普通操作

import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;
import java.util.ArrayList;
import java.util.List;

public class demo {

	public static void main(String[] args) {
      	//jdbd:mysql://地址:端口/数据库名?是否使用Unicode&编码格式&时区
		String url = "jdbc:mysql://localhost:3306/student?useUnicode=true&characterEncoding=utf-8&serverTimezone=Asia/Shanghai";
      	//用户名
		String user = "root";
      	//密码
		String password = "123456";
		Connection con = null;
		Statement stm = null;
		List<Student> list = new ArrayList<Student>();
		try {
          	//建立连接
			con = DriverManager.getConnection(url,user,password);
          	//准备好数据传输对象
			stm = con.createStatement();
          	//发送查询语句
			ResultSet rs = stm.executeQuery("select * from student where name = '游文智'");
			while (rs.next()) {
              	//接受数据
				Student st = new Student(rs.getString("name"), rs.getInt("id"), rs.getString("sno"));
				list.add(st);
			}
		} catch (SQLException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		}finally {
			try {
              	//关闭流
				stm.close();
				con.close();
			} catch (SQLException e) {
				// TODO Auto-generated catch block
				e.printStackTrace();
			}
		}
		list.forEach(i->{
			System.out.println(i);
		});
	}

}

 预加载操作

public List<Double> query(String name) {
		// TODO Auto-generated method stub
  		//SQL语句
		String sql = "SELECT point FROM student a,score b\r\n"
				+ "WHERE a.sno = b.sno AND a.`name` = ?";
		List<Double> list = new ArrayList<Double>();
		PreparedStatement pstm = null;
		try {
          	//预加载SQL语句
			pstm = getCon().prepareStatement(sql);
          	//加载问号的值
			pstm.setString(1, name);
			ResultSet rs = pstm.executeQuery();
			while (rs.next()) {
				Double d = rs.getDouble("point");
				list.add(d);
			}
		} catch (SQLException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		}
		return list;
	}