java JDBC系列教程之JDBC类的简析与JDBC的基础操作

package JDBC;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.SQLException;
import java.sql.Statement;
public class Main {
  public static void main(String[] args) throws ClassNotFoundException, SQLException {
    //注册驱动
    Class.forName("com.mysql.jdbc.Driver");
    //获取数据库连接对象
    Connection connection = DriverManager.getConnection("jdbc:mysql://localhost:3309/db2", "root", "1234");
    //定义sql语句
    String sql="update count set money=10000";
    //定义statement执行语句
    Statement statement = connection.createStatement();
    //执行sql语句
    int i = statement.executeUpdate(sql);
    System.out.println("共"+i+"行受到影响");
    //关闭资源
    statement.close();
    connection.close();
  }
}

Class.forName("com.mysql.jdbc.Driver");

package com.mysql.jdbc;
import java.sql.DriverManager;
import java.sql.SQLException;
public class Driver extends NonRegisteringDriver implements java.sql.Driver {
  public Driver() throws SQLException {
  }
  static {
    try {
    //注册驱动
      DriverManager.registerDriver(new Driver());
    } catch (SQLException var1) {
      throw new RuntimeException("Can't register driver!");
    }
  }
}

**1.4ResultSet：结果集对象，封装查询结果**
 boolean next（）：游标向下移动一行，判断当前行是不是最后一行，如果是则返回false，如果不是则返回true
 getXxx(参数)：获取数据
* Xxx：代表数据类型  如： int getInt() ,	String getString()
			* 参数：
				1. int：代表列的编号,从1开始  如： getString(1)
				2. String：代表列名称。 如： getDouble("balance")

package JDBC;
import java.sql.*;
public class Main {
  public static void main(String[] args) throws ClassNotFoundException, SQLException {
    //注册驱动
    Class.forName("com.mysql.jdbc.Driver");
    //获取数据库连接对象
    Connection connection = DriverManager.getConnection("jdbc:mysql://localhost:3309/db2", "root", "1234");
    //定义sql语句
    String sql="SELECT *FROM COUNT ";
    //定义statement执行语句
    Statement statement = connection.createStatement();
    //执行sql语句
    ResultSet resultSet = statement.executeQuery(sql);
    //循环输出
    while(resultSet.next()){
      int anInt = resultSet.getInt(1);
      String string = resultSet.getString(2);
      int anInt2 = resultSet.getInt(3);
      System.out.println("ID:"+anInt);
      System.out.println("name:"+string);
      System.out.println("money:"+anInt2);
    }
    //关闭资源
    statement.close();
    connection.close();
  }
}