JDBC is used in Java to manipulate a simple instance of a database

Since I haven't written a database application in a long time, here's a review of Java JDBC.

1. Operating a database using Java JDBC generally requires six steps:

(1) establish the JDBC bridge and load the database driver;

(2) connect to the database and obtain the Connection object (using the database Connection address, user name and password);

(3) obtain database Statement object;

(4) perform database operations;

(5) read the result;

(6) close the database connection;

2. Using Java JDBC to operate database (mysql) code:

To connect to mysql database, you need to import the mysql database jar package. This code USES mysql-connector-java-5.1.18-bin.jar.

import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.Statement;
import java.sql.ResultSet;

public class MyTest {
  public static void main(String args[]) {
    Connection con = null;
    Statement st = null;
    ResultSet rs = null;
    try {
      //Get an instance of mysql-driven
      Class.forName("com.mysql.jdbc.Driver").newInstance();
      //Get the connection object (provide: address, username, password)
      con = DriverManager.getConnection("jdbc:mysql://127.0.0.1/Weather","root", "root");
    
      if (!con.isClosed())
        System.out.println("Successfully connected ");
      else
        System.out.println("failed connected");
      
      //Create a Statement, a database object
      st = con.createStatement();
      //Run the SQL query statement
      rs = st.executeQuery("select * from Weather.question_type_1;");
      //Read result set
      while (rs.next()) {
        System.out.println("column1:"+rs.getInt(1));
        System.out.println("column2:"+rs.getString(2));
        System.out.println("column3:"+rs.getString(3));
        System.out.println("column4:"+rs.getString(4));
      }
      //Close links
      con.close();
    } catch(Exception e) {
      System.err.println("Exception: " + e.getMessage());
    }
  }
}