连接mysql数据库2+操作入门

package 对数据库操作Statment;



import java.sql.Connection;

import java.sql.DriverManager;

import java.sql.ResultSet;

import java.sql.Statement;

import java.util.Scanner;



import org.junit.After;

import org.junit.Before;

import org.junit.Test;



public class query {

    /**

     * query

     * 

     * @throws Exception

     */

    @Test

    public void query() throws Exception {

        // 声明ststment对象用语执行sql

        Statement st = con.createStatement();

        // sql

        String sql = "select * from stud";

        // 查询返回结果集

        ResultSet rs = st.executeQuery(sql);

        // 遍历

        while (rs.next()) {



            String id = rs.getString("id");

            String name = rs.getString("name");

            System.err.println("编号:" + id + "，" + "姓名" + name);



        }



    }



    /**

     * 删除

     * 

     * @throws Exception

     */

    @Test

    public void del() throws Exception {

        Scanner sc = new Scanner(System.in);

        System.err.println("plz enter id for del:");

        String id = sc.nextLine();



        Statement st = con.createStatement();

        String sql = "delete from stud where id=" + id;

        System.err.println("sql is:" + sql);

        st.executeUpdate(sql);

    }



    /**

     * save

     * 

     * @throws Exception

     */

    @Test

    public void save() throws Exception {

        Scanner sc = new Scanner(System.in);

        System.err.println("输入id");

        String id = sc.nextLine();

        System.err.println("输入name");

        String nm = sc.nextLine();

        Statement st = con.createStatement();

        String sql = "insert into stud values(" + id + ",'" + nm + "')";

        System.err.println("sql is:" + sql);

        st.executeUpdate(sql);



    }



    @Before

    // 执行Test前执行

    public void getCon() throws Exception {

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

        String url = "jdbc:mysql://127.0.0.1:3306/abc?useUnicode=true&characterEncoding=utf8";

        con = DriverManager.getConnection(url, "root", "1234");

        // con.close();

        // System.err.println(con);



    }



    @After

    // 执行Test后执行

    public void closeConn() throws Exception {

        if (con != null || !con.isClosed()) {



            con.close();

        }



    }



    private Connection con;



}