java基础——jdbc基本操作

柔光的暖阳◎ 2023-07-01 12:00 69阅读 0赞

package jsbc;
    
    import java.sql.*;
    
    public class TestJDBC { 
        public static void main(String[] args) { 
    
            Connection c = null;
            Statement s = null;
            try { 
                //初始化驱动
                Class.forName("com.mysql.cj.jdbc.Driver");
                System.out.println("数据可加载成功！！！");
    
                //建立数据库连接
                c  = DriverManager.getConnection("jdbc:mysql://127.0.0.1:3306" +
                        "/how2java?characterEncoding=UTF-8&useSSL=false&serverTimezone=UTC","root","123");
                System.out.println("连接成功，获取对象："+c);
    
                //创建Statement语句
                s  = c.createStatement();
    
                //增加
                //String sql = "insert into hero values (null,"+"'提莫'"+","+313.0f+","+50+")";
                /*for(int i=0;i<5;i++){ String sqlStr = "insert into hero values(null,"+"'hero"+i+"'"+","+313.0f+","+50+")"; s.execute(sqlStr); }*/
                //删除
                //String sql = "delete from hero where id=5";
                //修改
                //String sql = "update hero set name = 'new name' where id = 3";
                //s.execute(sql);
                //查询
                String sql = "select * from hero";
                ResultSet rs = s.executeQuery(sql);
                while(rs.next()){ 
                    int id = rs.getInt("id");
                    String name = rs.getString(2);
                    float hp = rs.getFloat("hp");
                    int damage = rs.getInt(4);
                    System.out.printf("%d\t%s\t%f\t%d%n",id,name,hp,damage);
                }
            } catch (ClassNotFoundException e) { 
                e.printStackTrace();
            }catch(SQLException e){ 
                e.printStackTrace();
            }finally{ 
                if(s!=null){ 
                    try { 
                        s.close();
                    } catch (SQLException e) { 
                        e.printStackTrace();
                    }
                }
                if(c!=null){ 
                    try { 
                        c.close();
                    } catch (SQLException e) { 
                        e.printStackTrace();
                    }
                }
            }
        }
    }