546 JDBC练习_insert语句和547JDBC练习_update语句

JDBC练习_insert语句

public static void main(String[] args) throws Exception {
        Statement  stmt = null;
        Connection conn= null;
        try {
            //注册驱动
            Class.forName("com.mysql.jdbc.Driver");
            //定义sql语句
            String sql = "insert into account values (null,'Pike',2000)";
            //获取数据库的连接对象
            conn = DriverManager.getConnection("jdbc:mysql://localhost:3306/guo01?useUnicode=true&characterEncoding=utf-8&useSSL=false", "root", "root");
            //获取执行sql的对象Statement
            stmt = conn.createStatement();
            //获取执行sql
            int count = stmt.executeUpdate(sql);
            //处理结果
            System.out.println(count);
            if (count > 0) {
                System.out.println("添加成功");
            } else {
                System.out.println("添加失败");
            }
        }catch (ClassNotFoundException e) {
            e.printStackTrace();
        }finally {
            //避免空指针异常
            //释放资源
            if (stmt !=null){
                stmt.close();
                try {
                    stmt.close();
                }catch (SQLException e){
                    e.printStackTrace();
                }
            }
            if (conn !=null) {
                stmt.close();
                try {
                    conn.close();
                } catch (SQLException e) {
                    e.printStackTrace();
                }

            }
        }
    }
}

JDBC练习_update语句

//修改数据库内容
    //导入jar包
    public static void main(String[] args) {
        Connection conn=null;
        Statement stmt =null;
        try {
            //注册驱动
            Class.forName("com.mysql.jdbc.Driver");
            //获取数据库的连接对象
             conn = DriverManager.getConnection("jdbc:mysql://localhost:3306/guo01?useUnicode=true&characterEncoding=utf-8&useSSL=false", "root", "root");

            //定义sql语句
            String sql = "update account set balance =1500 where id=3";

            //获取执行sql的对象Statement
            stmt = conn.createStatement();

            //获取执行sql
            int count = stmt.executeUpdate(sql);

            //处理结果
            System.out.println(count);
            if (count > 0) {
                System.out.println("修改成功");
            } else {
                System.out.println("修改失败");
            }

        } catch (ClassNotFoundException e) {
            e.printStackTrace();
        } catch (SQLException e) {
            e.printStackTrace();
        }finally {
            //释放资源
            if (stmt !=null){
                try {
                    stmt.close();
                } catch (SQLException e) {
                    e.printStackTrace();
                }
            }
            if (conn !=null){
                try {
                    conn.close();
                } catch (SQLException e) {
                    e.printStackTrace();
                }
            }
        }
    }
}