java中setDate(Date date)方法和String与Date之间的转换

经常在开发的过程中遇到这样的问题，从数据库中读出来的数据需要转换为对像或者java bean，此时经常使用到setDate(Date date);这样的方法。感觉这是个很简单而又难受的事情，在这里浪费时间真的是不应该。我这里就记录下我使用过的，方便以后查阅使用。

例如下面的setter方法：

    private String userId;
    private boolean isLogin;
    private Date loginTime;

    public void setLoginTime(Date loginTime) {
        Date oldLoginTime = this.loginTime;
        this.loginTime = loginTime;
    }
    public void setIsLogin(boolean isLogin) {
        boolean oldIsLogin = this.isLogin;
        this.isLogin = isLogin;
    }
    public void setUserId(String userId) {
        String oldUserId = this.userId;
        this.userId = userId;
    }

使用到的String转换为date方法

import java.sql.Timestamp;
import java.text.DateFormat;
import java.text.ParseException;
import java.text.SimpleDateFormat;

import java.util.Calendar;
import java.util.Date;

public class DateUtil {
    /**
     * set方法中是timestamp类型
     * new Timestamp(s)
     * @return s
     */
    public Timestamp newStampTime(){
        long s=System.currentTimeMillis();
        return new Timestamp(s);
    }
    /**
     * timeStamp转换为String
     * @return
     */
    public String timeStampToString(){
        SimpleDateFormat df = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");//定义格式，不显示毫秒
        Timestamp now = new Timestamp(System.currentTimeMillis());//获取系统当前时间
        String str = df.format(now);
        return str;
    }
    /**
     * String 转换为timestamp
     * @return
     */
    public Timestamp StringTotimeStamp(){
        SimpleDateFormat df = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
        String time = df.format(new Date());
        Timestamp ts = Timestamp.valueOf(time);
        return ts;
    }
    public Date myStringTotimeStamp(String dateString){
        int length=dateString.length();
        if(length>10){
            DateFormat df = new SimpleDateFormat("yyyy-MM-dd");
            Date today=new Date();
            try {
                today = df.parse("2009-11-11");
                //String ts=df.format(today);
            } catch (ParseException e) {
                e.printStackTrace();
            }
            return today;
        }else {
            DateFormat df = new SimpleDateFormat("yyyy-MM-dd");
            Date today=new Date();
            try {
                today = df.parse("2009-11-11");
                //String ts=df.format(today);
            } catch (ParseException e) {
                e.printStackTrace();
            }
            return today;
        }

    }
    /**
           * String 转换为timestamp
           * String "2016-5-25" 转换为 Timestamp
           * @return
           */
          public Timestamp StringTotimeStamp(String dateString){
                  SimpleDateFormat df = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
                  StringBuffer ds=new StringBuffer(dateString);
                  if(dateString.length()>10){
                          Timestamp ts = Timestamp.valueOf(dateString);
                          return ts;
                  }else{
                          ds.append(" 00:00:00");
                          Timestamp ts = Timestamp.valueOf(ds.toString());
                          return ts;
                  }
          }
    /**
     * 获取当前时间字符串
     * eg:2016-10-11 16:57:52
     **/
    public String formateDateString(){
        SimpleDateFormat format = new SimpleDateFormat("yyyy-MM-dd H:m:s");
        String dateString=format.format(new Date());
        return dateString;
    }
    /**
     * 指定时间和当前时间比较大小
     */
    public boolean compareTime(String t1){
        if(t1.length()<=10){
            t1=t1+" 23:59:59";
        }
        Date currentTime = new Date();// 当前时间
                SimpleDateFormat formatter = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
                String nowtime = formatter.format(currentTime);

                Calendar now = Calendar.getInstance();
                Calendar c1 = Calendar.getInstance();
                //String t1 = "2016-02-29 00:30:00";
                try {
                now.setTime(formatter.parse(nowtime));
                c1.setTime(formatter.parse(t1));
                } catch (ParseException e) {
                e.printStackTrace();
                }
                int result1 = now.compareTo(c1);// 比开始时间小，未开始
                System.out.println("结果:"+result1);
                if(result1>0){
                    return false;
                }else{
                    return true;
                }
    }      

}