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Question

把当前目录改变到:\javaclass下面或者把c:\javaclass放到你的classpath里(在jdk1.3一下的版本中也要把当前目录加入classpath中,然后 javac Namepass.java 成功的话
java Namepass     (注意大小写)

Answer 1

把当前目录改变到:\javaclass下面或者把c:\javaclass放到你的classpath里(在jdk1.3一下的版本中也要把当前目录加入classpath中,然后 javac Namepass.java 成功的话
java Namepass     (注意大小写)

Answer 2

import java.awt.*;
import javax.swing.*;
import java.awt.event.*;
import java.sql.*;public  class NamePass extends JFrame implements ActionListener
{
  JLabel label1=    new JLabel("Name:",JLabel.LEFT);
  JTextField tfname= new JTextField();
  JLabel label2=    new JLabel("Password:",JLabel.LEFT);
  JTextField tfpass= new JPasswordField();
  JButton OKB=      new JButton("OK");
  JButton APPLYB=    new JButton("APPLY");
  JButton RESETB=    new JButton("RESET");
  JButton SHOWSTATEB=new JButton("STATE");  //final static int    ID_BUTTON_OK = 555550;
  //final static int    ID_BUTTON_APPLY = 555551;
  final static int    ID_BUTTON_RESET = 555551;
  //final static int    ID_BUTTON_STATE= 555553;
    
public void actionPerformed(ActionEvent event)
{
    switch(event.getID())
    {
        case ID_BUTTON_RESET:         
RESETB_ActionPerformed();
break;
        //case ID_BUTTON_OK:
  // OKB_ActionPerformed();
  // break;
        //case ID_BUTTON_APPLY:         
  // APPLYB_ActionPerformed();
  // break;
      // case ID_BUTTON_STATE:
    //SHOWSTATEB_ActionPerformed();
  // break;
}
}
    
void RESETB_ActionPerformed()
{
// to do: code goes here.
        tfname.setText(null);
tfpass.setText(null);}
void buildConstraints(GridBagConstraints gbc,int gx,
                    int gy,int gw,int gh,int wx,int wy)
{
        gbc.gridx=gx;
        gbc.gridy=gy;
        gbc.gridwidth=gw;
        gbc.gridheight=gh;
        gbc.weightx=wx;
        gbc.weighty=wy;
}
      
    public NamePass() 
    {
        super("Welcome");
        setSize(400,200);
        GridBagLayout gridbag=new GridBagLayout();
        GridBagConstraints constraints=new GridBagConstraints();
        JPanel pane=new JPanel();
        pane.setLayout(gridbag);
    
//................name label
        buildConstraints(constraints,0,0,1,1,30,40);  
        constraints.fill=GridBagConstraints.NONE;
        constraints.anchor=GridBagConstraints.EAST;
        
        gridbag.setConstraints(label1,constraints);
        pane.add(label1);
//................name text field
        buildConstraints(constraints,1,0,1,1,70,0);  
        constraints.fill=GridBagConstraints.HORIZONTAL;
        
        gridbag.setConstraints(tfname,constraints);
        pane.add(tfname);
//................password label
        buildConstraints(constraints,0,1,1,1,0,40);  
        constraints.fill=GridBagConstraints.NONE;
        constraints.anchor=GridBagConstraints.EAST;
        
        gridbag.setConstraints(label2,constraints);
        pane.add(label2);
//................password text field
        buildConstraints(constraints,1,1,1,1,0,0);  
        constraints.fill=GridBagConstraints.HORIZONTAL;
        
        gridbag.setConstraints(tfpass,constraints);
        pane.add(tfpass);//................ok button
        buildConstraints(constraints,0,2,1,1,0,20);  
        constraints.fill=GridBagConstraints.NONE;
        constraints.anchor=GridBagConstraints.EAST;
        
        gridbag.setConstraints(OKB,constraints);
        pane.add(OKB);
//................apply button
        buildConstraints(constraints,1,2,1,1,0,0);  
        constraints.fill=GridBagConstraints.NONE;
        constraints.anchor=GridBagConstraints.CENTER;
        
        gridbag.setConstraints(APPLYB,constraints);
        pane.add(APPLYB);//................reset button
        buildConstraints(constraints,0,3,1,1,0,20);  
        constraints.fill=GridBagConstraints.NONE;
        constraints.anchor=GridBagConstraints.EAST;
        
        gridbag.setConstraints(RESETB,constraints);
        pane.add(RESETB);
//................showstate button
        buildConstraints(constraints,1,3,1,1,0,0);  
        constraints.fill=GridBagConstraints.NONE;
        constraints.anchor=GridBagConstraints.CENTER;
        
        gridbag.setConstraints(SHOWSTATEB,constraints);
        pane.add(SHOWSTATEB);
        
        
        RESETB.addActionListener(this);
        OKB.addActionListener(this);
        APPLYB.addActionListener(this);
        SHOWSTATEB.addActionListener(this);
        setContentPane(pane);
        
}      public static void main(String[] arguments) {
            NamePass frame=new NamePass();
        db mysql=new db();  
        try{ 
              mysql.st=mysql.con.createStatement(); 
              mysql.rs=mysql.st.executeQuery("insert into namepass(name,password) values('panda','go');");
              System.out.println(mysql.rs.getString(1));                    
    
          } catch (SQLException E) 
              {
                System.out.println("SQLException: " + E.getMessage());
                System.out.println("SQLState:    " + E.getSQLState());
                System.out.println("VendorError:  " + E.getErrorCode());
                }  
  //  ExitWindow exit=new ExitWindow();
    //frame.addWindowListerner(exit);
    frame.show();
}  }  
class db
{ 
        
        Connection con; 
        Statement st; 
        ResultSet rs; 
                
        db() 
        {
          try
          { 
            Class.forName("org.gjt.mm.mysql.Driver").newInstance(); 
      
            //加载 mm.mysql.driver 
            con=DriverManager.getConnection("jdbc:mysql://localhost:3306/test","root","780318");
            //创建数据库联接 
          } 
          catch (Exception R) 
          {
            System.err.println("Unable to load driver.");
            R.printStackTrace();
    
           }
         }    
} 

Answer 3

好了import java.awt.*;
import javax.swing.*;
import java.awt.event.*;
import java.sql.*;
public  class NamePass extends JFrame implements ActionListener{
  JLabel label1=    new JLabel("Name:",JLabel.LEFT);
  JTextField tfname= new JTextField();
  JLabel label2=    new JLabel("Password:",JLabel.LEFT);
  JTextField tfpass= new JPasswordField();
  JButton OKB=      new JButton("OK");
  JButton APPLYB=    new JButton("APPLY");
  JButton RESETB=    new JButton("RESET");
  JButton SHOWSTATEB=new JButton("STATE");  //final static int    ID_BUTTON_OK = 555550;
  //final static int    ID_BUTTON_APPLY = 555551;
  final static int    ID_BUTTON_RESET = 555551;
  //final static int    ID_BUTTON_STATE= 555553;public void actionPerformed(ActionEvent event)
{
    switch(event.getID())
    {
        case ID_BUTTON_RESET:
RESETB_ActionPerformed();
break;
        //case ID_BUTTON_OK:
  // OKB_ActionPerformed();
  // break;
        //case ID_BUTTON_APPLY:
  // APPLYB_ActionPerformed();
  // break;
      // case ID_BUTTON_STATE:
    //SHOWSTATEB_ActionPerformed();
  // break;
}
}void RESETB_ActionPerformed()
{
// to do: code goes here.
        tfname.setText(null);
tfpass.setText(null);
        }
void buildConstraints(GridBagConstraints gbc,int gx,
                    int gy,int gw,int gh,int wx,int wy) {
        gbc.gridx=gx;
        gbc.gridy=gy;
        gbc.gridwidth=gw;
        gbc.gridheight=gh;
        gbc.weightx=wx;
        gbc.weighty=wy;}    public NamePass() {
        super("Welcome");
        setSize(400,200);
        GridBagLayout gridbag=new GridBagLayout();
        GridBagConstraints constraints=new GridBagConstraints();
        JPanel pane=new JPanel();
        pane.setLayout(gridbag);//................name label
        buildConstraints(constraints,0,0,1,1,30,40);
        constraints.fill=GridBagConstraints.NONE;
        constraints.anchor=GridBagConstraints.EAST;        gridbag.setConstraints(label1,constraints);
        pane.add(label1);
//................name text field
        buildConstraints(constraints,1,0,1,1,70,0);
        constraints.fill=GridBagConstraints.HORIZONTAL;        gridbag.setConstraints(tfname,constraints);
        pane.add(tfname);
//................password label
        buildConstraints(constraints,0,1,1,1,0,40);
        constraints.fill=GridBagConstraints.NONE;
        constraints.anchor=GridBagConstraints.EAST;        gridbag.setConstraints(label2,constraints);
        pane.add(label2);
//................password text field
        buildConstraints(constraints,1,1,1,1,0,0);
        constraints.fill=GridBagConstraints.HORIZONTAL;        gridbag.setConstraints(tfpass,constraints);
        pane.add(tfpass);//................ok button
        buildConstraints(constraints,0,2,1,1,0,20);
        constraints.fill=GridBagConstraints.NONE;
        constraints.anchor=GridBagConstraints.EAST;        gridbag.setConstraints(OKB,constraints);
        pane.add(OKB);
//................apply button
        buildConstraints(constraints,1,2,1,1,0,0);
        constraints.fill=GridBagConstraints.NONE;
        constraints.anchor=GridBagConstraints.CENTER;        gridbag.setConstraints(APPLYB,constraints);
        pane.add(APPLYB);//................reset button
        buildConstraints(constraints,0,3,1,1,0,20);
        constraints.fill=GridBagConstraints.NONE;
        constraints.anchor=GridBagConstraints.EAST;        gridbag.setConstraints(RESETB,constraints);
        pane.add(RESETB);
//................showstate button
        buildConstraints(constraints,1,3,1,1,0,0);
        constraints.fill=GridBagConstraints.NONE;
        constraints.anchor=GridBagConstraints.CENTER;        gridbag.setConstraints(SHOWSTATEB,constraints);
        pane.add(SHOWSTATEB);
        RESETB.addActionListener(this);
        OKB.addActionListener(this);
        APPLYB.addActionListener(this);
        SHOWSTATEB.addActionListener(this);        setContentPane(pane);
}
//}    public static void main(String[] arguments) {
        NamePass frame=new NamePass();
        db mysql = new db();
        try{
              mysql.st=mysql.con.createStatement();
              mysql.rs=mysql.st.executeQuery("insert into namepass(name,password) values('panda','go');");
              System.out.println(mysql.rs.getString(1));          } catch (SQLException E)
              {
                System.out.println("SQLException: " + E.getMessage());
                System.out.println("SQLState:    " + E.getSQLState());
                System.out.println("VendorError:  " + E.getErrorCode());
                }
    //ExitWindow exit = new ExitWindow();
    //frame.addWindowListerner(exit);
    frame.show();
}
}class db{        Connection con;
        Statement st;
        ResultSet rs;        db() {
          try{
          Class.forName("org.gjt.mm.mysql.Driver").newInstance();            //加载 mm.mysql.driver
          con=DriverManager.getConnection("jdbc:mysql://localhost:3306/test","root","780318");
            //创建数据库联接
          } catch (Exception R)
            {
            System.err.println("Unable to load driver.");
            R.printStackTrace();            } }
}

Answer 4

括号对了还有问题呀
c:\javaclass\namepass.java:196: 'class' or 'interface' expected
    public static void main(String[] arguments) {
                  ^
1 error

Answer 5

请把hexiaofeng(java爱好者)或我的代码粘下来编译一下试一试，应该不会有问题。你原来的代码确实是括号的问题，将db.class提出来作为一个独立的class，而main方法属于NamePass.class。原来你写浑了

Answer 6

import java.awt.*;
import javax.swing.*;
import java.awt.event.*;
import java.sql.*;public  class NamePass extends JFrame implements ActionListener{
  JLabel label1=    new JLabel("Name:",JLabel.LEFT);
  JTextField tfname= new JTextField();
  JLabel label2=    new JLabel("Password:",JLabel.LEFT);
  JTextField tfpass= new JPasswordField();
  JButton OKB=      new JButton("OK");
  JButton APPLYB=    new JButton("APPLY");
  JButton RESETB=    new JButton("RESET");
  JButton SHOWSTATEB=new JButton("STATE");  //final static int    ID_BUTTON_OK = 555550;
  //final static int    ID_BUTTON_APPLY = 555551;
  final static int    ID_BUTTON_RESET = 555551;
  //final static int    ID_BUTTON_STATE= 555553;
    
public void actionPerformed(ActionEvent event)
{
    switch(event.getID())
    {
        case ID_BUTTON_RESET:         
RESETB_ActionPerformed();
break;
        //case ID_BUTTON_OK:
  // OKB_ActionPerformed();
  // break;
        //case ID_BUTTON_APPLY:         
  // APPLYB_ActionPerformed();
  // break;
      // case ID_BUTTON_STATE:
    //SHOWSTATEB_ActionPerformed();
  // break;
}
}
    
void RESETB_ActionPerformed()
{
// to do: code goes here.
    tfname.setText(null);
tfpass.setText(null);
}
void buildConstraints(GridBagConstraints gbc,int gx,
                    int gy,int gw,int gh,int wx,int wy) {
        gbc.gridx=gx;
        gbc.gridy=gy;
        gbc.gridwidth=gw;
        gbc.gridheight=gh;
        gbc.weightx=wx;
        gbc.weighty=wy;
}    
    public NamePass() {
        super("Welcome");
        setSize(400,200);
        GridBagLayout gridbag=new GridBagLayout();
        GridBagConstraints constraints=new GridBagConstraints();
        JPanel pane=new JPanel();
        pane.setLayout(gridbag);
    
//................name label
        buildConstraints(constraints,0,0,1,1,30,40);  
        constraints.fill=GridBagConstraints.NONE;
        constraints.anchor=GridBagConstraints.EAST;
        
        gridbag.setConstraints(label1,constraints);
        pane.add(label1);
//................name text field
        buildConstraints(constraints,1,0,1,1,70,0);  
        constraints.fill=GridBagConstraints.HORIZONTAL;
        
        gridbag.setConstraints(tfname,constraints);
        pane.add(tfname);
//................password label
        buildConstraints(constraints,0,1,1,1,0,40);  
        constraints.fill=GridBagConstraints.NONE;
        constraints.anchor=GridBagConstraints.EAST;
        
        gridbag.setConstraints(label2,constraints);
        pane.add(label2);
//................password text field
        buildConstraints(constraints,1,1,1,1,0,0);  
        constraints.fill=GridBagConstraints.HORIZONTAL;
        
        gridbag.setConstraints(tfpass,constraints);
        pane.add(tfpass);//................ok button
        buildConstraints(constraints,0,2,1,1,0,20);  
        constraints.fill=GridBagConstraints.NONE;
        constraints.anchor=GridBagConstraints.EAST;
        
        gridbag.setConstraints(OKB,constraints);
        pane.add(OKB);
//................apply button
        buildConstraints(constraints,1,2,1,1,0,0);  
        constraints.fill=GridBagConstraints.NONE;
        constraints.anchor=GridBagConstraints.CENTER;
        
        gridbag.setConstraints(APPLYB,constraints);
        pane.add(APPLYB);//................reset button
        buildConstraints(constraints,0,3,1,1,0,20);  
        constraints.fill=GridBagConstraints.NONE;
        constraints.anchor=GridBagConstraints.EAST;
        
        gridbag.setConstraints(RESETB,constraints);
        pane.add(RESETB);
//................showstate button
        buildConstraints(constraints,1,3,1,1,0,0);  
        constraints.fill=GridBagConstraints.NONE;
        constraints.anchor=GridBagConstraints.CENTER;
        
        gridbag.setConstraints(SHOWSTATEB,constraints);
        pane.add(SHOWSTATEB);
        
        
        RESETB.addActionListener(this);
        OKB.addActionListener(this);
        APPLYB.addActionListener(this);
        SHOWSTATEB.addActionListener(this);
        setContentPane(pane);
        
}    public static void main(String[] arguments) {
            NamePass frame=new NamePass();
        db mysql=new db();  
        try{ 
              mysql.st=mysql.con.createStatement(); 
              mysql.rs=mysql.st.executeQuery("insert into namepass(name,password) values('panda','go');");
              System.out.println(mysql.rs.getString(1));                    
    
          } catch (SQLException E) 
              {
                System.out.println("SQLException: " + E.getMessage());
                System.out.println("SQLState:    " + E.getSQLState());
                System.out.println("VendorError:  " + E.getErrorCode());
                }  
//    ExitWindow exit=new ExitWindow();
    //frame.addWindowListerner(exit);
    frame.show();
}  
}  
class db{ 
        
        Connection con; 
        Statement st; 
        ResultSet rs; 
                
        public db() 
{
          try
{ 
           Class.forName("org.gjt.mm.mysql.Driver").newInstance(); 
      
            //加载 mm.mysql.driver 
          con=DriverManager.getConnection("jdbc:mysql://localhost:3306/test","root","780318");
            //创建数据库联接 
           } catch (Exception R) 
            {
            System.err.println("Unable to load driver.");
            R.printStackTrace();
    
            } 
}    
} 主要是你把main()方法写在了NamePass这个类的外面。
同时你没有定义ExitWindow