解決java.sql.Timestamp丟失精度的問題

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java.sql.Timestamp丟失精度

Timestamp的構造函數Timestamp(long time) 會丟失納秒部分的精度

需要重新補償

        Timestamp t1 = Timestamp.valueOf("2019-12-13 15:19:53.2202080");        
        Timestamp t2 = new Timestamp(1576250393220208000L / 1000000L);
        t2.setNanos((int) (1576250393220208000L % 1000000000L));

java.sql.Timestamp類的使用

Timestamp 可以精確到小數秒 一般存儲的格式：2016-12-18 11:05:36.531

Timestamp 可以獲取當前時間，也可以把字符串裝換成Timestamp類型

1. 獲取當前時間

@Test
public void getCurrentTime(){
	//第一種
	Date date = new Date();
	Timestamp currentTime1 = new Timestamp(date.getTime());
	System.out.println("currentTime1:"+currentTime1);
	//第二種
	Timestamp currentTime2 = new Timestamp(System.currentTimeMillis());
	System.out.println("currentTime2:"+currentTime2);
}

2.String類型轉換為Timestamp

@Test
public void stringConvertTimestamp(){
	String timeStr = "2016-12-18 11:16:33.706";
	Timestamp ts = Timestamp.valueOf(timeStr);
	System.out.println(ts);
}

3.Timestamp轉換為String類型

@Test
public void timestampConvertString(){
	SimpleDateFormat sdf = new SimpleDateFormat("yyy-MM-dd HH:mm:ss");
	Timestamp currentTime = new Timestamp(System.currentTimeMillis());
	String timeStr = sdf.format(currentTime);
	System.out.println(timeStr);
}

整個演示類的代碼：

package com.demo; 
import java.sql.Timestamp;
import java.text.SimpleDateFormat;
import java.util.Date; 
import org.junit.Test; 
public class DemoTimestamp {
	@Test
	public void getCurrentTime(){
		//第一種
		Date date = new Date();
		Timestamp currentTime1 = new Timestamp(date.getTime());
		System.out.println("currentTime1:"+currentTime1);
		//第二種
		Timestamp currentTime2 = new Timestamp(System.currentTimeMillis());
		System.out.println("currentTime2:"+currentTime2);
	}
	@Test
	public void stringConvertTimestamp(){
		String timeStr = "2016-12-18 11:16:33.706";
		Timestamp ts = Timestamp.valueOf(timeStr);
		System.out.println(ts);
	}
	@Test
	public void timestampConvertString(){
		SimpleDateFormat sdf = new SimpleDateFormat("yyy-MM-dd HH:mm:ss");
		Timestamp currentTime = new Timestamp(System.currentTimeMillis());
		String timeStr = sdf.format(currentTime);
		System.out.println(timeStr);
	}
}

以上為個人經驗，希望能給大傢一個參考，也希望大傢多多支持WalkonNet。

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