remaininfoupdate.java

企业物资管理系统 为了使物资管理部门的责、权、利得到落实, 以提高总体的经济效益,采用J2EE 技术体系, 设计与实现了B/S 模式下的企业物资管理系统, 依据开发实例,分析了企业物资管理系统的

//QueryDB.java
import java.sql.*;
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
public class RemainInfoUpdate{
   public RemainInfoUpdate(){
     JFrame myframe=new Update4Frame();
     myframe.setVisible(true);
   }
 }


class Update4Frame extends JFrame{
  public Update4Frame(){
     setTitle("数据库更新");
     setSize(600,300);
     addWindowListener(new WindowAdapter() { 
	public void windowClosing(WindowEvent e) { 
		System.exit(0);
	}
     });
    Container contentpane=getContentPane();
	contentpane.add(new  Update4Panel());
   }
 }

 
  class Update4Panel extends JPanel implements ActionListener {
    private Connection con=null;
    private Statement stmt=null;
    private JTextField sqlcommand;
    private JButton submit;
    private JTextArea  resultarea;
    private ResultSet rs=null;
 
    public Update4Panel()
   {
     sqlcommand=new JTextField(30);
     resultarea=new JTextArea(10,30);
     resultarea.setEditable(false);
     submit=new JButton("提交");
     add(new JLabel("SQL更新语句:"));
     add(sqlcommand);
     add(submit);
     add(new JLabel ("当前数据表RemainInformation中的记录"));
     JScrollPane scrollpane=new JScrollPane(resultarea);
     add(scrollpane);
     submit.addActionListener(this);
 System.out.println("hello");
    try{
   String url ="jdbc:microsoft:sqlserver://localhost:1433;DatabaseName=BasicInfo";
 			String driverName = "com.microsoft.jdbc.sqlserver.SQLServerDriver";
      Class.forName(driverName).newInstance();
       //与SQL sever下的BasicInfo数据库的连接
      con=DriverManager.getConnection(url,"SA","");
      System.out.println("已连接到数据库");
      stmt=con.createStatement();
      //showTable();   //出错
       }catch(Exception ex) {
         System.out.println(ex.getMessage());
          return;
       }
   }



 public void showTable(){
   try{
     rs=stmt.executeQuery("SELECT * FROM RemainInformation");
     resultarea.setText("名称");
     for(int i=1;i<(30-2*"名称".length());i++)
      resultarea.append(" ");
      resultarea.append("剩余数量"+"\n");
     while(rs.next())
      {
        String sname =rs.getString("名称");
        resultarea.append(sname);
        int length=sname.length();
        //按照不同姓名的长度，输出相应个数的空格以使后面的名称列能够对齐
        for(int i=1;i<=(30-2*length);i++) resultarea.append(" ");
         resultarea.append(rs.getString("剩余数量")+"\n"); //输出名称
      }
     } catch(Exception ex){
       System.out.println(ex.getMessage());
     }
  }

 public void actionPerformed(ActionEvent evt)
  {
     try{
     String command=sqlcommand.getText();
     //注意这里必须进行编码转换，否则更新数据表中的中文列时会出现乱码！
     //command=new String(command.getBytes(),"ISO-8859-1");
     stmt.execute(command);
     showTable();
        } catch(Exception ex){
     System.out.println(ex.getMessage());
      }
  }
 }