Date/time handling techniques in JDBC

1. For different types of time of the database, the corresponding Java wrapper classes should be used to access them respectively; Date type with java.sql.Date, Time type with java.sql.Time, date/time type with Java.sql.Timestamp; Here's an example: assuming that you want to get the system time from Oracle, you need to perform sql:select sysdate from dual, Then, when you get the query results through resultset, be sure to call the method: Gettimestamp (), so that you can take the month and a minute to get out, The call to GETDATE () can only be taken out of the month-day, call GetTime () can only be retrieved seconds. 2. Try not to call GetString () to obtain date/time type data; Calling GetString () can also fetch data of the time type, and JDBC converts the date/time to a string internally; But the format of this string depends on the database, Oracle is a kind of, with Sybase is a, MySQL is a kind of, If you want to be compatible with a variety of databases, or do not use GetString () good. 3. How to convert the date/time type of JDBC to a string; Have ever seen someone write this: Java.sql.Timestamp Timestamp =//Get this data through database access Java.util.Date utildate = new Java.util.Date (Timestamp.gettime ()); SimpleDateFormat SDF = new SimpleDateFormat ("Yyyy-mm-dd HH:mm:ss"); String str = Sdf.format (utildate); This can also achieve the ultimate goal, but there is a problem, Java.sql.Timestamp is inherited Java.util.Date, Therefore, it is not necessary to temporarily create a utildate when format is passed directly into the timestamp. Just like the following: Java.sql.Timestamp Timestamp =//Get this data through database access SimpleDateFormat SDF = new SimpleDateFormat ("Yyyy-mm-dd HH:mm:ss"); String str = Sdf.format (timeStamp); 4. When making a SELECT, update, or INSERT, If a field is a date/time type, it is best to use PreparedStatement instead of the statement You will often see a program like this: Connection conn;//the preceding steps slightly Statement stmt = Conn.createstatement (); Stmt.execute ("INSERT into tab (begin_date) VALUES (to_date (' 06/27/2005 12:59:52 ', ' mm/dd/yyyy HH24:MI:SS ')"); People familiar with Oracle know that To_date is a function in Oracle, and that other databases are not, if any, likely to be different. So this code can only be used on Oracle, If you change to another database, the program cannot be executed. If you use PreparedStatement, the code is like this: Connection conn;//the preceding steps slightly PreparedStatement pstmt = conn.preparestatement ("INSERT into tab (Begin_date) VALUES (?)"); Pstmt.settimestamp (1, New Timestamp (System.currenttimemillis ())); Pstmt.execute (); As you can see, this code has nothing to do with the database, as long as it is a database that supports standard SQL. 5.java.sql.timestamp how to convert to Java.util.Date Java.sql.Timestamp is a subclass of Java.util.Date that does not require any conversion to be directly assigned: Java.sql.Timestamp ts; Java.util.Date utildate; utildate = ts; 6.java.util.date how to convert to Java.sql.Timestamp Java.util.Date is Java.sql.Timestamp's parent class and cannot be done like trick 5. To do this: Java.sql.Timestamp ts; Java.util.Date utildate; Ts.settime (Utildate.gettime ());