Java Connection Mysql database and the method of content query _mysql

Recently used the framework to do a few projects, feeling that the bottom of the things a bit forgotten, write a JDBC Simple connection code to familiarize yourself with the review, but also hope that the new contact to help the novice. This is also my first essay, nonsense not much to say, directly on the code:

Public Connection Getcon () {
    //database connection name
    String username= "root";
    Database connection password
    String password= "";
    String driver= "Com.mysql.jdbc.Driver";
    Where test is the database name
    String url= "Jdbc:mysql://localhost:3306/test";
    Connection Conn=null;
    try{
      Class.forName (driver);
      Conn= (Connection) drivermanager.getconnection (Url,username,password);
    } catch (Exception e) {
      e.printstacktrace ();
    }
    return conn;
  }

Through the above code can be directly connected to the database, of course, you must import the database connected to the relevant jar package Mysql-connector-java-5.1.5-bin.jar (can be downloaded by oneself Baidu). Then the following are the methods of the query:

Public list<string> Getselect () { 
//SQL statement
    String sql = "SELECT * from user"; 
Gets to the connection
    Connection conn = Getcon ();
    PreparedStatement PST = NULL;
    Define a list to accept the contents of a database query
    list<string> List = new arraylist<string> ();
    try {
      PST = (preparedstatement) conn.preparestatement (SQL);
      ResultSet rs = Pst.executequery ();
      while (Rs.next ()) {
        //Add the contents of the query to the list, where UserName is the name of the field in the database
        List.add (rs.getstring ("UserName"));
      }
    catch (Exception e) {
    } return
    list;
  }

At this point can be in the database query data, I tested the database name for test, the new table name is user, inside the field only a username, we can add according to their own needs, the following is the test of the above content:

public static void Main (string[] args) {
//where Testdao is the class name
    Testdao DAO = new Testdao ();
A new list gets the collection returned in the Query method
    list<string> List = Dao.getselect ();
The resulting list is traversed for output to the console for
    (int i = 0; i < list.size (); i++) {
      System.out.println (List.get (i));
    }
  }

For convenience, the above three methods are written in Testdao this class, of course, after copying the code needs to import the corresponding package, import package shortcut key for Ctrl+shift+o, if there is any shortage or wrong place hope everyone points out, look forward to common progress

The above is a small series for you to bring the Java connection MySQL database and Content Query method all content, I hope that we support cloud Habitat Community ~