterDay());
    }
}