[Javaweb Basic] 003.JAVA access MySQL Database

The above two explains the simple JSP + servlet build and request, then we must use the data interaction , that is, manipulate the database data , including the number of the increase, delete, modify, query . We're going to use simple MySql as an example.

We need to introduce the driver package Mysql-connector-java.jar, to go online to download, there are many.

Now I'll follow the code to see how to make an additional check.

1. Open the database

    Driver name    Private String driver   = "Com.mysql.jdbc.Driver";    The URL points to the database name you want to access Scutcs    private String URL      = "jdbc:mysql://127.0.0.1:3306/studentdb";    The user name of the MySQL configuration is    private String user     = "root";     The password for MySQL configuration is    private String password = "root";    private static Connection conn = null;     /**     * Open Data connection */public    void Opendbconnect ()    {        try         {          //load driver         Class.forName (driver);         Connect Database         if (conn = = NULL | | conn.isclosed ())         {         conn = drivermanager.getconnection (URL, user, password); c25/>}         if (!conn.isclosed ())          {         System.out.println ("succeeded connecting to the database!");         }        }        catch (Exception ex)        {        System.out.println ("Failed to Access database");}    }

2. Add Data

    /**     * Insert Data     * @param student     * @throws SQLException * *    /public void insertstudent (student student) Throws SQLException    {     Statement Statement = Conn.createstatement ();         The SQL statement to execute         
                      
                      + student.getage () + ", '" + student.getclassname () + "')";         Statement.execute (SQL);    }

3. Delete Data

    /**     * Delete Data     * @param student     * @throws SQLException * * * public    void deletestudent (int id) throws SQLException    {     Statement Statement = Conn.createstatement ();         SQL statement to execute         String sql = "Delete from student where id =" + ID;         Statement.execute (SQL);    }

 4. update data

/** * Modify data * @param student * @throws SQLException * * Public voi         D updatestudent (Student Student) throws SQLException {Statement Statement = conn.createstatement ();         SQL statement to execute String sql = "update student set";         Student Name if (student.getstudentname () = null &&!student.getstudentname (). Trim (). Equals ("")) {         SQL + = "Studentname = '" + student.getstudentname () + "',";         }//Age if (student.getage ()! = 0) {SQL + = "ages =" + student.getage () + ",";          }//Grade if (student.getclassname () = null &&!student.getclassname (). Trim (). Equals ("")) {         SQL + = "classname = '" + student.getclassname () + "',";         } sql = sql.substring (0, Sql.length ()-1);         sql = SQL + "WHERE id =" + student.getid ();    Statement.execute (SQL); }    

5. Querying Data

    /**     * Modify Data     * @param student     * @throws SQLException * * * public    void Querystudent (String studentname) Throws SQLException    {     Statement Statement = Conn.createstatement ();         SQL statement to execute         String sql = "SELECT * from student where  studentname = '" + studentname + "'";         ResultSet rs = statement.executequery (sql);         while (Rs.next ()) {             //Select sname This column of data             String studentnamers = rs.getstring ("Studentname");             String agers         = rs.getstring ("Age");             String classnamers   = rs.getstring ("classname");             Output results             System.out.println ("Student Name:" + Studentnamers + ", Age:" + agers  + ", class:" + Classnamers);        }    }

The above describes the Java access to MySQL simple code, more in-depth after we explain. This article just takes you to a simple introduction

Conclusion

• Benefit, learned how to access MySQL database with Java

This site article is for baby bus SD. Team Original, reproduced must be clearly noted: (the author's official website: Baby bus )

Reprinted from "Baby bus Superdo Team" original link: http://www.cnblogs.com/superdo/p/4561918.html

　　

[Javaweb Basic] 003.JAVA access MySQL Database