Defaultlistmodel 从 jtextfield 添加两次项目
Defaultlistmodel adds twice an item from jtextfield
我正在尝试制作一个应用程序，将用户添加的一些字符串发送到我的 SQL 服务器。然而，当我尝试从 jtextfield 向我的 jlist 添加一个字符串时，它被添加了两次..
事情是这样的
用户将名称添加到 jtextfield 。当他点击 + 按钮时，它被发送到 jlist
public void addBrand() {
int index = BrandList.getSelectedIndex(); // get selected index
if (index == -1) { // no selection, so insert at beginning
index = 0;
}
else { // add after the selected item
index++;
}
model.insertElementAt(BrandLbl.getText(), index);
BrandLbl.setText(null);
}
一切正常，我看到一个项目添加到我的 jlist
当用户确定列表已完成时，他点击 "next" 按钮并
调用了 sendArraytoDB(JList list) 方法
public static void sendArraytoDB(JList<String> list){
Connection con = null;
PreparedStatement stm = null;
String updQuery = "insert into brand_names (name) values (?)";
try{
con = DB.getConnection();
//con.setAutoCommit(false);
int x =1;
stm = con.prepareStatement(updQuery);
int f = list.getModel().getSize();
System.out.print(f);
for (int i=0; i<list.getModel().getSize(); i++){
String name =list.getModel().getElementAt(i);
stm.setString(x, name);
//try{
stm.executeUpdate();
//}finally{
//stm.close();
//}
}
}catch(SQLException ex){
System.out.printf("error while sending array to db");
ex.printStackTrace();
}finally{
if (stm != null){
等等……
我的运气不好，我的数据库显示发送了两个名字..
我不能 post 图片所以它喜欢
aa brand
1
2 "the string i sent"
列表在我的记录之前总是多了一条空记录...
试图看到 wtf 正在发生我在发送之前计算了列表大小
int f = list.getModel().getSize();
System.out.print(f);
答案是 2 ...如果我输入 3 记录它的 6 .. 等等...
自从将 addBrand() 方法更改为
后，我将问题缩小到模型
public void addBrand() {
String all = "xghxc";
model.addElement(all);
}
在我自己惊奇的眼前无礼地展示了 "xghxc" 中的两个同时添加到我的列表中
我搜索了 google 但它甚至没有和我的类似的问题:(
我需要的是代码或建议或 smth 来指出 不要在我的记录中添加空的无用记录
这是我的完整代码，供有耐心和时间的人使用
MyMain.java
package tweGraf;
import javax.swing.JFrame;
public class MyMain {
public static void main(String[] args) {
// TODO Auto-generated method stub
Gui g = new Gui();
DB.MakePool();
g.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
g.setSize(1000, 800);
g.setVisible(true);
}
}
Gui.java
package tweGraf;
import javax.swing.*;
import java.awt.*;
import java.awt.event.*;
import java.sql.SQLException;
import java.util.logging.Level;
import java.util.logging.Logger;
public class Gui extends JFrame {
/**
*
*/
private static final long serialVersionUID = 1L;
private JFrame frameYesNo = new JFrame();
String message = "all data will perish. are you sure";
private JPanel Container = new JPanel(); // panels
private JPanel FirstPanel = new JPanel();
private JPanel NewSession = new JPanel();
private JPanel LoadSession = new JPanel();
private JPanel LoadList = new JPanel();
private JPanel GraphSub1 = new JPanel();
private JPanel GraphSub2 = new JPanel();
private JPanel GraphSub3 = new JPanel();
private JTabbedPane GraphPanel = new JTabbedPane();
private JButton NewSessBtn = new JButton(); // buttons
private JButton LoadSessBtn = new JButton();
private JButton BackFP = new JButton();
private JButton plusBrand = new JButton();
private JButton minusBrand = new JButton();
private JButton Next = new JButton();
private JLabel EnterBrandLbl = new JLabel(
"Please insert brands for analysis "); // Labels
private JTextField BrandLbl = new JTextField(20); // textfields
public DefaultListModel<String> model = new DefaultListModel<String>
public JList BrandList = new JList(model); // list
private JScrollPane MyScrollPane = new JScrollPane(BrandList);
private CardLayout cardLayout = new CardLayout(); // layouts
private GridBagLayout MyLayout = new GridBagLayout();
GridBagConstraints MyConstr = new GridBagConstraints();
public Gui() {
super("twegraph");
NewSessBtn.setText("New Session"); // button configuration
LoadSessBtn.setText("Load Session");
BackFP.setText("Back");
plusBrand.setText("+");
minusBrand.setText("-");
Next.setText("Next");
actionListener al = new actionListener();
NewSessBtn.addActionListener(al); // add action listeners
LoadSessBtn.addActionListener(al);
BackFP.addActionListener(al);
plusBrand.addActionListener(al);
minusBrand.addActionListener(al);
Next.addActionListener(al);
plusBrand.addActionListener(al);
minusBrand.addActionListener(al);
Container.setLayout(cardLayout); // panels to container+
Container.add(FirstPanel, "FirstPanel");
Container.add(NewSession, "NewSession");
Container.add(LoadSession, "LoadSession");
Container.add(GraphPanel, "GraphPanel");
Container.add(LoadList, "LoadList");
FirstPanel.setLayout(MyLayout); // first panel
MyConstr.gridwidth = 3;
MyConstr.gridheight = 3;
MyConstr.weightx = 1.0;
MyConstr.weighty = 1.0;
MyConstr.ipadx = 100;
MyConstr.ipady = 50;
MyConstr.insets = new Insets(50, 20, 50, 20);
MyConstr.gridx = 1;
MyConstr.gridy = 0;
MyConstr.anchor = GridBagConstraints.NORTH;
MyLayout.setConstraints(NewSessBtn, MyConstr);
FirstPanel.add(NewSessBtn);
MyConstr.gridx = 1;
MyConstr.gridy = 2;
MyConstr.anchor = GridBagConstraints.SOUTH;
MyLayout.setConstraints(LoadSessBtn, MyConstr);
FirstPanel.add(LoadSessBtn);
NewSession.setLayout(MyLayout); // New Session panel
MyConstr.gridwidth = 3;
MyConstr.gridheight = 3;
MyConstr.ipadx = 0; // size
MyConstr.ipady = 0; // size
MyConstr.gridx = 0;
MyConstr.gridy = 2;
MyConstr.insets = new Insets(10, 20, 10, 20);
MyConstr.anchor = GridBagConstraints.SOUTHWEST;
MyLayout.setConstraints(BackFP, MyConstr);
NewSession.add(BackFP);
MyConstr.anchor = GridBagConstraints.SOUTHEAST;
MyLayout.setConstraints(Next, MyConstr);
NewSession.add(Next);
MyConstr.ipadx = 0; // size
MyConstr.ipady = 0; // size
MyConstr.gridx = 0; // place
MyConstr.gridy = 1; // place
MyConstr.insets = new Insets(0, 0, 0, 0);
MyConstr.anchor = GridBagConstraints.PAGE_START;
MyLayout.setConstraints(EnterBrandLbl, MyConstr);
NewSession.add(EnterBrandLbl);
MyConstr.gridx = 0;
MyConstr.gridy = 1;
MyConstr.anchor = GridBagConstraints.CENTER;
MyLayout.setConstraints(BrandLbl, MyConstr);
NewSession.add(BrandLbl);
MyConstr.gridx = 2;
MyConstr.gridy = 1;
MyConstr.anchor = GridBagConstraints.LAST_LINE_START;
MyLayout.setConstraints(plusBrand, MyConstr);
NewSession.add(plusBrand);
MyConstr.gridx = 2;
MyConstr.gridy = 1;
MyConstr.anchor = GridBagConstraints.LAST_LINE_END;
MyLayout.setConstraints(minusBrand, MyConstr);
NewSession.add(minusBrand);
MyConstr.ipadx = 0; // size
MyConstr.ipady = 0;
MyConstr.gridx = 0;
MyConstr.gridy = 1;
MyConstr.anchor = GridBagConstraints.SOUTH;
MyLayout.setConstraints(MyScrollPane, MyConstr);
NewSession.add(MyScrollPane);
GraphPanel.addTab("overall",GraphSub1); //Graph panel
GraphPanel.addTab("tweets/time",GraphSub2);
GraphPanel.addTab("fame",GraphSub3);
this.setContentPane(Container);
cardLayout.show(Container, "FirstPanel");
}
public class actionListener implements ActionListener {
public void actionPerformed(ActionEvent event) {
JButton src = (JButton) event.getSource();
int answer = 0;
if (src.equals(NewSessBtn))
{
answer = JOptionPane.showConfirmDialog(frameYesNo, message);
if (answer == JOptionPane.YES_OPTION) {
cardLayout.show(Container, "NewSession");
try {
DB.flushData();
} catch (SQLException ex) {
Logger.getLogger(Gui.class.getName()).log(Level.SEVERE, null, ex);
}
} else if (answer == JOptionPane.NO_OPTION) {
frameYesNo.dispose();
}
}
if (src.equals(LoadSessBtn)){
cardLayout.show(Container, "LoadSession");
}
if (src.equals(BackFP)){
cardLayout.show(Container, "FirstPanel");
}
if (src.equals(Next)){
cardLayout.show(Container, "GraphPanel");
DB.sendArraytoDB(BrandList);
}
if (src.equals(plusBrand)){
addBrand();
}
if (src.equals(minusBrand))
{
removeBrand();
}
}
}
public void addBrand() {
/*int index = BrandList.getSelectedIndex(); // get selected index
if (index == -1) { // no selection, so insert at beginning
index = 0;
}
else { // add after the selected item
index++;
}*/
String all = "xghxc";
//model.insertElementAt(BrandLbl.getText(), index);
model.addElement(all);
//BrandLbl.setText(null);
}
public void removeBrand() {
int index2 = BrandList.getSelectedIndex();
if (index2 != -1){
model.remove(index2);
}
int size = model.getSize();
if (size == 0) {
minusBrand.setEnabled(false);
} else {
//if (index == model.getSize()) {
//index--;
//}
}
}
}
DB.java
package tweGraf;
import com.mchange.v2.c3p0.ComboPooledDataSource;
import java.sql.*;
import java.util.logging.Level;
import java.util.logging.Logger;
import javax.swing.JList;
/**
*
* @author cheval
*/
public class DB {
static final String JDBC_DRIVER = "com.mysql.jdbc.Driver";
static final String DB_URL = "jdbc:mysql://localhost:3306/twegrahpdb";
static final String USER = "root";
static final String PASS = "Xrt38H0a";
private static ComboPooledDataSource cdps = new ComboPooledDataSource();
public static void MakePool(){
try {
cdps = new ComboPooledDataSource();
cdps.setDriverClass(JDBC_DRIVER);
cdps.setJdbcUrl(DB_URL);
cdps.setUser(USER);
cdps.setPassword(PASS);
cdps.setMaxPoolSize( 50 );
cdps.setMaxStatements(50);
}catch(Exception ex){
System.out.printf("error smth wrong happened");
}
}
public static Connection getConnection() throws SQLException{
return cdps.getConnection();
}
public static void flushData() throws SQLException{
Statement stm = null;
Connection con = null;
try{
con = DB.getConnection();
stm = con.createStatement();
String flushquery1 = "TRUNCATE json_cache";
String flushquery2 = "TRUNCATE tweets";
String flushquery3 = "TRUNCATE tweet_mentions";
String flushquery4 = "TRUNCATE tweet_tags";
String flushquery5 = "TRUNCATE tweet_urls";
String flushquery6 = "TRUNCATE users";
String flushquery7 = "TRUNCATE brand_names";
stm.executeUpdate(flushquery1);
stm.executeUpdate(flushquery2);
stm.executeUpdate(flushquery3);
stm.executeUpdate(flushquery4);
stm.executeUpdate(flushquery5);
stm.executeUpdate(flushquery6);
stm.executeUpdate(flushquery7);
}catch (SQLException e) {
System.out.printf("error executing db clear");
} finally {
if (stm != null){
try{
stm.close();
System.out.printf("statement closed successfuly \n");
} catch (SQLException e){
System.out.printf("error closing statement");
}
}
if (con != null){
try{
con.close();
System.out.printf("connection closed succesfully \n");
} catch (SQLException e){
System.out.printf("error closing connection");
}
}
}
}
public static void sendArraytoDB(JList<String> list){
Connection con = null;
PreparedStatement stm = null;
String updQuery = "insert into brand_names (name) values (?)";
try{
con = DB.getConnection();
//con.setAutoCommit(false);
int x =1;
stm = con.prepareStatement(updQuery);
int f = list.getModel().getSize();
System.out.print(f);
for (int i=0; i<list.getModel().getSize(); i++){
String name =list.getModel().getElementAt(i);
stm.setString(x, name);
//try{
stm.executeUpdate();
//}finally{
//stm.close();
//}
}
}catch(SQLException ex){
System.out.printf("error while sending array to db");
ex.printStackTrace();
}finally{
if (stm != null){
try {
stm.close();
} catch (SQLException ex) {
Logger.getLogger(DB.class.getName()).log(Level.SEVERE, null, ex);
}
}
if (con != null){
try {
con.close();
} catch (SQLException ex) {
Logger.getLogger(DB.class.getName()).log(Level.SEVERE, null, ex);
}
}
}
}
}
如果你仍然不知道，请不要关心我的实际问题，但 仍然 看到关于我的编码风格或技术的错误 post 它
感谢您的宝贵时间
i narrowed the problem to the model since changing the addBrand() method to...
所以这告诉我 addBrand() 方法被调用了多次。
plusBrand.addActionListener(al);
minusBrand.addActionListener(al);
Next.addActionListener(al);
plusBrand.addActionListener(al);
minusBrand.addActionListener(al);
正如您在上面看到的那样，您向按钮添加了两次侦听器。
我正在尝试制作一个应用程序，将用户添加的一些字符串发送到我的 SQL 服务器。然而，当我尝试从 jtextfield 向我的 jlist 添加一个字符串时，它被添加了两次..
事情是这样的
用户将名称添加到 jtextfield 。当他点击 + 按钮时，它被发送到 jlist
public void addBrand() {
int index = BrandList.getSelectedIndex(); // get selected index
if (index == -1) { // no selection, so insert at beginning
index = 0;
}
else { // add after the selected item
index++;
}
model.insertElementAt(BrandLbl.getText(), index);
BrandLbl.setText(null);
}
一切正常，我看到一个项目添加到我的 jlist
当用户确定列表已完成时，他点击 "next" 按钮并 调用了 sendArraytoDB(JList list) 方法
public static void sendArraytoDB(JList<String> list){
Connection con = null;
PreparedStatement stm = null;
String updQuery = "insert into brand_names (name) values (?)";
try{
con = DB.getConnection();
//con.setAutoCommit(false);
int x =1;
stm = con.prepareStatement(updQuery);
int f = list.getModel().getSize();
System.out.print(f);
for (int i=0; i<list.getModel().getSize(); i++){
String name =list.getModel().getElementAt(i);
stm.setString(x, name);
//try{
stm.executeUpdate();
//}finally{
//stm.close();
//}
}
}catch(SQLException ex){
System.out.printf("error while sending array to db");
ex.printStackTrace();
}finally{
if (stm != null){
等等……
我的运气不好，我的数据库显示发送了两个名字.. 我不能 post 图片所以它喜欢
aa brand
1
2 "the string i sent"
列表在我的记录之前总是多了一条空记录... 试图看到 wtf 正在发生我在发送之前计算了列表大小
int f = list.getModel().getSize();
System.out.print(f);
答案是 2 ...如果我输入 3 记录它的 6 .. 等等...
自从将 addBrand() 方法更改为
后，我将问题缩小到模型public void addBrand() {
String all = "xghxc";
model.addElement(all);
}
在我自己惊奇的眼前无礼地展示了 "xghxc" 中的两个同时添加到我的列表中
我搜索了 google 但它甚至没有和我的类似的问题:(
我需要的是代码或建议或 smth 来指出 不要在我的记录中添加空的无用记录
这是我的完整代码，供有耐心和时间的人使用
MyMain.java
package tweGraf;
import javax.swing.JFrame;
public class MyMain {
public static void main(String[] args) {
// TODO Auto-generated method stub
Gui g = new Gui();
DB.MakePool();
g.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
g.setSize(1000, 800);
g.setVisible(true);
}
}
Gui.java
package tweGraf;
import javax.swing.*;
import java.awt.*;
import java.awt.event.*;
import java.sql.SQLException;
import java.util.logging.Level;
import java.util.logging.Logger;
public class Gui extends JFrame {
/**
*
*/
private static final long serialVersionUID = 1L;
private JFrame frameYesNo = new JFrame();
String message = "all data will perish. are you sure";
private JPanel Container = new JPanel(); // panels
private JPanel FirstPanel = new JPanel();
private JPanel NewSession = new JPanel();
private JPanel LoadSession = new JPanel();
private JPanel LoadList = new JPanel();
private JPanel GraphSub1 = new JPanel();
private JPanel GraphSub2 = new JPanel();
private JPanel GraphSub3 = new JPanel();
private JTabbedPane GraphPanel = new JTabbedPane();
private JButton NewSessBtn = new JButton(); // buttons
private JButton LoadSessBtn = new JButton();
private JButton BackFP = new JButton();
private JButton plusBrand = new JButton();
private JButton minusBrand = new JButton();
private JButton Next = new JButton();
private JLabel EnterBrandLbl = new JLabel(
"Please insert brands for analysis "); // Labels
private JTextField BrandLbl = new JTextField(20); // textfields
public DefaultListModel<String> model = new DefaultListModel<String>
public JList BrandList = new JList(model); // list
private JScrollPane MyScrollPane = new JScrollPane(BrandList);
private CardLayout cardLayout = new CardLayout(); // layouts
private GridBagLayout MyLayout = new GridBagLayout();
GridBagConstraints MyConstr = new GridBagConstraints();
public Gui() {
super("twegraph");
NewSessBtn.setText("New Session"); // button configuration
LoadSessBtn.setText("Load Session");
BackFP.setText("Back");
plusBrand.setText("+");
minusBrand.setText("-");
Next.setText("Next");
actionListener al = new actionListener();
NewSessBtn.addActionListener(al); // add action listeners
LoadSessBtn.addActionListener(al);
BackFP.addActionListener(al);
plusBrand.addActionListener(al);
minusBrand.addActionListener(al);
Next.addActionListener(al);
plusBrand.addActionListener(al);
minusBrand.addActionListener(al);
Container.setLayout(cardLayout); // panels to container+
Container.add(FirstPanel, "FirstPanel");
Container.add(NewSession, "NewSession");
Container.add(LoadSession, "LoadSession");
Container.add(GraphPanel, "GraphPanel");
Container.add(LoadList, "LoadList");
FirstPanel.setLayout(MyLayout); // first panel
MyConstr.gridwidth = 3;
MyConstr.gridheight = 3;
MyConstr.weightx = 1.0;
MyConstr.weighty = 1.0;
MyConstr.ipadx = 100;
MyConstr.ipady = 50;
MyConstr.insets = new Insets(50, 20, 50, 20);
MyConstr.gridx = 1;
MyConstr.gridy = 0;
MyConstr.anchor = GridBagConstraints.NORTH;
MyLayout.setConstraints(NewSessBtn, MyConstr);
FirstPanel.add(NewSessBtn);
MyConstr.gridx = 1;
MyConstr.gridy = 2;
MyConstr.anchor = GridBagConstraints.SOUTH;
MyLayout.setConstraints(LoadSessBtn, MyConstr);
FirstPanel.add(LoadSessBtn);
NewSession.setLayout(MyLayout); // New Session panel
MyConstr.gridwidth = 3;
MyConstr.gridheight = 3;
MyConstr.ipadx = 0; // size
MyConstr.ipady = 0; // size
MyConstr.gridx = 0;
MyConstr.gridy = 2;
MyConstr.insets = new Insets(10, 20, 10, 20);
MyConstr.anchor = GridBagConstraints.SOUTHWEST;
MyLayout.setConstraints(BackFP, MyConstr);
NewSession.add(BackFP);
MyConstr.anchor = GridBagConstraints.SOUTHEAST;
MyLayout.setConstraints(Next, MyConstr);
NewSession.add(Next);
MyConstr.ipadx = 0; // size
MyConstr.ipady = 0; // size
MyConstr.gridx = 0; // place
MyConstr.gridy = 1; // place
MyConstr.insets = new Insets(0, 0, 0, 0);
MyConstr.anchor = GridBagConstraints.PAGE_START;
MyLayout.setConstraints(EnterBrandLbl, MyConstr);
NewSession.add(EnterBrandLbl);
MyConstr.gridx = 0;
MyConstr.gridy = 1;
MyConstr.anchor = GridBagConstraints.CENTER;
MyLayout.setConstraints(BrandLbl, MyConstr);
NewSession.add(BrandLbl);
MyConstr.gridx = 2;
MyConstr.gridy = 1;
MyConstr.anchor = GridBagConstraints.LAST_LINE_START;
MyLayout.setConstraints(plusBrand, MyConstr);
NewSession.add(plusBrand);
MyConstr.gridx = 2;
MyConstr.gridy = 1;
MyConstr.anchor = GridBagConstraints.LAST_LINE_END;
MyLayout.setConstraints(minusBrand, MyConstr);
NewSession.add(minusBrand);
MyConstr.ipadx = 0; // size
MyConstr.ipady = 0;
MyConstr.gridx = 0;
MyConstr.gridy = 1;
MyConstr.anchor = GridBagConstraints.SOUTH;
MyLayout.setConstraints(MyScrollPane, MyConstr);
NewSession.add(MyScrollPane);
GraphPanel.addTab("overall",GraphSub1); //Graph panel
GraphPanel.addTab("tweets/time",GraphSub2);
GraphPanel.addTab("fame",GraphSub3);
this.setContentPane(Container);
cardLayout.show(Container, "FirstPanel");
}
public class actionListener implements ActionListener {
public void actionPerformed(ActionEvent event) {
JButton src = (JButton) event.getSource();
int answer = 0;
if (src.equals(NewSessBtn))
{
answer = JOptionPane.showConfirmDialog(frameYesNo, message);
if (answer == JOptionPane.YES_OPTION) {
cardLayout.show(Container, "NewSession");
try {
DB.flushData();
} catch (SQLException ex) {
Logger.getLogger(Gui.class.getName()).log(Level.SEVERE, null, ex);
}
} else if (answer == JOptionPane.NO_OPTION) {
frameYesNo.dispose();
}
}
if (src.equals(LoadSessBtn)){
cardLayout.show(Container, "LoadSession");
}
if (src.equals(BackFP)){
cardLayout.show(Container, "FirstPanel");
}
if (src.equals(Next)){
cardLayout.show(Container, "GraphPanel");
DB.sendArraytoDB(BrandList);
}
if (src.equals(plusBrand)){
addBrand();
}
if (src.equals(minusBrand))
{
removeBrand();
}
}
}
public void addBrand() {
/*int index = BrandList.getSelectedIndex(); // get selected index
if (index == -1) { // no selection, so insert at beginning
index = 0;
}
else { // add after the selected item
index++;
}*/
String all = "xghxc";
//model.insertElementAt(BrandLbl.getText(), index);
model.addElement(all);
//BrandLbl.setText(null);
}
public void removeBrand() {
int index2 = BrandList.getSelectedIndex();
if (index2 != -1){
model.remove(index2);
}
int size = model.getSize();
if (size == 0) {
minusBrand.setEnabled(false);
} else {
//if (index == model.getSize()) {
//index--;
//}
}
}
}
DB.java
package tweGraf;
import com.mchange.v2.c3p0.ComboPooledDataSource;
import java.sql.*;
import java.util.logging.Level;
import java.util.logging.Logger;
import javax.swing.JList;
/**
*
* @author cheval
*/
public class DB {
static final String JDBC_DRIVER = "com.mysql.jdbc.Driver";
static final String DB_URL = "jdbc:mysql://localhost:3306/twegrahpdb";
static final String USER = "root";
static final String PASS = "Xrt38H0a";
private static ComboPooledDataSource cdps = new ComboPooledDataSource();
public static void MakePool(){
try {
cdps = new ComboPooledDataSource();
cdps.setDriverClass(JDBC_DRIVER);
cdps.setJdbcUrl(DB_URL);
cdps.setUser(USER);
cdps.setPassword(PASS);
cdps.setMaxPoolSize( 50 );
cdps.setMaxStatements(50);
}catch(Exception ex){
System.out.printf("error smth wrong happened");
}
}
public static Connection getConnection() throws SQLException{
return cdps.getConnection();
}
public static void flushData() throws SQLException{
Statement stm = null;
Connection con = null;
try{
con = DB.getConnection();
stm = con.createStatement();
String flushquery1 = "TRUNCATE json_cache";
String flushquery2 = "TRUNCATE tweets";
String flushquery3 = "TRUNCATE tweet_mentions";
String flushquery4 = "TRUNCATE tweet_tags";
String flushquery5 = "TRUNCATE tweet_urls";
String flushquery6 = "TRUNCATE users";
String flushquery7 = "TRUNCATE brand_names";
stm.executeUpdate(flushquery1);
stm.executeUpdate(flushquery2);
stm.executeUpdate(flushquery3);
stm.executeUpdate(flushquery4);
stm.executeUpdate(flushquery5);
stm.executeUpdate(flushquery6);
stm.executeUpdate(flushquery7);
}catch (SQLException e) {
System.out.printf("error executing db clear");
} finally {
if (stm != null){
try{
stm.close();
System.out.printf("statement closed successfuly \n");
} catch (SQLException e){
System.out.printf("error closing statement");
}
}
if (con != null){
try{
con.close();
System.out.printf("connection closed succesfully \n");
} catch (SQLException e){
System.out.printf("error closing connection");
}
}
}
}
public static void sendArraytoDB(JList<String> list){
Connection con = null;
PreparedStatement stm = null;
String updQuery = "insert into brand_names (name) values (?)";
try{
con = DB.getConnection();
//con.setAutoCommit(false);
int x =1;
stm = con.prepareStatement(updQuery);
int f = list.getModel().getSize();
System.out.print(f);
for (int i=0; i<list.getModel().getSize(); i++){
String name =list.getModel().getElementAt(i);
stm.setString(x, name);
//try{
stm.executeUpdate();
//}finally{
//stm.close();
//}
}
}catch(SQLException ex){
System.out.printf("error while sending array to db");
ex.printStackTrace();
}finally{
if (stm != null){
try {
stm.close();
} catch (SQLException ex) {
Logger.getLogger(DB.class.getName()).log(Level.SEVERE, null, ex);
}
}
if (con != null){
try {
con.close();
} catch (SQLException ex) {
Logger.getLogger(DB.class.getName()).log(Level.SEVERE, null, ex);
}
}
}
}
}
如果你仍然不知道，请不要关心我的实际问题，但 仍然 看到关于我的编码风格或技术的错误 post 它
感谢您的宝贵时间
i narrowed the problem to the model since changing the addBrand() method to...
所以这告诉我 addBrand() 方法被调用了多次。
plusBrand.addActionListener(al);
minusBrand.addActionListener(al);
Next.addActionListener(al);
plusBrand.addActionListener(al);
minusBrand.addActionListener(al);
正如您在上面看到的那样，您向按钮添加了两次侦听器。