Question

我有一个疯狂的问题：D我有一个带有Jtable的Java应用程序以及show，add，delete和update按钮。与我的数据库的连接有效。

现在当我将数据插入我的Textfields并点击提交（添加）时，我可以看到Jtable中的条目，但我无法在我的数据库中看到它。

这很疯狂，因为我已经在我的数据库中有一些简单条目的数据，我的JTable显示数据但是当我通过java应用程序插入数据时，我看不到我{{1}中的条目我所连接的......

很难解释，但也许你可以找到问题：/

从JAVA JTABLE查看表格 http://i.imgur.com/BrRUyx9.jpg

PHPMYADMIN.COM的表格视图 http://i.imgur.com/TIbVzmc.jpg

我的代码

CONTROLLER CLASS

phpmyadmin database

MAINFRAME CLASS ...（主要）

public void controllActionListenerAddEquipmentSubmitBtn(){
            main.setActionListenerAddEquipmentSubmitBtn(new ActionListener(){
                @Override
                public void actionPerformed(ActionEvent arg0) {
                    if(arg0.getSource()==main.getButtonAddEquipmentBtn()){
                        EquipmentDAO edao = new EquipmentDAO();
                        try {
                                edao.create(main.addEquipmentSubmit());
                            } catch (SQLException e) {    
                                e.printStackTrace();
                            }
                        }
                    }
                });
            }

DAOCLASS

 public Equipment addEquipmentSubmit(){
        equipment = new Equipment();
        equipment.setName(addEquipment.getName());
        equipment.setSection(addEquipment.getSection());
        equipment.setType(addEquipment.getType());
        equipment.setValue(Double.parseDouble((addEquipment.getValue())));
        equipment.setAmount(Integer.parseInt(addEquipment.getAmount()));
        return equipment;    
    }

ENTITY CLASS

package DAOCollection;

import java.sql.Connection;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;
import java.util.ArrayList;
import java.util.List;

import javax.swing.JOptionPane;

import com.mysql.jdbc.PreparedStatement;

import notesDBMySQL.DatabaseHandler;
import EntityClasses.Equipment;

public class EquipmentDAO implements DaoInterface{

    private Connection con;
    private java.sql.PreparedStatement sta;
    private Statement std;
    private ResultSet res;
    private DatabaseHandler handle;
    private String query;

    @Override
    public ResultSet show() throws SQLException{    
        handle = new DatabaseHandler();
        Connection con = handle.buildConnectionToServer();
        String query = "select EID as ID, EquipmentName as Name, EquipmentSection as Section, EquipmentType as Type, EquipmentValue as Value, EquipmentAmount as Amount from Equipment";
        sta = con.prepareStatement(query);
        res = sta.executeQuery(query);
        return res;    
    }

    @Override
    public void create(Object c) throws SQLException {    
        handle = new DatabaseHandler();
        con = handle.buildConnectionToServer();
        std = con.createStatement();
        Equipment equ = (Equipment) c ;
        query = "INSERT INTO Equipment(EquipmentName,EquipmentSection,EquipmentType,EquipmentValue, EquipmentAmount)"+"VALUES('"+equ.getName()+"','"+equ.getSection()+"','"+equ.getType()+"','"+equ.getValue()+"','"+equ.getAmount()+"')";
        std.execute(query);
        con.commit();
        handle.closeConnection();      
    }

    @Override    
    public void update(Object c) throws SQLException {    
        Equipment equ = (Equipment) c;
        handle = new DatabaseHandler();
        con = handle.buildConnectionToServer();
        query = "UPDATE Equipment SET  name=?,section=?,type=?,value=?,amount=?,"+"WHERE EID=?";
        sta = con.prepareStatement(query);
        sta.setString(1, equ.getName());
        sta.setString(2,equ.getSection());
        sta.setString(3, equ.getType());
        sta.setDouble(4, equ.getValue());
        sta.setInt(5, equ.getAmount());
        sta.setInt(6, equ.getEid());
        sta.executeUpdate();
        sta.close();
        con.close();
        handle.closeConnection();
    }

    @Override
    public void delete(int id) throws SQLException {    
        handle = new DatabaseHandler();
        con = handle.buildConnectionToServer();
        query = "DELETE FROM EQUIPMENT"+"WHERE EID="+id;
        sta.executeUpdate(query);
        sta.close();
        con.close();
        handle.closeConnection();
    }
}

添加课程

package EntityClasses;

public class Equipment {

    private int eid;
    private String name;
    private String section;
    private String type;
    private double value;
    private int amount;

    public int getEid() {
        return eid;
    }

    public void setEid(int eid) {
        this.eid = eid;
    }

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

    public String getSection() {
        return section;
    }

    public void setSection(String section) {
        this.section = section;
    }

    public String getType() {
        return type;
    }

    public void setType(String type) {
        this.type = type;
    }

    public double getValue() {
        return value;
    }

    public void setValue(double value) {
        this.value = value;
    }

    public int getAmount() {
        return amount;
    }

    public void setAmount(int amount) {
        this.amount = amount;
    }


}

Answer 1

您的DAO实施正在寻找麻烦。你永远不应该归还ResultSet。更好的想法是将数据加载到对象或数据结构中，并关闭finally块中方法范围中的ResultSet。所有数据库资源都相同。

无法通过Java应用程序将数据添加到数据库

1 个答案: