Article 6: Database Start

Serious warning: I haven't figured out the previous problems, please don't look down again.

Opening white: Originally, where should Ctrl V, a section of the JDBC's stuff, I think it is a bit too theory and dogma, so I don't quite more than Luo, but I still talk about two points, otherwise People who are as stupid as me really don't know what I wrote "people's code" or "machine code". So strong suggestions do not skip the following content.

Some basic steps for database programming:

Registration driver

Create a database connection

Execute SQL statement get the result

Some basic classes to use

CONNECTION Class

Statement class and PeparedStatement classes

Resultset class

Need to pay attention

When the database operation, it will appear, pay attention to capture and process.

Explanation with the following code

/ / Define the driver of the database (hereinafter given below is to connect the ODBC database)

String striver = "sun.jdbc.odbc.jdbcodbcdriver";

// Define the URL of the data (name)

String strconnection = "jdbc: odbc: myfirstdata";

// Username

String strconnectusername = "";

// Database Access password

String strconnectpassword = ""

Connection conn = NULL;

Statement Stmt = NULL;

ResultSet RS = NULL;

String SQL_TEMP = "SELECT * from TableName"

Try

{

Class.Forname (strDriver); // Register driver

}

Catch (ClassNotFoundException EX1)

{

EX1.PRINTSTACKTRACE (); // Capture the exception during the driver registration process

}

Try

{

Conn = // Get database connections

Drivermanager.getConnection (STRCONNECTION,

StrConnectusername,

StrConnectPassword;

Stmt = conn.createstatement (); // Create a StMT of StMT

RS = stmt.executeQuery (SQL_TEMP); // Execute SQL operations with STMT to return to RS

}

Catch (SQLEXCEPTION EX2)

{

EX2.PRINTSTACKTRACE ();

}

Come an example to explain how?

Function description

Write a user login program, enter the password, click the "Login" button, find it in the user data sheet, if there is a corresponding record, tell: Hello, welcome you! If there is no user, it will be prompted: the username or password is incorrect, please re-login.

Wow, I finally went to write a little person to touch the dog-like program. I used to call the procedure before, it is simply the name of the three-structure. . .

Create a database: In order to simply use Access to build one, the name of the database is User, set it in ODBC. What, don't know how to set it? Oh, I really don't have a mood to explain with you. Please solve this problem and look down.

Create a data table: useertable

User number Userno text

User password Password text location department number departno text

Fill in a few values

111 111 001

222 222 002

333 333 003

JSP on the landing (I am afraid I will tell you how to write this kind of JSP)

Login.jsp

<% @ Page ContentType = "text / html; charset = GB2312"%>

<% @ Taglib Uri = "/ Web-INF / STRUTS-TILES.TLD" prefix = "tiles"%>

<% @ Taglib URI = "/ Web-INF / STRUTS-HTML.TLD" prefix = "html"%>

<% @ Taglib URI = "/ Web-INF / STRUTS-LOGIC.TLD" prefix = "logic"%>

<% @ Taglib Uri = "/ Web-INF / STRUTS-Bean.tld" prefix = "bean"%>