java 操作日期的util,日期工具类,Calender

import java.text.ParseException;
import java.text.SimpleDateFormat;
import java.util.Calendar;
import java.util.Date;

import org.apache.commons.lang.StringUtils;

/**
 * 查询范围时间 JavaBean
 *
 * @since 2009-1-6 下午08:07:59
 */
public class DateQuery {
    
    /**
     * 用于起始时间
     */
    private Date fromDate;
    
    /**
     * 用于结束时间
     */
    private Date toDate;
    
    /**
     * 起始时间的字符串形式
     */
    private String fromDateStr;
    
    /**
     * 结束时间的字符串形式
     */
    private String toDateStr;
    
    private SimpleDateFormat sdf = null;
    
    private boolean isMonth = false;
    
    public DateQuery() {
        this(false);
    }
    
    public DateQuery(boolean isMonth) {
        this.isMonth = isMonth;
        if(isMonth) {
            // 记录年和月（用于月查询）
            sdf = new SimpleDateFormat("yyyy-MM");
        } else {
            // 记录年月日（用于日期查询）
            sdf = new SimpleDateFormat("yyyy-MM-dd");
        }
    }
    
    public Date getFromDate() {
        if(this.fromDate == null && StringUtils.isNotEmpty(this.fromDateStr)) {
            this.fromDate = parse(this.fromDateStr);
        }
        return this.fromDate;
    }
    
    public void setFromDate(Date fromDate) {
        this.fromDate = fromDate;
        if(fromDate != null) {
            this.fromDateStr = sdf.format(fromDate);
        } else {
            this.fromDateStr = null;
        }
    }
    
    public Date getToDate() {
        if(this.toDate == null && StringUtils.isNotEmpty(this.toDateStr)) {
            this.toDate = parse(this.toDateStr);
        }
        return toDate;        
    }
    
    public void setToDate(Date toDate) {
        this.toDate = toDate;
        if(toDate != null) {
            this.toDateStr = format(this.toDate);
        } else {
            this.toDateStr = null;
        }
    }
    
    public String getFromDateStr() {
        if(StringUtils.isNotEmpty(this.fromDateStr) && this.fromDate != null) {
            this.fromDateStr = format(this.fromDate);
        }
        return this.fromDateStr;
    }
    
    public void setFromDateStr(String fromDateStr) {
        this.fromDateStr = fromDateStr;
        if(fromDateStr != null) {
            this.fromDate = parse(fromDateStr);
        }
    }
    
    public String getToDateStr() {
        if(StringUtils.isNotEmpty(this.toDateStr) && this.toDate != null) {
            this.toDateStr = format(this.toDate);
        }
        return toDateStr;
    }
    
    public void setToDateStr(String toDateStr) {
        this.toDateStr = toDateStr;
        if(toDateStr != null) {
            this.toDate = parse(toDateStr);
        }
    }
    
    /**
     * 获得结束时间的下一天或者下一月，用于查询条件中
     * @return
     *
     * @since 2009-1-6 下午08:09:54
     */
    public Date getNextToDate() {
        Date date = getToDate();
        if(date == null) {
            return null;
        }
        Calendar c = Calendar.getInstance();
        c.setTime(date);
        int add = isMonth ? Calendar.MONTH : Calendar.DATE;
        c.add(add, 1);
        return c.getTime();
    }
    
    /**
     * 将字符串转为 Date
     * @param str
     * @return
     *
     * @since 2009-1-6 下午08:10:15
     */
    private Date parse(String str) {
        Date date = null;
        try {
            date = sdf.parse(str);
        } catch (ParseException e) {
            e.printStackTrace();
        }
        return date;
    }
    
    /**
     * 格式化字符串
     * @param date
     * @return
     *
     * @since 2009-1-6 下午08:10:25
     */
    private String format(Date date) {
        return sdf.format(date);
    }
}

import org.apache.commons.lang.StringUtils;的包在附件中下载
包名是:commons-lang-2.6.jar(或者会有更新的版本)

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