我把一些测试JDBC代码放在一起,以确定究竟发生了什么.结果很有趣. Oracle有三种密切相关的数据类型：TIMESTAMP,TIMESTAMP WITH TIME ZONE和TIMESTAMP WITH LOCAL TIME ZONE.我使用完全相同的代码,从两个不同的框中运行它,一个在“America / New_York”时区,一个在UTC上运行.两者都以UTC格式运行相同的数据库.我使用的是Oracle 11.2.0.2.0驱动程序.

> TIMESTAMP列设置为执行Java代码的机器上的本地时间.没有执行时区转换.
> TIMESTAMP WITH TIME ZONE列将时间转换为JDBC客户端所在的任何时区.
> TIMESTAMP WITH LOCAL TIME ZONE列还将时间转换为JDBC客户端所在的任何时区.

This article,它有点旧,表示如果你想做索引或分区之类的事情,TIMESTAMP WITH TIME ZONE几乎没用.但是,似乎TIMESTAMP WITH LOCAL TIME ZONE可能非常有用. (不确定如果更改服务器的时区会发生什么,但它似乎对JDBC客户端的本地时区是智能的).我没有机会使用这些数据类型测试索引行为等.

如果您想在您的环境中重现我的测试,请在下面的示例类中粘贴.

import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.Timestamp;
import java.util.Date;

// create table x_tst_ts_tab(
// os_name varchar(256)
// ts timestamp,// ts_with_tz timestamp with time zone,// ts_with_local_tz timestamp with local time zone
// )
class TSTest {
    public static final void main(String[] argv) throws Exception {
        Class.forName("oracle.jdbc.OracleDriver");
        Connection conn = DriverManager.getConnection(
            "your_connection_string","your_user_name","your_password");

        try {
            // Insert some data
            Date nowDate = new Date();
            Timestamp nowTimestamp = new Timestamp(nowDate.getTime());
            PreparedStatement insertStmt = conn.prepareStatement(
                "INSERT INTO x_tst_ts_tab"
                + " (os_name,ts,ts_with_tz,ts_with_local_tz)"
                + " VALUES (?,?,?)");
            try {
                insertStmt.setString(1,System.getProperty("os.name"));
                insertStmt.setTimestamp(2,nowTimestamp);
                insertStmt.setTimestamp(3,nowTimestamp);
                insertStmt.setTimestamp(4,nowTimestamp);
                insertStmt.executeUpdate();
            } finally {
                try {
                    insertStmt.close();
                } catch (Throwable t) {
                    // do nothing
                }
            }

            System.out.println("os_name,ts_with_local_tz");

            // Read back everything in the DB
            PreparedStatement selectStmt = conn.prepareStatement(
                "SELECT os_name,ts_with_local_tz"
                + " FROM dom_fraud_beacon.x_tst_ts_tab");
            ResultSet result = null;
            try {
                result = selectStmt.executeQuery();
                while (result.next()) {
                    System.out.println(
                        String.format("%s,%s,%s",result.getString(1),result.getTimestamp(2).toString(),result.getTimestamp(3).toString(),result.getTimestamp(4).toString()
                                      ));
                }
            } finally {
                try {
                    result.close();
                } catch (Throwable t) {
                    // do nothing
                } finally {
                    try {
                        selectStmt.close();
                    } catch (Throwable t) {
                        // do nothing
                    }
                }
            }
        } finally {
            try {
                conn.close();
            } catch (Throwable t) {
                // do nothing
            }
        }
    }
}