Summary of JDBC Connection database code and procedures in "Go" Java development

(Transferred from:http://www.cnblogs.com/hongten/archive/2011/03/29/1998311.html)

JDBC Connection Database

Create a program that connects to the database in JDBC with 7 steps:

1. Load the JDBC driver:

Before connecting to a database, you first load the driver of the database you want to connect to the JVM (Java Virtual machine), which is implemented by the static method forname (String className) of the Java.lang.Class class.
For example:

Try {     //    class.forname ("Com.mysql.jdbc.Driver");} Catch (ClassNotFoundException e) {     System.out.println ("Driver class not found, load driver failed!") ");     

After a successful load, an instance of the driver class is registered in the DriverManager class.

2. Provide the URL of the JDBC connection

• The connection URL defines the protocol, sub-protocol, and data source identity when the database is connected.
• Written form: protocol: Sub-Protocol: Data source identification
Protocol: Always start with JDBC in JDBC
Sub-Protocol: A bridge-connected driver or database management system name.
Data source identification: The tag locates the address of the database source and the connection port.
For example: (MySQL connection URL)

jdbc:mysql://localhost:3306/test?useunicode=true&characterencoding=gbk;

Useunicode=true: Indicates the use of the Unicode character set. If Characterencoding is set to gb2312 or GBK, this parameter must be set to true. CHARACTERENCODING=GBK: The character encoding method.

3. Create a connection to the database

To connect to a database, you need to request and obtain a connection object from Java.sql.DriverManager, which represents a connection to a database.
The DriverManager getconnectin (string URL, string username, string password) method is used to pass in the path of the specified database to be connected, the user name of the database, and the password to obtain.
For example:

String url = "Jdbc:mysql://localhost:3306/test"= "root"= "root" Try    {     = drivermanager.getconnection (URL, username, password);} Catch (SQLException se) {     System.out.println ("Database connection failed! ");     

4. Create a statement

To execute the SQL statement, you must obtain the Java.sql.Statement instance, which is divided into the following 3 types of statement instances:
1. Execute static SQL statements. Typically implemented through statement instances.
2. Execute dynamic SQL statements. Typically implemented through PreparedStatement instances.
3. Execute the database stored procedure. Typically implemented through CallableStatement instances.
The specific implementation method:

Statement stmt ==

5. Execute SQL statements

The statement interface provides three ways to execute SQL statements: ExecuteQuery, executeupdate, and execute
1. ResultSet executeQuery (String sqlString): Executes the SQL statement that queries the database and returns a result set (ResultSet) object.
2, int executeupdate (String sqlString): Used to execute INSERT, UPDATE, or DELETE statements and SQL DDL statements such as CREATE table and drop table, etc.
3. Execute (sqlString): Used to execute statements that return multiple result sets, multiple update counts, or both.
Specific implementation code:

ResultSet rs = stmt.executequery ("SELECT * from ..."int rows = stmt.executeupdate ("INSERT into ..."   Boolean

6. Processing results

Two cases:
1. The number of records affected by this operation is returned by performing the update.
2. The result of executing the query returned is a ResultSet object.
ResultSet contains all rows that conform to the conditions in the SQL statement, and it provides access to the data in those rows through a set of Get methods.
Get data using the access method of the result set (ResultSet) object:

 while (Rs.next ()) {     = rs.getstring ("name");      //

(columns are numbered from left to right and start with column 1)

7. Close the JDBC Object

After the operation is complete, all the JDBC objects used are closed to release the JDBC resource, and the order of closing and declaration is reversed:
1. Close record set
2. Closing the statement
3. Close the Connection object

if(rs! =NULL) {//To close a record set    Try{rs.close (); }Catch(SQLException e) {e.printstacktrace (); } } if(stmt! =NULL) {//Close Declaration    Try{stmt.close (); }Catch(SQLException e) {e.printstacktrace (); } } if(Conn! =NULL){//Close the Connection object    Try{conn.close (); }Catch(SQLException e) {e.printstacktrace (); } } 

8. Complete Reference Code

Complete Java connection MySQL database code and steps can be viewed at the following address (more suitable for beginners):

Http://www.cnblogs.com/wuqianling/p/5380234.html

Summary of JDBC Connection database code and procedures in "Go" Java development