Question

当我尝试使用sqlite3查询通过JDBC插入的日期时，我看到了意外的结果。这个java代码：

try (Connection conn = DriverManager.getConnection("jdbc:sqlite:test.db")) {
    conn.setAutoCommit(true);
    try (Statement statement = conn.createStatement()) {
        statement.executeUpdate("create table dates (date DATETIME);");
    }

    try (PreparedStatement insert = conn
            .prepareStatement("insert into dates values (?)")) {
        insert.setTimestamp(1, Timestamp.valueOf(LocalDateTime.now()));
        insert.executeUpdate();
    }
}

似乎没有插入正确的日期时间 - 当我通过sqlite3查询时，我无法获得人类可读的值：

sqlite3 test.db "select date, datetime(date, 'unixepoch') from dates;"
1507819362296|

这是有道理的，因为sqlite文档说有效的unix纪元范围是＆＃34; -62167219200到106751991167＆＃34; （https://sqlite.org/lang_datefunc.html）。

我应该如何在JDBC和Sqlite中使用日期？

Answer 1

SQLite中没有正式的日期或时间戳类型，而是由字符串表示。因此，如果您想将当前时间戳插入表中，可以尝试以下操作：

try (Connection conn = DriverManager.getConnection("jdbc:sqlite:test.db")) {
    conn.setAutoCommit(true);
    try (Statement statement = conn.createStatement()) {
        statement.executeUpdate("CREATE TABLE dates (date TEXT);");
    }

    SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
    Timestamp timestamp = new Timestamp(System.currentTimeMillis());
    String ts = sdf.format(timestamp);

    try (PreparedStatement ps = conn
            .prepareStatement("INSERT INTO dates (date) VALUES (?)")) {
        ps.setString(1, ts);
        ps.executeUpdate();
    }
}

Answer 2

@Mark W我们一直把sqlite数据库中的日期作为字符串放入，但它们看起来不像10-18-2017这样的字符串就像10182017那样，并且它们都是8个字符长。但当你把它们拉出来时，他们会全身心地打扮起来并转变回到这个10-18-2017。我们已经测试了我们的搜索，并且所有搜索似乎都按照需要使用SELECT * FROM TABLE_NAME WHERE Col_Date＆gt; =＆＃34;来自＆＃34; AND Col_Date＆lt; =＆＃34; to＆＃34;下面是使日期不那么漂亮的代码

    public void findByDate(View view){
    use= false;
    // custom dialog /* THIS R.style.DatePickerThem is mandatory to use res/values/styles */
    final Dialog dialog = new Dialog(MainActivity.this,R.style.DatePickerTheme);
    dialog.setContentView(R.layout.datepickerview);
    dialog.setTitle("");
    DatePicker picker = dialog.findViewById(R.id.datePicker);
    final Calendar c = Calendar.getInstance();
    mYear = c.get(Calendar.YEAR);
    mMonth = c.get(Calendar.MONTH);
    mDay = c.get(Calendar.DAY_OF_MONTH);
    //picker.updateDate(2017, 10, 13);//year month day
    picker.updateDate(mYear, mMonth, mDay);// Keeps Calendar initial view what ever today is!

    System.out.println("Month " + mMonth+1);

    picker.init(c.get(Calendar.YEAR), c.get(Calendar.MONTH), c.get(Calendar.DAY_OF_MONTH), new DatePicker.OnDateChangedListener() {
        //picker.init(Integer.valueOf(mMonth),Integer.valueOf(mDay),Integer.valueOf(mYear), new DatePicker.OnDateChangedListener() {
        @Override
        public void onDateChanged(DatePicker picker, int year, int monthOfYear, int dayOfMonth) {

            if (etFromDate.getText().toString().isEmpty()) {
                System.out.println("I am Not Empty");

                //etFromDate.setText(String.valueOf(monthOfYear+1 ) + String.valueOf(dayOfMonth) + String.valueOf(year));
                //v1 = Long.valueOf(etFromDate.getText().toString());
                //etFromDate.setText(String.valueOf(v1));
                //String theDATE = (monthOfYear+1) + "-" + (dayOfMonth) + "-" + (year);
                String searchFrom = (String.valueOf(monthOfYear+1))+(String.valueOf(dayOfMonth))+String.valueOf(year);
                if(searchFrom.length()==7){
                    StringBuilder str = new StringBuilder(searchFrom);
                    str.insert(2, '0');
                    etFromDate.setText(str);
                }else if (searchFrom.length() == 6){
                    StringBuilder str = new StringBuilder(searchFrom);
                    str.insert(0,'0');
                    str.insert(2,'0');
                    etFromDate.setText(str);
                }else {
                    etFromDate.setText(searchFrom);
                }


                //setDATE = etFromDate.getText().toString();
                dialog.dismiss();

然后，这里有一种方法可以将同一个字符串10182017视为一个高级时装日期

        helper = new DBHelper(this);
    dbList = new ArrayList<>();
    dbList = helper.getDataFromDB();

    if (dbList.size() > 0 && tORf.equalsIgnoreCase("false")) {

        btnSave.setVisibility(View.INVISIBLE);
        String NVrowid = String.valueOf(dbList.get(position).getRowid());
        String NVstation = dbList.get(position).getStation_Name();
        String NVpurchasedate = dbList.get(position).getDate_of_Purchase();
        String s = NVpurchasedate;
        String month = s.substring(0, 2);
        String day = s.substring(2, 4);
        String year = s.substring(4, 8);
        String date3 = month + "-" + day + "-" + year;
        String NVcost = dbList.get(position).getGas_Cost();
        etStation.setText(NVstation);
        etPurchaseDate.setText(date3);
        //etPurchaseDate.setText(NVpurchasedate);
        etCost.setText(NVcost);
    }

从Java中将日期时间插入sqlite的正确方法是什么？

2 个答案: