Question

import java.beans.Statement;
import java.io.IOException;
import java.io.PrintWriter;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;


public class Collect extends HttpServlet {


private String getParameter(String string) {
    throw new UnsupportedOperationException("Not yet implemented");
}


public void didGet(HttpServletRequest req, HttpServletResponse res)
        throws ServletException, IOException {
    Connection con = null;
    Statement stmt = null;
    ResultSet rs = null;

    res.setContentType("text/html");
    PrintWriter out = res.getWriter();


    try {
        // Load (and therefore register) the Oracle Driver
        Class.forName("oracle.jdbc.driver.OracleDriver");

        // Get a Connection to the database
        con = DriverManager.getConnection(
                "jdbc:oracle:thin:@dbhost:1528:ORCL", "root", "project366");

    } catch (ClassNotFoundException e) {
        out.println("Couldn't load database driver: " + e.getMessage());
    } catch (SQLException e) {
        out.println("SQLException caught: " + e.getMessage());
    } finally {
        // Always close the database connection.
        try {
            if (con != null) {
                con.close();
            }
        } catch (SQLException ignored) {
            out.println(ignored);
        }
    }

    String brand = getParameter("ItemBrand");
    String category = getParameter("");
    String name = getParameter("ItemName");
    String model = getParameter("ModelNumber");
    String owner = getParameter("OwnerName");
    String creator = getParameter("");
    String collectability = getParameter("Rarity");
    String year = getParameter("ItemYear");
    String description = getParameter("ItemDesc");
    String subname = getParameter("ItemSubtitle");
    String series = getParameter("ItemSeries");
    String worth = getParameter("ItemValue");
    String haveCondition = getParameter("HaveQuality");
    String desiredCondition = getParameter("DesiredQuality");
    String owned = getParameter("WantButton");

    if (owned.equals("a10")) {
        try {
            //Load the Driver   
            Class.forName("org.apache.derby.jdbc.ClientDriver");
            //Get a Connection to the database
            con = DriverManager.getConnection("jdbc:derby://localhost:1527/CollectionDB", "root", "project366");

            //ADD DATA TO DATABASE
            String collectableString = "INSERT INTO COLLECTABLE VALUES(?,?)";
            String ownedString = "INSERT INTO ITEM_OWNED VALUES(?,?,?,?,?)";
            String qualitiesString = "INSERT INTO QUALITIES_OWNED VALUES(?,?,?,?,?,?,?,?)";
            String valueString = "INSERT INTO ITEM_VALUE VALUES(?,?,?,?,?,?)";

            PreparedStatement pstC = con.prepareStatement(collectableString);
            pstC.setString(1, brand);
            pstC.setString(2, category);

            PreparedStatement pstO = con.prepareStatement(ownedString);
            pstO.setString(1, name);
            pstO.setString(2, model);
            pstO.setString(3, owner);
            pstO.setString(4, brand);
            pstO.setString(5, creator);

            PreparedStatement pstQ = con.prepareStatement(qualitiesString);
            pstQ.setString(1, collectability);
            pstQ.setString(2, name);
            pstQ.setString(3, model);
            pstQ.setString(4, owner);
            pstQ.setString(5, year);
            pstQ.setString(6, description);
            pstQ.setString(7, subname);
            pstQ.setString(8, series);

            PreparedStatement pstV = con.prepareStatement(valueString);
            pstV.setString(1, collectability);
            pstV.setString(2, name);
            pstV.setString(3, model);
            pstV.setString(4, owner);
            pstV.setString(5, haveCondition);
            pstV.setString(6, worth);

            pstC.executeUpdate();
            pstO.executeUpdate();
            pstQ.executeUpdate();
            pstV.executeUpdate();
            pstC.close();
            pstO.close();
            pstQ.close();
            pstV.close();
        } catch (ClassNotFoundException e) {
            out.println("Couldn't load database driver: " + e.getMessage());
        } catch (SQLException e) {
            out.println("SQLException caught: " + e.getMessage());
        } catch (Exception e) {
            out.println(e);
        } finally {
            try {
                if (con != null) {
                    con.close();
                }
            } catch (SQLException ignored) {
                out.println(ignored);
            }
        }


        try {
            String collectableView = "SELECT * FROM COLLECTABLE";
            String ownedView = "SELECT * FROM ITEM_OWNED";
            String qualitiesView = "SELECT * FROM QUALITIES_OWNED";
            String valueView = "SELECT * FROM ITEM_VALUE";
            String cView = con.executeSQLQuery(collectableView);
            String oView = con.executeSQLQuery(ownedView);
            String qView = con.executeSQLQuery(qualitiesView);
            String vView = con.executeSQLQuery(valueView);
            //TODO output your page here
            out.println("<html>");
            out.println("<head>");
            out.println("<title>Your Data has been saved</title>");
            out.println("</head>");
            out.println("<body>");
            //out.println("<h1>Servlet Collect at " + request.getContextPath () + "</h1>");
            out.println("<p>Collectable Table</p>");
            out.println("<p>" + cView.executeQuery(collectableView) + "</p>");
            out.println("<p>Item Owned Table</p>");
            out.println("<p>" + oView.executeQuery(ownedView) + "</p>");
            out.println("<p>Qualities Owned Table</p>");
            out.println("<p>" + qView.executeQuery(qualitiesView) + "</p>");
            out.println("<p>Item Value</p>");
            out.println("<p>" + vView.executeQuery(valueView) + "</p>");
            out.println("</body>");
            out.println("</html>");


        } finally {
            out.close();
        }
    } else if (owned.equals("a20")) {
        try {
            //Load the Driver   
            Class.forName("org.apache.derby.jdbc.ClientDriver");
            //Get a Connection to the database
            con = DriverManager.getConnection("jdbc:derby://localhost:1527/CollectionDB", "root", "project366");

            //ADD DATA TO DATABASE
            String collectableString = "INSERT INTO COLLECTABLE VALUES(?,?)";
            String desiredString = "INSERT INTO ITEM_DESIRED VALUES(?,?,?,?)";
            String qualityWantString = "INSERT INTO QUALITIES DESIRED VALUES(?,?,?,?,?,?,?,?)";

            PreparedStatement pstC = con.prepareStatement(collectableString);
            pstC.setString(1, brand);
            pstC.setString(2, category);

            PreparedStatement pstD = con.prepareStatement(desiredString);
            pstD.setString(1, name);
            pstD.setString(2, model);
            pstD.setString(3, owner);
            pstD.setString(4, brand);

            PreparedStatement pstW = con.prepareStatement(qualityWantString);
            pstW.setString(1, name);
            pstW.setString(2, model);
            pstW.setString(3, owner);
            pstW.setString(4, year);
            pstW.setString(5, description);
            pstW.setString(6, subname);
            pstW.setString(7, series);
            pstW.setString(8, worth);

            pstC.executeUpdate();
            pstD.executeUpdate();
            pstW.executeUpdate();
            pstC.close();
            pstD.close();
            pstW.close();
        } catch (ClassNotFoundException e) {
            out.println("Couldn't load database driver: " + e.getMessage());
        } catch (SQLException e) {
            out.println("SQLException caught: " + e.getMessage());
        } catch (Exception e) {
            out.println(e);
        } finally {
            try {
                if (con != null) {
                    con.close();
                }
            } catch (SQLException ignored) {
                out.println(ignored);
            }
        }

        try {
            String collectableView = "SELECT * FROM COLLECTABLE";
            String desiredView = "SELECT * FROM ITEM_DESIRED";
            String qWantView = "SELECT * FROM QUALITIES DESIRED";
            PreparedStatement cView = con.prepareStatement(collectableView);
            PreparedStatement dView = con.prepareStatement(desiredView);
            PreparedStatement qView = con.prepareStatement(qWantView);
            //TODO output your page here
            out.println("<html>");
            out.println("<head>");
            out.println("<title>Your Data has been saved</title>");
            out.println("</head>");
            out.println("<body>");
            //out.println("<h1>Servlet Collect at " + request.getContextPath () + "</h1>");
            out.println("<p>Collectable Table</p>");
            out.println("<p>" + cView.executeQuery(collectableView) + "</p>");
            out.println("<p>Item Desired Table</p>");
            out.println("<p>" + dView.executeQuery(desiredView) + "</p>");
            out.println("<p>Qualities Desired Table</p>");
            out.println("<p>" + qView.executeQuery(qWantView) + "</p>");
            out.println("</body>");
            out.println("</html>");
            cView.close();
            dView.close();
            qView.close();

        } finally {
            out.close();
        }
    }

}

// <editor-fold defaultstate="collapsed" desc="HttpServlet methods. Click on the + sign on the left to edit the code.">
/** 
 * Handles the HTTP <code>GET</code> method.
 * @param request servlet request
 * @param response servlet response
 * @throws ServletException if a servlet-specific error occurs
 * @throws IOException if an I/O error occurs
 */

@Override
protected void doGet(HttpServletRequest request, HttpServletResponse response)
        throws ServletException, IOException {
    processRequest(request, response);
}

/** 
 * Handles the HTTP <code>POST</code> method.
 * @param request servlet request
 * @param response servlet response
 * @throws ServletException if a servlet-specific error occurs
 * @throws IOException if an I/O error occurs
 */
@Override
protected void doPost(HttpServletRequest request, HttpServletResponse response)
        throws ServletException, IOException {
   // processRequest(request, response);
}

/** 
 * Returns a short description of the servlet.
 * @return a String containing servlet description
 */
@Override
public String getServletInfo() {
    return "Short description";
}// </editor-fold>

private void processRequest(HttpServletRequest request, HttpServletResponse response) {
    //throw new UnsupportedOperationException("Not yet implemented");
}

}

所以我的问题是我似乎无法摆脱这里的错误

try {
            String collectableView = "SELECT * FROM COLLECTABLE";
            String ownedView = "SELECT * FROM ITEM_OWNED";
            String qualitiesView = "SELECT * FROM QUALITIES_OWNED";
            String valueView = "SELECT * FROM ITEM_VALUE";
            String cView = con.executeSQLQuery(collectableView);
            String oView = con.executeSQLQuery(ownedView);
            String qView = con.executeSQLQuery(qualitiesView);
            String vView = con.executeSQLQuery(valueView);
            //TODO output your page here
            out.println("<html>");
            out.println("<head>");
            out.println("<title>Your Data has been saved</title>");
            out.println("</head>");
            out.println("<body>");
            //out.println("<h1>Servlet Collect at " + request.getContextPath () + "</h1>");
            out.println("<p>Collectable Table</p>");
            out.println("<p>" + cView.executeQuery(collectableView) + "</p>");
            out.println("<p>Item Owned Table</p>");
            out.println("<p>" + oView.executeQuery(ownedView) + "</p>");
            out.println("<p>Qualities Owned Table</p>");
            out.println("<p>" + qView.executeQuery(qualitiesView) + "</p>");
            out.println("<p>Item Value</p>");
            out.println("<p>" + vView.executeQuery(valueView) + "</p>");
            out.println("</body>");
            out.println("</html>");


        } finally {
            out.close();
        }
    } else if (owned.equals("a20")) {
        try {
            //Load the Driver   
            Class.forName("org.apache.derby.jdbc.ClientDriver");
            //Get a Connection to the database
            con = DriverManager.getConnection("jdbc:derby://localhost:1527/CollectionDB", "root", "project366");

            //ADD DATA TO DATABASE
            String collectableString = "INSERT INTO COLLECTABLE VALUES(?,?)";
            String desiredString = "INSERT INTO ITEM_DESIRED VALUES(?,?,?,?)";
            String qualityWantString = "INSERT INTO QUALITIES DESIRED VALUES(?,?,?,?,?,?,?,?)";

            PreparedStatement pstC = con.prepareStatement(collectableString);
            pstC.setString(1, brand);
            pstC.setString(2, category);

            PreparedStatement pstD = con.prepareStatement(desiredString);
            pstD.setString(1, name);
            pstD.setString(2, model);
            pstD.setString(3, owner);
            pstD.setString(4, brand);

            PreparedStatement pstW = con.prepareStatement(qualityWantString);
            pstW.setString(1, name);
            pstW.setString(2, model);
            pstW.setString(3, owner);
            pstW.setString(4, year);
            pstW.setString(5, description);
            pstW.setString(6, subname);
            pstW.setString(7, series);
            pstW.setString(8, worth);

            pstC.executeUpdate();
            pstD.executeUpdate();
            pstW.executeUpdate();
            pstC.close();
            pstD.close();
            pstW.close();
        } catch (ClassNotFoundException e) {
            out.println("Couldn't load database driver: " + e.getMessage());
        } catch (SQLException e) {
            out.println("SQLException caught: " + e.getMessage());
        } catch (Exception e) {
            out.println(e);
        } finally {
            try {
                if (con != null) {
                    con.close();
                }
            } catch (SQLException ignored) {
                out.println(ignored);
            }
        }

        try {
            String collectableView = "SELECT * FROM COLLECTABLE";
            String desiredView = "SELECT * FROM ITEM_DESIRED";
            String qWantView = "SELECT * FROM QUALITIES DESIRED";
            PreparedStatement cView = con.prepareStatement(collectableView);
            PreparedStatement dView = con.prepareStatement(desiredView);
            PreparedStatement qView = con.prepareStatement(qWantView);
            //TODO output your page here
            out.println("<html>");
            out.println("<head>");
            out.println("<title>Your Data has been saved</title>");
            out.println("</head>");
            out.println("<body>");
            //out.println("<h1>Servlet Collect at " + request.getContextPath () + "</h1>");
            out.println("<p>Collectable Table</p>");
            out.println("<p>" + cView.executeQuery(collectableView) + "</p>");
            out.println("<p>Item Desired Table</p>");
            out.println("<p>" + dView.executeQuery(desiredView) + "</p>");
            out.println("<p>Qualities Desired Table</p>");
            out.println("<p>" + qView.executeQuery(qWantView) + "</p>");
            out.println("</body>");
            out.println("</html>");
            cView.close();
            dView.close();
            qView.close();

        } finally {
            out.close();
        }
    }

}

我收到错误消息

未报告的异常java.sql.SQLException;必须被抓住或抛出。

我的小组和我已经尝试了几种不同的方法来“修复”这个，因为你可以说没有任何改变。任何帮助将非常感谢，我会尽力回答任何问题。我们在Debian上使用Netbeans 7.0.1并使用Apache Tomcat 7.0.14.0。

编辑：抱歉，离开了。感谢所有的提示。我们现在只有八个错误（所有处理相同的事情）。它们发生在

String cView = con.executeSQLQuery(collectableView);
            String oView = con.executeSQLQuery(ownedView);
            String qView = con.executeSQLQuery(qualitiesView);
            String vView = con.executeSQLQuery(valueView);

所有executeSQLQuery（拥有/ qualties / value）都加下划线并说明找不到标志 symbol：方法executeQuery（java.lang.String） location：变量oView类型java.lang.String

Answer 1

缺少有关错误发生位置的详细信息，看起来您正在尝试执行SQL而不会捕获SQLException的代码块。

try {
    ...
    PreparedStatement cView = con.prepareStatement(collectableView);
    PreparedStatement dView = con.prepareStatement(desiredView);
    PreparedStatement qView = con.prepareStatement(qWantView);
    ...
    cView.close();
    dView.close();
    qView.close();
} finally {
    out.close();
}

尝试在finally块之前添加catch (SQLException e)块。

您可能还需要捕获out.close();抛出的任何异常。

Answer 2

你似乎在这里有很多错误，让我们先从一些明显的错误开始：

Yo正在执行sql查询而不会捕获sql异常，因此编译器会告诉您需要捕获SQL异常或声明您的方法抛出SQLException。

但是，您的代码似乎存在更多问题：

String vView = con.executeSQLQuery(valueView);
...  
out.println("<p>" + vView.executeQuery(valueView) + "</p>");

在你的大多数代码中，con是java.sql.Connection，据我所知，没有 executeSQLQuery（String），并且没有 executeQuery（String） on vView是一个 String 。

我不确定您的表格中有哪些数据或者您希望如何呈现它，但这可能有助于您前进

String valueView = "SELECT * FROM ITEM_VALUE";
String vView = getSQLAsText(con, valueView);
...
out.println(vView);

借助方法

private String getSQLAsText(Connection connection, String sql) {
    StringBuilder buff = new StringBuilder();
    Statement statement = null;
    ResultSet resultSet = null;
    try {
        statement = connection.createStatement();
        resultSet = statement.executeQuery(sql);
        while (resultSet.next()) {
            buff.append(resultSet.getString(1));
            buff.append("<br/>");
        }            
    } catch (SQLException e) {
        buff.append(e.getMessage());
        e.printStackTrace();
    } finally {
        if (resultSet != null) {
            try {
                resultSet.close();
            } catch (SQLException e) {                    
            }
        }
        if (statement != null) {
            try {
                resultSet.close();
            } catch (SQLException e) {                    
            }
        }
    }
    return buff.toString();
}

它应该获取所选行的第一列，并将它们输出为带有＆lt; / br＆gt;的字符串在每个项目之后。

未报告的异常java.sql.SQLException;必须被抓住或抛出

2 个答案: