java把13位时间戳转换成"yyyy-MM-dd HH:mm:ss"格式的工具类

package com.liming.test;


import java.sql.SQLException;
import java.text.SimpleDateFormat;
import java.util.Calendar;
import java.util.Date;
import java.util.HashMap;
import java.util.Map;

import org.junit.Test;
public class Test4 {
	@Test
	public void testConn() throws SQLException{
		String time = "1520423832415";
		String timeStamp2Date = timeStamp2Date(time);
		System.out.println(timeStamp2Date);
		
	}
	
	public static String timeStamp2Date(String time) {
	    Long timeLong = Long.parseLong(time);
	    SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");//要转换的时间格式
	    Date date;
	    try {
	        date = sdf.parse(sdf.format(timeLong));
	        return sdf.format(date);
	    } catch (Exception e) {
	        e.printStackTrace();
	        return null;
	    }
	} 
 
}