c# - 如何从 C# 转换为 Java JDBC

Question

我有以下代码，使用 C# 来操作 SQL Server 中的数据:

using (SqlConnection myDatabaseConnection = new SqlConnection(myConnectionString.ConnectionString))
{
    myDatabaseConnection.Open();
    using (SqlCommand SqlCommand = new SqlCommand("Select * from Users where Username = @UserName and Password = @Password", myDatabaseConnection))
    {
        SqlCommand.CommandType = CommandType.Text;
        SqlCommand.Parameters.AddWithValue("@UserName", TextBox1.Text);
        SqlCommand.Parameters.AddWithValue("@Password", TextBox2.Text);
        SqlDataReader DR1 = SqlCommand.ExecuteReader();
        if (DR1.Read())
        {
            //some code
        }
    }
}

如何使用 JDBC 和 MySQL 作为数据库将其转换为 Java？我可以避免 SQL 注入(inject)吗？

我的尝试:

try (Connection conn = DriverManager.getConnection(dbURL, username, password)) {
    String sql = "Select * from Users where Username = @UserName and Password = @Password";
    Statement statement = conn.createStatement();
    //parameters?
    ResultSet result = statement.executeQuery(sql);
    while (result.next()) {
        //some code
    }        
} catch (SQLException ex) {
    ex.printStackTrace();
}

Answer 1

JDBC 使用 ? 字符作为绑定(bind)变量通常所在的占位符。您必须使用 PreparedStatement 才能使用 ? 占位符。然后你可以调用setXXX方法(这里是从1开始索引!)来绑定(bind)变量然后执行。

String sql = "Select * from Users where Username = ? and Password = ?";
PreparedStatement pStatement = conn.prepareStatement(sql);
pStatement.setString(1, username);
pStatement.setString(2, password);
ResultSet rs = statement.executeQuery();