java中setDate(Date date)方法和String與Date之間的轉換

常常在開發的過程當中遇到這樣的問題，從數據庫中讀出來的數據須要轉換爲對像或者java bean，此時常用到setDate(Date date);這樣的方法。感受這是個很簡單而又難受的事情，在這裏浪費時間真的是不該該。我這裏就記錄下我使用過的，方便之後查閱使用。

例以下面的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轉換爲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類型
     * new Timestamp(s)
     * @return s
     */
    public Timestamp newStampTime(){
        long s=System.currentTimeMillis();
        return new Timestamp(s);
    }
    /**
     * timeStamp轉換爲String
     * @return
     */
    public String timeStampToString(){
        SimpleDateFormat df = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");//定義格式，不顯示毫秒 
        Timestamp now = new Timestamp(System.currentTimeMillis());//獲取系統當前時間 
        String str = df.format(now);
        return str;
    }
    /**
     * String 轉換爲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 轉換爲timestamp
           * String "2016-5-25" 轉換爲 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;
                  }
          }
    /**
     * 獲取當前時間字符串
     * 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;
    }
    /**
     * 指定時間和當前時間比較大小
     */
    public boolean compareTime(String t1){
        if(t1.length()<=10){
            t1=t1+" 23:59:59";
        }
        Date currentTime = new Date();// 當前時間
                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);// 比開始時間小，未開始   
                System.out.println("結果:"+result1);
                if(result1>0){
                    return false;
                }else{
                    return true;
                }           
    }      
    
}