package com.demo; import java.sql.*; public class Demo { public static void main(String[] args) throws ClassNotFoundException, SQLException { //1、加载驱动 Class.forName("com.mysql.jdbc.Driver"); //2、创建连接(DriverManager驱动管理器,创建连接) Connection conn = DriverManager.getConnection("jdbc:mysql:///bjo1", "root", "root"); //3、sql语句执行 statement用来执行sql的对象 Statement statement = conn.createStatement(); //执行更新(增加、删除、修改)返回int 数据代表返回更新的行数(大于0代表有数据被更新) int i = statement.executeUpdate("delete from admin where id = 1"); //执行查询,返回ResultSet结果集 ResultSet rs = statement.executeQuery("select from admin where id = 1"); //4、返回结果 //循环结果集rs.next()循环遍历 while(rs.next()){ //取值方式 //getInt(1) 获取数据库中int类型数据,第一列的值 rs.getInt(1); //getInt("id") 获取数据库中int类型数据,列名叫”id“的这一列的值 rs.getInt("id"); } //5、关闭资源 rs.close(); statement.close(); conn.close(); }} 使用JDBC实现添加功能。 package com.demo; import java.sql.Connection; import java.sql.DriverManager; import java.sql.SQLException; import java.sql.Statement; import java.util.Scanner; public class InsertDemo { public static void main(String[] args) { Connection conn = null; Statement statement = null; Scanner sc = new Scanner(System.in); System.out.println("请输入用户名:"); String name = sc.next(); System.out.println("请输入密码:"); String pw1 = sc.next(); //1、加载驱动 try { Class.forName("com.mysql.jdbc.Driver"); //2、创建连接 /* ur1:数据库连接路径 user:用户名 password:密码 jdbc:mysql://服务器地址:端口号/数据库名字 jdbc:mysql://localhost:3306/news_week1 jdbc:mysql:///news_week1 ClassNotFoundException异常:类没找到 SQLException异常:SQL异常 */ conn = DriverManager.getConnection("jdbc:mysql://localhost:3306/news_week1?characterEncoding=utf-8", "root", "root"); //3、获取执行SQL语句的对象 statement = conn.createStatement(); //4、添加 String sql = "insert into admin values(null,'"+name+"','"+pw1+"')"; //执行sql语句 int i = statement.executeUpdate(sql); //执行更新操作,返回int类型参数(返回执行更新的行数) if (i > 0){ //添加成功 System.out.println("添加成功!"); }else { System.out.println("添加失败"); } } catch (Exception e) { throw new RuntimeException(e); }finally { try { if (statement != null) { statement.close(); } if (conn != null) { conn.close(); } } catch (SQLException e) { throw new RuntimeException(e); } } } }
使用JDBC实现修改功能
package com.demo; import java.sql.Connection; import java.sql.DriverManager; import java.sql.Statement; import java.util.Scanner; public class UpdateDemo { public static void main(String[] args) { Scanner sc = new Scanner(System.in); System.out.println("请输入需要修改的用户名:"); String name = sc.next(); System.out.println("请输入需要修改的密码:"); String pwd = sc.next(); //1、加载驱动 try { Class.forName("com.mysql.jdbc.Driver"); //2、创建连接 Connection conn = DriverManager.getConnection("jdbc:mysql:///news_week1?characterEncoding=utf-8", "root", "root"); //3、获取执行SQL语句的对象 Statement statement = conn.createStatement(); //4、更新密码 int i = statement.executeUpdate("update admin set admin_pwd = '"+pwd+"' where admin_name = '"+name+"'"); //5、判断是否成功 if (i > 0 ){ System.out.println("修改成功!"); }else{ System.out.println("修改失败!"); } statement.close(); conn.close(); } catch (Exception e) { throw new RuntimeException(e); } } }
使用JDBC实现删除功能
package com.demo; import com.mysql.jdbc.Driver; import java.sql.Connection; import java.sql.DriverManager; import java.sql.SQLException; import java.sql.Statement; import java.util.Scanner; public class DeleteDemo { public static void main(String[] args) { Scanner sc = new Scanner(System.in); System.out.println("请输入需要删除的编号:"); String id = sc.next(); Connection conn = null; Statement statement = null; try { Class.forName("com.mysql.jdbc.Driver"); conn = DriverManager.getConnection("jdbc:mysql:///news_week1", "root", "root"); statement = conn.createStatement(); int i = statement.executeUpdate("delete from admin where admin_id = "+id); if (i > 0) { System.out.println("删除成功!"); } else { System.out.println("删除失败!"); } } catch (Exception e) { throw new RuntimeException(e); } finally { try { statement.close(); conn.close(); }catch (Exception e){ } } } }
如何封装数据库操作的工具类 BaseDao
package com.demo; import java.sql.*; public class BaseDao { //定义连接JDBC需要的常量 public static final String driver = "com.mysql.jdbc.Driver"; protected static final String url = "jdbc:mysql://localhost:3306/news_week1?characterEncoding=utf-8"; public static final String user = "root"; public static final String pwd = "root"; static Connection conn = null; static Statement statement = null; static ResultSet rs = null; //1、加载驱动 static { try { Class.forName(driver); } catch (ClassNotFoundException e) { throw new RuntimeException(e); } }//2、创建连接 public static Connection getConn() { try { conn = DriverManager.getConnection(url, user, pwd); } catch (SQLException e) { throw new RuntimeException(e); } return conn; } public static void close() { try { if (rs != null) { rs.close(); }if (statement != null) { statement.close(); }if (conn != null) { conn.close(); } }catch (SQLException e) { throw new RuntimeException(e); } } }
调用BaseDao的方法实现添加和查询功能
package com.demo; import java.sql.Connection; import java.sql.ResultSet; import java.sql.SQLException; import java.sql.Statement; import java.util.ArrayList; public class Test { @org.junit.Test public void select() { //通过工具类加载驱动创建连接(类加载时执行静态代码块) Connection conn = BaseDao.getConn(); //创建可执行sql语句的对象 try { Statement statement = conn.createStatement(); String sql = "select * from admin"; ResultSet rs = statement.executeQuery(sql); ArrayList<Admin> list = new ArrayList<>(); //循环遍历结果集并展示while遍历结果 re.next() while (rs.next()) { Admin admin = new Admin(rs.getInt(1), rs.getString(2), rs.getString(3)); list.add(admin); } for (Admin admin : list) { System.out.println(admin); } } catch (SQLException e) { throw new RuntimeException(e); } } @org.junit.Test public void insert() throws SQLException { Connection conn = BaseDao.getConn(); Statement statement = conn.createStatement(); String sql = "insert into admin values(null,'小米','2313')"; int i = statement.executeUpdate(sql); if (i > 0 ){ System.out.println("添加成功!"); }else{ System.out.println("添加失败!"); } BaseDao.close(); } }标签:JDBC,java,import,数据库,System,statement,sql,操作,conn From: https://blog.csdn.net/Anyway_01/article/details/136973316