时间迭代和BigDecimal操作详解编程语言

import java.math.BigDecimal; 
import java.sql.Timestamp; 
import java.text.SimpleDateFormat; 
import java.util.ArrayList; 
import java.util.Calendar; 
import java.util.Date; 
import java.util.Iterator; 
 
public class TestCommon { 
    private static SimpleDateFormat df = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss"); 
     
    public static void main(String[] args) {     
        System.out.println("===时间操作==="); 
        long times= 1471253315716l ; 
        Timestamp ts =new Timestamp(times); 
        System.out.println(df.format(ts)); 
         
        Calendar calendar = Calendar.getInstance(); 
        calendar.setTime(new Date()); 
        calendar.set(Calendar.DAY_OF_MONTH, calendar.get(Calendar.DAY_OF_MONTH)-30); 
        System.out.println("---"+df.format(calendar.getTime())); 
         
        System.out.println("===运算操作==="); 
        BigDecimal big1 = new BigDecimal(654); 
        BigDecimal big2 = new BigDecimal("354.254788"); 
        //big1.compareTo(big2) = 0  
        System.out.println((big1.add(big2)).setScale(2,BigDecimal.ROUND_HALF_UP));         
        System.out.println(big1.divide(new BigDecimal(2), 2,BigDecimal.ROUND_HALF_UP)); 
         
        System.out.println("===迭代操作==="); 
        Iterable<BigDecimal> values= new ArrayList<>(); 
        BigDecimal sum = new BigDecimal(0); 
        for (Iterator iter = values.iterator(); iter.hasNext();) { 
            BigDecimal val = (BigDecimal)iter.next(); 
            sum = sum.add(val); 
        } 
    } 
}