1 import java.sql.Connection; 2 import java.sql.DriverManager; 3 import java.sql.PreparedStatement; 4 import java.sql.SQLException; 5 6 public class LinkDatabseInsert{ 7 public static void main(String[] args) throws ClassNotFoundException, SQLException { 8 //1.注册数据库的驱动 9 Class.forName("com.mysql.jdbc.Driver"); 10 //2.获取数据库链接(里面内容依次是:"jdbc:mysql://主机名:端口号/数据库名","用户名","登陆密码") 11 Connection connection = DriverManager.getConnection("jdbc:mysql://rm-uf6lgkv4fd9776rxego.mysql.rds.aliyuncs.com:3306/study","root","whmilyY123!"); 12 //3.须要执行的sql语句(?是占位符,表明一个参数) 13 String sql = "insert into stu(id,name,age) values(?,?,?)"; 14 //4.获取预处理对象,并依次给参数赋值 15 PreparedStatement statement = connection.prepareCall(sql); 16 statement.setInt(1,10); //数据库字段类型是int,就是setInt;1表明第一个参数 17 statement.setString(2,"小明"); //数据库字段类型是String,就是setString;2表明第二个参数 18 statement.setInt(3,16); //数据库字段类型是int,就是setInt;3表明第三个参数 19 //5.执行sql语句(执行了几条记录,就返回几) 20 int i = statement.executeUpdate(); 21 System.out.println(i); 22 //6.关闭jdbc链接 23 statement.close(); 24 connection.close(); 25 } 26 }
1 import java.sql.Connection; 2 import java.sql.DriverManager; 3 import java.sql.PreparedStatement; 4 import java.sql.SQLException; 5 6 public class LinkDatabaseUpdate { 7 public static void main(String[] args) throws ClassNotFoundException, SQLException { 8 //1.注册数据库的驱动 9 Class.forName("com.mysql.jdbc.Driver"); 10 //2.获取数据库链接(里面内容依次是:"jdbc:mysql://主机名:端口号/数据库名","用户名","登陆密码") 11 Connection connection = DriverManager.getConnection("jdbc:mysql://rm-uf6lgkv4fd9776rxego.mysql.rds.aliyuncs.com:3306/study","root","whmilyY123!"); 12 //3.须要执行的sql语句(?是占位符,表明一个参数) 13 String sql = "update stu set name=?,age=? where id=?"; 14 //4.获取预处理对象,并依次给参数赋值 15 PreparedStatement statement = connection.prepareCall(sql); 16 statement.setString(1,"小黄"); //数据库字段类型是String,就是setString;1表明第一个参数 17 statement.setInt(2,28); //数据库字段类型是int,就是setInt;2表明第二个参数 18 statement.setInt(3,10); //数据库字段类型是int,就是setInt;3表明第三个参数 19 //5.执行sql语句(执行了几条记录,就返回几) 20 int i = statement.executeUpdate(); 21 System.out.println(i); 22 //6.关闭jdbc链接 23 statement.close(); 24 connection.close(); 25 } 26 }
1 import java.sql.Connection; 2 import java.sql.DriverManager; 3 import java.sql.PreparedStatement; 4 import java.sql.SQLException; 5 6 public class LinkDatabaseDelete { 7 public static void main(String[] args) throws ClassNotFoundException, SQLException { 8 //1.注册数据库的驱动 9 Class.forName("com.mysql.jdbc.Driver"); 10 //2.获取数据库链接(里面内容依次是:"jdbc:mysql://主机名:端口号/数据库名","用户名","登陆密码") 11 Connection connection = DriverManager.getConnection("jdbc:mysql://rm-uf6lgkv4fd9776rxego.mysql.rds.aliyuncs.com:3306/study","root","whmilyY123!"); 12 //3.须要执行的sql语句(?是占位符,表明一个参数) 13 String sql = "delete from stu where id=?"; 14 //4.获取预处理对象,并依次给参数赋值 15 PreparedStatement statement = connection.prepareCall(sql); 16 statement.setInt(1,9); //字段类型是int,就是setInt;1表明第一个参数 17 //5.执行sql语句(执行了几条记录,就返回几) 18 int i = statement.executeUpdate(); 19 System.out.println(i); 20 //6.关闭jdbc链接 21 statement.close(); 22 connection.close(); 23 } 24 }
1 import java.sql.*; 2 3 public class LinkDatabseSelect { 4 public static void main(String[] args) throws ClassNotFoundException, SQLException { 5 //1.注册数据库的驱动 6 Class.forName("com.mysql.jdbc.Driver"); 7 //2.获取数据库链接(里面内容依次是:"jdbc:mysql://主机名:端口号/数据库名","用户名","登陆密码") 8 Connection connection = DriverManager.getConnection("jdbc:mysql://rm-uf6lgkv4fd9776rxego.mysql.rds.aliyuncs.com:3306/study","root","whmilyY123!"); 9 //3.须要执行的sql语句(?是占位符,表明一个参数) 10 String sql = "select * from stu where id in(?,?)"; 11 //4.获取预处理对象,并给参数赋值 12 PreparedStatement statement = connection.prepareStatement(sql); 13 statement.setInt(1,1); //字段类型是int,就是setInt;1表明第一个参数 14 statement.setInt(2,4); //字段类型是int,就是setInt;2表明第一个参数 15 //5.执行sql语句(返回结果集) 16 ResultSet resultSet = statement.executeQuery(); 17 while(resultSet.next()){ //若是有下一条记录 18 String id = resultSet.getString("id"); //根据列名返回值 19 String name = resultSet.getString("name"); //根据列名返回值 20 int age = resultSet.getInt(3); //根据列的顺序返回值 21 String gender = resultSet.getString(4); //根据列的顺序返回值 22 System.out.println(id+"\t"+name+"\t"+age+"\t"+gender); 23 } 24 //6.关闭jdbc链接 25 resultSet.close(); 26 statement.close(); 27 connection.close(); 28 } 29 }