用java设计一个客户管理系统过程中,Database这个类是我连接数据库程序的类,在设计客户基本信息这个表的时候,我想初始化三个客户的信息,于是我在Database这个类中加入了三条语句
public static boolean joinDB() {
boolean joinFlag;
try {
joinFlag = true;
Class.forName("com.microsoft.jdbc.sqlserver.SQLServerDriver");
cn = DriverManager.getConnection("jdbc:microsoft:sqlserver://localhost:1433;DatabaseName=sample","sa","605");
cn.setCatalog("sample");
System.out.println("数据库连接成功");
st = cn.createStatement(ResultSet.TYPE_SCROLL_SENSITIVE,
ResultSet.CONCUR_READ_ONLY);
st.execute("INSERT INTO Table3 VALUES ('admin','123')");
st.execute("INSERT INTO Clientm VALUES ('张三','男','23')");
st.execute("INSERT INTO Clientm VALUES ('李四','女','25')");
st.execute("INSERT INTO Clientm VALUES ('王五','男','20')");
就是这最后的三条,Land这个类中用到了joinDB()这个方法,Land这个类是整个程序的主程序,可是每次我运行程序,客户基本信息中就加三天 张三 李四 王五,总是这样的循环。是不是不应该在Database这个类中执行添加数据库的操作啊,如果不是,应该在哪添加
st.execute("INSERT INTO Clientm VALUES ('张三','男','23')");
st.execute("INSERT INTO Clientm VALUES ('李四','女','25')");
st.execute("INSERT INTO Clientm VALUES ('王五','男','20')");
这个表的信息啊!!
public static boolean joinDB() {
boolean joinFlag;
try {
joinFlag = true;
Class.forName("com.microsoft.jdbc.sqlserver.SQLServerDriver");
cn = DriverManager.getConnection("jdbc:microsoft:sqlserver://localhost:1433;DatabaseName=sample","sa","605");
cn.setCatalog("sample");
System.out.println("数据库连接成功");
st = cn.createStatement(ResultSet.TYPE_SCROLL_SENSITIVE,
ResultSet.CONCUR_READ_ONLY);
st.execute("INSERT INTO Table3 VALUES ('admin','123')");
st.execute("INSERT INTO Clientm VALUES ('张三','男','23')");
st.execute("INSERT INTO Clientm VALUES ('李四','女','25')");
st.execute("INSERT INTO Clientm VALUES ('王五','男','20')");
就是这最后的三条,Land这个类中用到了joinDB()这个方法,Land这个类是整个程序的主程序,可是每次我运行程序,客户基本信息中就加三天 张三 李四 王五,总是这样的循环。是不是不应该在Database这个类中执行添加数据库的操作啊,如果不是,应该在哪添加
st.execute("INSERT INTO Clientm VALUES ('张三','男','23')");
st.execute("INSERT INTO Clientm VALUES ('李四','女','25')");
st.execute("INSERT INTO Clientm VALUES ('王五','男','20')");
这个表的信息啊!!
楼主【beingyourself】截止到2008-07-21 23:19:27的历史汇总数据(不包括此帖):
发帖的总数量:52 发帖的总分数:1100 每贴平均分数:21
回帖的总数量:14 得分贴总数量:0 回帖的得分率:0%
结贴的总数量:52 结贴的总分数:1100
无满意结贴数:4 无满意结贴分:50
未结的帖子数:0 未结的总分数:0
结贴的百分比:100.00% 结分的百分比:100.00%
无满意结贴率:7.69 % 无满意结分率:4.55 %
敬礼!
怎么可能死循环呢?
怎么可能死循环呢?
import java.awt.event.*;
import javax.swing.*;
import java.sql.*;
import javax.swing.*;
public class Land
{
public static void main(String[] args)
{
LandFrame frame=new LandFrame();
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setVisible(true);
}
}
class LandFrame extends JFrame
{
JFrame jf ;
JLabel labelWelcome = new JLabel("小区车辆管理系统");
JLabel labelName=new JLabel("用户名:");
JLabel labelPassword=new JLabel("密码:");
JTextField textName=new JTextField();
JPasswordField textPassword=new JPasswordField();
JButton buttonEnter=new JButton("登录");
JButton buttoncancel=new JButton("清空");
public LandFrame()
{
jf=this;
Toolkit kit=Toolkit.getDefaultToolkit();
Dimension screenSize=kit.getScreenSize();
int screenWidth=screenSize.width;
int screenHeight=screenSize.height;
setSize(screenWidth/4,screenHeight/4);
setLocation(screenWidth*3/8,screenHeight*3/8);
setTitle("登陆界面");
Font f = new Font("新宋体",Font.PLAIN,12);
Container con = getContentPane();
con.setLayout(null);
labelWelcome.setBounds(95,10,150,20);
labelWelcome.setFont(new Font("新宋体",Font.PLAIN,14));
con.add(labelWelcome);
labelName.setBounds(45,40,55,20);
labelName.setFont(f);
con.add(labelName);
textName.setBounds(95,40,120,20);
con.add(textName);
labelPassword.setBounds(45,70,45,20);
labelPassword.setFont(f);
con.add(labelPassword);
textPassword.setBounds(95,70,120,20);
con.add(textPassword);
buttonEnter.setBounds(90,110,60,20);
buttonEnter.setFont(f);
con.add(buttonEnter);
buttonEnter.addMouseListener(new MouseAdapter(){
public void mouseClicked(MouseEvent m){
if(textName.getText().equals("")){
new JOptionPane().showMessageDialog(null,"用户名不能为空!");
}
else if(textPassword.getText().equals("")){
new JOptionPane().showMessageDialog(null,"密码不能为空!");
}
else{
String sql="select * from Table3 where User_Name = '" + textName.getText() + "' and Password = '" + textPassword.getText()+ "'";
System.out.println(sql);
Judge(sql);
}
}
});
buttoncancel.setBounds(155,110,60,20);
buttoncancel.setFont(f);
con.add(buttoncancel);
buttoncancel.addMouseListener(new MouseAdapter(){
public void mouseClicked(MouseEvent m){
textName.setText("");
textPassword.setText("");
}
});
}
private void Judge(String sqlString) { if (Database.joinDB()) {
if (Database.query(sqlString))
try{
if(Database.rs.isBeforeFirst()) {
System.out.println("密码正确");
jf.setVisible(false);
Database.cn.close();
new Main();
}
else {
System.out.println("错误");
new JOptionPane().showMessageDialog(null,"用户名或密码错误!","",JOptionPane.ERROR_MESSAGE);
}
}catch(Exception e) {
System.out.println(e.getMessage());
}
}
else{
System.out.println("连接数据库不成功!!!");
}
}
}
private Connection con;
public DBManager() {
openConn();
} private void openConn() {
try {
if (con == null || con.isClosed()) {
Class.forName("com.microsoft.jdbc.sqlserver.SQLServerDriver");
con = DriverManager.getConnection(
"jdbc:microsoft:sqlserver://localhost:1433;dataBaseName=",
"sa", "");
}
} catch (SQLException ex) {
ex.printStackTrace();
} catch (ClassNotFoundException ex) {
ex.printStackTrace();
}
}
public int executeSQL(String sql) {
int flag = 0;
try {
Statement stmt = con.createStatement();
flag = stmt.executeUpdate(sql);
} catch (SQLException ex) {
ex.printStackTrace();
} finally {
closeConn();
}
return flag;
}