java - 如何使用 Java servlet 将值插入到 mysql 数据库？

Question

(抱歉我有大量代码，但我真的不知道多少才足够)

我在将值插入 mysql 数据库时遇到问题。我使用 Jsp 文件而不是 html 文件。我不断收到此错误，但不确定是什么原因造成的。

public class AddTo extends HttpServlet {

    protected void processRequest(HttpServletRequest request, HttpServletResponse response)throws ServletException, IOException, SQLException {
    response.setContentType("text/html;charset=UTF-8");

    {

        String name = request.getParameter("name");

        String dbURL = "jdbc:mysql://localhost:3306/movieDB";
        String username = "root";
        String password = "sund ";

        try {
            Connection conn = (Connection) DriverManager.getConnection(
            dbURL, username, password);

            } 

        catch (SQLException ex) {
            Logger.getLogger(AddTo.class.getName()).log(Level.SEVERE, null, ex);
            }

        String query = "INSERT INTO table1 " + "VALUES ('" + name + "')";
        Statement statement = null;

        statement = (Statement) conn.createStatement();


        statement.executeUpdate(query);


        Movie aMovie = new Movie(request.getParameter("name"));
        request.setAttribute("user", aMovie);
        String cartRadio = request.getParameter("cartRadio");

        if ( cartRadio.equalsIgnoreCase("cartSelect") ) {

            String url = "/jsp2.jsp";
            RequestDispatcher dispatcher = getServletContext().getRequestDispatcher(url);
            dispatcher.forward(request,response);   
        }

        if ( cartRadio.equalsIgnoreCase("listSelect")) {

            String url = "/jsp3.jsp";
            RequestDispatcher dispatcher = getServletContext().getRequestDispatcher(url);
            dispatcher.forward(request,response);
        }

        if ( cartRadio.equalsIgnoreCase("none")) {

            String url = "/jsp4.jsp";
            RequestDispatcher dispatcher = getServletContext().getRequestDispatcher(url);
            dispatcher.forward(request,response);
        }
    }
}

protected void doGet(HttpServletRequest request, HttpServletResponse response)
        throws ServletException, IOException {
    try {
        processRequest(request, response);
    } catch (SQLException ex) {
        Logger.getLogger(AddTo.class.getName()).log(Level.SEVERE, null, ex);
    }
}

protected void doPost(HttpServletRequest request, HttpServletResponse response)
        throws ServletException, IOException {
    try {
        processRequest(request, response);
    } catch (SQLException ex) {
        Logger.getLogger(AddTo.class.getName()).log(Level.SEVERE, null, ex);
    }
}

private Object getServletContext() {
    throw new UnsupportedOperationException("Not supported yet."); //To change body of generated methods, choose Tools | Templates.
}
}

我不断收到的一个错误是“不兼容的类型要求:com.mysql.jdbc.Statement 发现:java.sql.Statement”，其中“statement = conn.createStatement();”是。

Answer 1

看来您有导入声明

import com.mysql.jdbc.Statement;

而不是

import java.sql.Statement;

这已在本网站上多次说明，但您应该考虑使用 PreparedStatement相反，为了防止 SQL Injection attacks .