Sharing examples of Java connecting to mysql database based on jdbc

This article mainly introduces the operation of Java to connect to mysql database based on jdbc. It analyzes the specific steps and related precautions of using jdbc to connect to mysql database in Java with a complete example. Friends in need can refer to this article

The example describes the operation of Java connecting to mysql database based on jdbc. Share it with everyone for your reference, the details are as follows:

import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;
public class MySQLDemo {
  private Connection conn = null;
  private Statement stmt = null;
  private ResultSet rs = null;
  private String driverclass = "com.mysql.jdbc.Driver";
  private String url = "jdbc:mysql://localhost:3306/mydb";
  private String user = "root";
  private String password = "111111";
  public MySQLDemo() {
    try {
      Class.forName(driverclass).newInstance(); // 加载驱动程序
    } catch (InstantiationException e) {
      // TODO Auto-generated catch block
      e.printStackTrace();
    } catch (IllegalAccessException e) {
      // TODO Auto-generated catch block
      e.printStackTrace();
    } catch (ClassNotFoundException e1) {
      // TODO Auto-generated catch block
      System.out.println("class not found");
    }
    try {
      conn = DriverManager.getConnection(url, user, password); // 获得Connection对象
    } catch (Exception e) {
      System.out.println("Connect failed!");
    }
  }
  public void selectMethod(String sql) {
    System.out.println("id title");
    try {
      stmt = conn.createStatement(); // 获得Statement对象
      rs = stmt.executeQuery(sql); // 执行SQL语句，并返回ResultSet类型的结果
      while (rs.next()) {
        String title = rs.getString("id");
        String name = rs.getString("name");
        System.out.println(title + " " + name);
      }
    } catch (SQLException e) {
      // TODO Auto-generated catch block
      e.printStackTrace();
    }
  }
  public void closeDB() throws SQLException {
    if (rs != null)
      rs.close();
    if (stmt != null)
      stmt.close(); // 关闭Statement对象
    if (conn != null) // 关闭Connection对象
      conn.close();
  }
  public static void main(String args[]) {
    MySQLDemo demo = new MySQLDemo();
    demo.selectMethod("select * from test");
  }
}

The basic steps for using JDBC to connect to the database are similar, except that the URLs between different databases are somewhat different. The basic steps can be divided into the following points:

1. Load the JDBC driver of the corresponding database.
2. Use the driver manager DriverManager to obtain the Connection.
3. Obtain the Statement object through the connection object Connection to facilitate the execution of SQL statements.
4. The result is returned in ResultSet type, and the ResutlSet results are traversed through a while loop until the loop ends when ResultSet.next() is empty.
5. Close Statement and Connection.

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