java比较String类型日期的大小

工具类代码

1. 工具类

import java.text.DateFormat;
import java.text.NumberFormat;
import java.text.ParseException;
import java.text.SimpleDateFormat;
import java.util.*;

public class DateUtils {
 /**
     * 字符串转换为日期
     * @param s
     * @return
     * @throws ParseException
     */
    public static Date stringToDate(String s)  {
        String format ="yyyy-MM-dd";
        try{
            return new SimpleDateFormat(format).parse(s);
        }catch (ParseException e){
            e.printStackTrace();
            return null;
        }
    }

    /**
     * 字符串转换为日期时间
     * @param s
     * @return
     * @throws ParseException
     */
    public static Date stringToDateTime(String s)  {
        String format ="yyyy-MM-dd HH:mm:ss";
        try{
            return new SimpleDateFormat(format).parse(s);
        }catch (ParseException e){
            e.printStackTrace();
            return null;
        }
    }
}

功能实现

1. 方式一

public void compareDate(String date1,String date2){
		try {
			Date d1 = DateUtils.stringToDate(date1);
			Date d2 = DateUtils.stringToDate(date2);
			if(d1.equals(d2)){
				System.out.println(date1+"="+date2);
			}else if(d1.before(d2)){
				System.out.println(date1+"在"+date2+"之前");
			}else if(d1.after(d2)){
				System.out.println(date1+"在"+date2+"之后");
			}
		} catch (ParseException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
			System.out.println("compareDate（{}，{}）异常"+date1+","+date2);
		}
	}

2. 方式二

public void compateDate2(String date1,String date2){
		try {
			Date d1 = DateUtils.stringToDate(date1);
			Date d2 = DateUtils.stringToDate(date2);
			if(d1.getTime()>d2.getTime()){
				System.out.println(date1+"在"+date2+"之后");
			}else if(d1.getTime()<d2.getTime()){
				System.out.println(date1+"在"+date2+"之前");
			}else{
				System.out.println(date1+"="+date2);
			}
		} catch (ParseException e) {
			System.out.println("compateDate2（{}，{}）异常"+date1+","+date2);
			e.printStackTrace();
		}
	}