JDBC实现Mysql的增删查改

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#Mysql #JDBC

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博客介绍了创建工具类DBUtil，利用其对MySQL数据库进行多种操作，包括查询、插入、删除和修改数据，借助JDBC实现数据库交互。

创建工具类DBUtil

public class DBUtil {
    public static Connection getConnection(){
        //1.加载驱动
        try {
            Class.forName("com.mysql.jdbc.Driver");
            //2.创建连接
            Connection connection = DriverManager.getConnection
                    ("jdbc:mysql://127.0.0.1:3306/user?useSSL=true&" +
                            "characterEncoding=utf-8&user=" +
                            "root&password=123");
            return connection;
        } catch (Exception e) {
            e.printStackTrace();
        }
        return null;
    }
}

对数据库进行查询操作

public class Test {
    public static void main(String[] args) {
        ResultSet rs = null;
        Connection connection = null;
        PreparedStatement statement = null;
        try {
            //1.2步
            connection= DBUtil.getConnection();
            System.out.println("创建连接成功");
            //3.写sql查询语句
            String sql = "select*from userinfo";
            //4.得到statement对象
            statement = connection.prepareStatement(sql);
            //5.执行sql得到结果集
            rs = statement.executeQuery();
            //6.处理结果集
            while (rs.next()) {
                System.out.println(rs.getInt(1));
                System.out.println(rs.getString(2));
                System.out.println(rs.getString(3));
            }
            //7.关闭资源
        } catch (Exception e) {
            e.printStackTrace();
        } finally {
            if (rs != null) {
                try {
                    rs.close();
                } catch (SQLException e) {
                    e.printStackTrace();
                }
            }
            if(statement!=null){
                try {
                    statement.close();
                } catch (SQLException e) {
                    e.printStackTrace();
                }
            }
            if(connection!=null){
                try {
                    connection.close();
                } catch (SQLException e) {
                    e.printStackTrace();
                }
            }
        }
    }
}

插入数据操作

public class Insert {
    public static void main(String[] args) {
        Connection connection = null;
        PreparedStatement statement = null;
        try {
            //1.2步
            connection= DBUtil.getConnection();
            //3.写sql查询语句
            String sql = "insert into userinfo (username,password) values (?,?)";
            //4.得到statement对象
            statement = connection.prepareStatement(sql);
            statement.setString(1,"dingshili");
            statement.setString(2,"123");
            statement.executeUpdate();
            //5.执行sql得到结果集
           // rs = statement.executeQuery();
            //6.处理结果集
            //while (rs.next()) {
             //   System.out.println(rs.getInt(1));
              //  System.out.println(rs.getString(2));
              //  System.out.println(rs.getString(3));
            //}
            //7.关闭资源
        } catch (Exception e) {
            e.printStackTrace();
        } finally {
            if(statement!=null){
                try {
                    statement.close();
                } catch (SQLException e) {
                    e.printStackTrace();
                }
            }
            if(connection!=null){
                try {
                    connection.close();
                } catch (SQLException e) {
                    e.printStackTrace();
                }
            }
        }
    }
}

删除数据操作：

public class Delete {
    public static void main(String[] args){
        Connection connection = null;
        PreparedStatement statement = null;
        try {
            //1.2步
            connection= DBUtil.getConnection();
            //3.写sql删除语句
            String sql = "delete from userinfo where id='1'";
            //4.得到statement对象
            statement = connection.prepareStatement(sql);
            //更新数据
            statement.executeUpdate();
        } catch (Exception e) {
            e.printStackTrace();
        } finally {
            if(statement!=null){
                try {
                    statement.close();
                } catch (SQLException e) {
                    e.printStackTrace();
                }
            }
            if(connection!=null){
                try {
                    connection.close();
                } catch (SQLException e) {
                    e.printStackTrace();
                }
            }
        }
    }
}

修改数据操作：

public class Update {
    public static void main(String[] args){
        Connection connection = null;
        PreparedStatement statement = null;
        try {
            //1.2步
            connection= DBUtil.getConnection();
            //3.写sql删除语句
            String sql="update userinfo set id='9' where id='2'";
            //4.得到statement对象
            statement = connection.prepareStatement(sql);
            //更新数据
            statement.executeUpdate();
        } catch (Exception e) {
            e.printStackTrace();
        } finally {
            if(statement!=null){
                try {
                    statement.close();
                } catch (SQLException e) {
                    e.printStackTrace();
                }
            }
            if(connection!=null){
                try {
                    connection.close();
                } catch (SQLException e) {
                    e.printStackTrace();
                }
            }
        }
    }
}