班级情况.java

经过调查分析

/*
 * 实验.java
 *
 * Created on 2008年10月18日, 下午4:38
 */

package javaapplication1;
import java.sql.*;
import java.util.*;
import java.awt.*;
import javax.swing.*;
/**
 *
 * @author  mis06
 */
public class 班级情况 extends javax.swing.JPanel {
    
    /** Creates new form 实验 */
    public 班级情况() {
        initComponents();
    }
    
    /** This method is called from within the constructor to
     * initialize the form.
     * WARNING: Do NOT modify this code. The content of this method is
     * always regenerated by the Form Editor.
     */
    // <editor-fold defaultstate="collapsed" desc=" Generated Code ">//GEN-BEGIN:initComponents
    private void initComponents() {
        jLabel1 = new javax.swing.JLabel();
        jComboBox1 = new javax.swing.JComboBox();
        jButton1 = new javax.swing.JButton();
        jScrollPane1 = new javax.swing.JScrollPane();
        jTextArea1 = new javax.swing.JTextArea();

        jLabel1.setText("\u73ed\u7ea7\u540d\u79f0");

        jComboBox1.setModel(new javax.swing.DefaultComboBoxModel(new String[] { "05\u4fe1\u606f\u7ba1\u7406\u4e0e\u4fe1\u606f\u7cfb\u7edf", "05\u5de5\u5546\u7ba1\u7406", "05\u4f1a\u8ba1\u5b66" }));

        jButton1.setText("\u67e5\u8be2");
        jButton1.addActionListener(new java.awt.event.ActionListener() {
            public void actionPerformed(java.awt.event.ActionEvent evt) {
                jButton1ActionPerformed(evt);
            }
        });

        jTextArea1.setColumns(20);
        jTextArea1.setRows(5);
        jScrollPane1.setViewportView(jTextArea1);

        org.jdesktop.layout.GroupLayout layout = new org.jdesktop.layout.GroupLayout(this);
        this.setLayout(layout);
        layout.setHorizontalGroup(
            layout.createParallelGroup(org.jdesktop.layout.GroupLayout.LEADING)
            .add(layout.createSequentialGroup()
                .add(26, 26, 26)
                .add(layout.createParallelGroup(org.jdesktop.layout.GroupLayout.LEADING)
                    .add(layout.createSequentialGroup()
                        .add(jLabel1)
                        .add(13, 13, 13)
                        .add(jComboBox1, org.jdesktop.layout.GroupLayout.PREFERRED_SIZE, 147, org.jdesktop.layout.GroupLayout.PREFERRED_SIZE)
                        .add(30, 30, 30)
                        .add(jButton1))
                    .add(jScrollPane1, org.jdesktop.layout.GroupLayout.PREFERRED_SIZE, 304, org.jdesktop.layout.GroupLayout.PREFERRED_SIZE))
                .addContainerGap(70, Short.MAX_VALUE))
        );
        layout.setVerticalGroup(
            layout.createParallelGroup(org.jdesktop.layout.GroupLayout.LEADING)
            .add(layout.createSequentialGroup()
                .add(21, 21, 21)
                .add(layout.createParallelGroup(org.jdesktop.layout.GroupLayout.BASELINE)
                    .add(jLabel1)
                    .add(jComboBox1, org.jdesktop.layout.GroupLayout.PREFERRED_SIZE, org.jdesktop.layout.GroupLayout.DEFAULT_SIZE, org.jdesktop.layout.GroupLayout.PREFERRED_SIZE)
                    .add(jButton1))
                .addPreferredGap(org.jdesktop.layout.LayoutStyle.RELATED)
                .add(jScrollPane1, org.jdesktop.layout.GroupLayout.PREFERRED_SIZE, 259, org.jdesktop.layout.GroupLayout.PREFERRED_SIZE)
                .addContainerGap(101, Short.MAX_VALUE))
        );
    }// </editor-fold>//GEN-END:initComponents

    private void jButton1ActionPerformed(java.awt.event.ActionEvent evt) {//GEN-FIRST:event_jButton1ActionPerformed
     
     Statement statement;
        String className=new String(jComboBox1.getSelectedItem().toString());
        
        try{
                Connect con=new Connect();
                statement=con.con.createStatement();
                
                StringBuffer results=new StringBuffer();
                
                results.append("班级名称："+className+"\n\n");
                
              String  s="SELECT 专业名称,系名称,学院名称,教工.姓名,学生.姓名,班级人数 FROM 班级,专业,系,学院,教工,学生 WHERE 班级.名称='"+className+"'AND 班级.所属专业编号=专业.专业编号 AND 专业.所属系编号=系编号 AND 专业.所属学院编号=学院编号 AND 班主任编号=教工编号 AND 班长编号=学号";
              ResultSet resultSet=statement.executeQuery(s);
              ResultSetMetaData metaData=resultSet.getMetaData();
              int numberOfColumns=metaData.getColumnCount();
              
              
              while(resultSet.next())
       {  
        for(int i=1;i<=numberOfColumns;i++)
        { 
            if(i==4)
            {results.append("班主任："+resultSet.getObject(i)+"\n");
            results.append("\n");
            }
            else {
            if(i==5)
            {results.append("班长："+resultSet.getObject(i)+"\n");
            results.append("\n");
            }
            else{
            results.append(metaData.getColumnName(i)+"："+resultSet.getObject(i)+"\n");
            results.append("\n");
           }
        }
        }
          }
      
          
          jTextArea1.setText(results.toString());
          jTextArea1.setEditable(false);
        }
        
        
         catch(SQLException sqlException){
        JOptionPane.showMessageDialog(null,sqlException.getMessage(),"Database Error",JOptionPane.ERROR_MESSAGE);
        System.exit(1);}

     catch(ClassNotFoundException classNotFound){
       JOptionPane.showMessageDialog(null,classNotFound.getMessage(),"Driver Not Found",JOptionPane.ERROR_MESSAGE);
        System.exit(1); }
    // TODO add your handling code here:
    }//GEN-LAST:event_jButton1ActionPerformed
    
    
    // Variables declaration - do not modify//GEN-BEGIN:variables
    private javax.swing.JButton jButton1;
    private javax.swing.JComboBox jComboBox1;
    private javax.swing.JLabel jLabel1;
    private javax.swing.JScrollPane jScrollPane1;
    private javax.swing.JTextArea jTextArea1;
    // End of variables declaration//GEN-END:variables
    
}