今天自己寫的一個用于取得當前日期相對應的月初，月末，季初，季末，年初，年末，返回值均為String字符串，方法比較土，使用字符串套接方法完成。

package com.zrar.date;

import java.util.Calendar;

/**
 *
 * 描述:此類用于取得當前日期相對應的月初，月末，季初，季末，年初，年末，返回值均為String字符串
 *      1、得到當前日期         today()
 *      2、得到當前月份月初      thisMonth()
 *      3、得到當前月份月底      thisMonthEnd()
 *      4、得到當前季度季初      thisSeason()
 *      5、得到當前季度季末      thisSeasonEnd()
 *      6、得到當前年份年初      thisYear()
 *      7、得到當前年份年底      thisYearEnd()
 *      8、判斷輸入年份是否為閏年 leapYear
 *     
 * 注意事項:  日期格式為：xxxx-yy-zz (eg: 2007-12-05)
 *
 * 實例:
 *
 * @author pure
 */
public class DateThis {

    private int x;                  // 日期屬性：年

    private int y;                  // 日期屬性：月

    private int z;                  // 日期屬性：日

    private Calendar localTime;     // 當前日期

    public DateThis() {
        localTime = Calendar.getInstance();
    }

    /**
     * 功能：得到當前日期 格式為：xxxx-yy-zz (eg: 2007-12-05)<br>
     * @return String
     * @author pure
     */
    public String today() {
        String strY = null;
        String strZ = null;
        x = localTime.get(Calendar.YEAR);
        y = localTime.get(Calendar.MONTH) + 1;
        z = localTime.get(Calendar.DATE);
        strY = y >= 10 ? String.valueOf(y) : ("0" + y);
        strZ = z >= 10 ? String.valueOf(z) : ("0" + z);
        return x + "-" + strY + "-" + strZ;
    }

    /**
     * 功能：得到當前月份月初 格式為：xxxx-yy-zz (eg: 2007-12-01)<br>
     * @return String
     * @author pure
     */
    public String thisMonth() {
        String strY = null;
        x = localTime.get(Calendar.YEAR);
        y = localTime.get(Calendar.MONTH) + 1;
        strY = y >= 10 ? String.valueOf(y) : ("0" + y);
        return x + "-" + strY + "-01";
    }

    /**
     * 功能：得到當前月份月底 格式為：xxxx-yy-zz (eg: 2007-12-31)<br>
     * @return String
     * @author pure
     */
    public String thisMonthEnd() {
        String strY = null;
        String strZ = null;
        boolean leap = false;
        x = localTime.get(Calendar.YEAR);
        y = localTime.get(Calendar.MONTH) + 1;
        if (y == 1 || y == 3 || y == 5 || y == 7 || y == 8 || y == 10 || y == 12) {
            strZ = "31";
        }
        if (y == 4 || y == 6 || y == 9 || y == 11) {
            strZ = "30";
        }
        if (y == 2) {
            leap = leapYear(x);
            if (leap) {
                strZ = "29";
            }
            else {
                strZ = "28";
            }
        }
        strY = y >= 10 ? String.valueOf(y) : ("0" + y);
        return x + "-" + strY + "-" + strZ;
    }

    /**
     * 功能：得到當前季度季初 格式為：xxxx-yy-zz (eg: 2007-10-01)<br>
     * @return String
     * @author pure
     */
    public String thisSeason() {
        String dateString = "";
        x = localTime.get(Calendar.YEAR);
        y = localTime.get(Calendar.MONTH) + 1;
        if (y >= 1 && y <= 3) {
            dateString = x + "-" + "01" + "-" + "01";
        }
        if (y >= 4 && y <= 6) {
            dateString = x + "-" + "04" + "-" + "01";
        }
        if (y >= 7 && y <= 9) {
            dateString = x + "-" + "07" + "-" + "01";
        }
        if (y >= 10 && y <= 12) {
            dateString = x + "-" + "10" + "-" + "01";
        }
        return dateString;
    }

    /**
     * 功能：得到當前季度季末 格式為：xxxx-yy-zz (eg: 2007-12-31)<br>
     * @return String
     * @author pure
     */
    public String thisSeasonEnd() {
        String dateString = "";
        x = localTime.get(Calendar.YEAR);
        y = localTime.get(Calendar.MONTH) + 1;
        if (y >= 1 && y <= 3) {
            dateString = x + "-" + "03" + "-" + "31";
        }
        if (y >= 4 && y <= 6) {
            dateString = x + "-" + "06" + "-" + "30";
        }
        if (y >= 7 && y <= 9) {
            dateString = x + "-" + "09" + "-" + "30";
        }
        if (y >= 10 && y <= 12) {
            dateString = x + "-" + "12" + "-" + "31";
        }
        return dateString;
    }

    /**
     * 功能：得到當前年份年初 格式為：xxxx-yy-zz (eg: 2007-01-01)<br>
     * @return String
     * @author pure
     */
    public String thisYear() {
        x = localTime.get(Calendar.YEAR);
        return x + "-01" + "-01";
    }

    /**
     * 功能：得到當前年份年底 格式為：xxxx-yy-zz (eg: 2007-12-31)<br>
     * @return String
     * @author pure
     */
    public String thisYearEnd() {
        x = localTime.get(Calendar.YEAR);
        return x + "-12" + "-31";
    }

    /**
     * 功能：判斷輸入年份是否為閏年<br>
     *
     * @param year
     * @return 是：true  否：false
     * @author pure
     */
    public boolean leapYear(int year) {
        boolean leap;
        if (year % 4 == 0) {
            if (year % 100 == 0) {
                if (year % 400 == 0) leap = true;
                else leap = false;
            }
            else leap = true;
        }
        else leap = false;
        return leap;
    }
}