Example of JDBC connection implementation in MySQL using Java

First, create a database in the MySQL Console
SQL code


create database test;

use test;

create table user(username varchar(15),password varchar(20));

insert into user values(‘userone’,’123456’);


You can also use MySQL-front to create

Java code


Package com. dGy. util;

Import java. SQL. connection;

Import java. SQL. drivermanager;

Import java. SQL. resultset;

Import java. SQL. sqlexception;

Import java. SQL. statement;

Public class testjdbc {

/**

* 1. The MySQL driver package used is a mysql-connector-java-5.0.8-bin.jar

* 2. The statement is used to execute a static SQL statement and return the object of the result it generates.

* By default, only one resultset object can be opened for each statement object at a time.

* Therefore, if you read a resultset object and read another object,

* The two objects must be generated by different statement objects.

* If the current resultset object opened by a statement exists,

* All execution methods in the statement interface are implicitly disabled.

* 3. resultset indicates the data table of the database result set, which is usually generated by executing a database query statement.

* The resultset object has a pointer to its current data row. Initially, the pointer is placed before the first line.

* The next method moves the pointer to the next row;

* Because this method returns false if there is no next row in the resultset object,

* You can use it in the while loop to iterate the result set.

**/

Static connection conn = NULL;

Public static connection getconnectionbyjdbc (){

Try {

// Load the driver package

Class. forname (COM. MySQL. JDBC. Driver "); // load the driver

} Catch (classnotfoundexception e ){

System. Out. println ("an exception occurred when loading the driver package! Please check it! ");

E. printstacktrace ();

}

Try {

/** Create a JDBC connection, but pay attention to the first parameter of this method,

* If a communicationsexception exception occurs in 127.0.0.1,

* It may need to be changed to localhost.

**/

// JDBC: mysql: // localhost: 3306/test, and test is a database

Conn = drivermanager. getconnection ("JDBC: mysql: // localhost: 3306/test", "root", "123456 ");

} Catch (sqlexception e ){

System. Out. println ("an exception occurred when connecting to the database! ");

E. printstacktrace ();

}

Return conn;

}

Public static void test (){

String SQL = "select * from user ";

Getconnectionbyjdbc ();

Try {

// Create a JDBC Statement

Statement stmt = conn. createstatement ();

// Execute the query

Resultset rs = stmt.exe cutequery (SQL );

While (Rs. Next ()){

String username = Rs. getstring ("username ");

String Password = Rs. getstring ("password ");

System. Out. println (username + "" + password );

}

} Catch (sqlexception e ){

System. Out. println (E. getmessage ());

E. printstacktrace ();

} Finally {

// Closes the connection proactively (to avoid the connection being closed in the try statement block when an exception occurs)

Try {

If (Conn! = NULL) Conn. Close ();

} Catch (sqlexception e ){

System. Out. println (E. getmessage ());

E. printstacktrace ();

}

}

}

Public static void main (string [] ARGs ){

Testjdbc = new testjdbc ();

Testjdbc. Test ();

}

}