jdbc 增删改

package TommyPackage;

import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.PreparedStatement;
import java.sql.SQLException;

public class MyTest {

    private static Connection getConn() {
        String driver = "com.mysql.jdbc.Driver";
        String url = "jdbc:mysql://127.0.0.1:3306/testdb";
        String username = "root";
        String password = "123456";
        Connection conn = null;
        try {
            Class.forName(driver); //classLoader,加载对应驱动
            conn = DriverManager.getConnection(url, username, password);
        } catch (ClassNotFoundException e) {
            e.printStackTrace();
        } catch (SQLException e) {
            e.printStackTrace();
        }
        return conn;
    }

    public static void main(String[] args) throws ClassNotFoundException, SQLException {
        Connection con = getConn();
        Person ps = new Person();

        ps.setLastName("Tommy");
        ps.setFirstName("Lorry");
        ps.setAddress("电信大楼");
        ps.setCity("Shanghai");

        StringBuilder sb = new StringBuilder();
        sb.append("\'" + ps.getLastName() + "\'");
        sb.append(",");
        sb.append("\'" + ps.getFirstName() + "\'");
        sb.append(",");
        sb.append("\'" + ps.getAddress() + "\'");
        sb.append(",");
        sb.append("\'" + ps.getCity() + "\'");

        if (con != null) {
            System.out.println("mysql 连接成功！");

            //插入
            String s = "" + "insert into Persons(LastName,FirstName,Address,City) values(" + sb.toString() + ")";
            PreparedStatement pst1 = con.prepareStatement(s);
            if (pst1.execute()) {
                System.out.println("插入数据成功！");
            } else {
                System.out.println("插入数据失败！");
            }

            //删除
            String t = "delete from Persons where LastName='" + ps.getLastName() + "'";
            PreparedStatement pst2 = con.prepareStatement(t);
            int i = pst2.executeUpdate();  //i返回删除的记录数
            System.out.println("删除了: " + i + "条数据！");

            //修改
            String Cityname = "London";
            String u = "update Persons set LastName='" + ps.getLastName() + "' where City='" + Cityname + "'";
            PreparedStatement pst3 = con.prepareStatement(u);
            int j = pst3.executeUpdate(); //j返回更新的记录数

            System.out.println("更新了: " + j + "条数据！");

            //关闭资源
            pst1.close();
            pst2.close();
            pst3.close();
            con.close();
        }
    }
}