为什么System.exit(-1)前面这条语句执行没有效果呢？ - 黑马程序员技术交流社区

import java.awt.BorderLayout;
import java.awt.Container;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JPanel;
import javax.swing.JScrollPane;
import javax.swing.JTextArea;
import javax.swing.JTextField;
/*
* 使用预编译的SQL语句查询access数据库
*/
public class PrepareQuery extends JFrame implements ActionListener {
private static final long serialVersionUID = 1L;
JLabel jlName = new JLabel("姓名");
JTextField tfName = new JTextField();
JButton jbQuery = new JButton("查询");
JTextArea taInfo = new JTextArea();
JScrollPane pane = new JScrollPane();
JPanel panel = new JPanel();
public PrepareQuery() {
super("执行预编译语句");
setSize(350, 260);
this.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
panel.setLayout(new BorderLayout());
panel.add(jlName, BorderLayout.WEST);
panel.add(tfName, BorderLayout.CENTER);
panel.add(jbQuery, BorderLayout.EAST);
jbQuery.addActionListener(this);
pane.getViewport().add(taInfo);
Container container = this.getContentPane();
container.setLayout(new BorderLayout());
container.add(panel, BorderLayout.NORTH);
container.add(pane, BorderLayout.CENTER);
}
//使用预编译SQL语句查询数据库
public void getRecord() {
try {
//加载驱动程序
Class.forName("sun.jdbc.odbc.JdbcOdbcDriver");
} catch (ClassNotFoundException e1) {
taInfo.setText("无法加载jdbc驱动程序");
try {
Thread.sleep(5000);
} catch (InterruptedException e) {
e.printStackTrace();
}
System.exit(-1);
}
Connection con = null;
try {
String url = "jdbc:odbc:Students";
con = DriverManager.getConnection(url);
String sql = "select * from student where s_name = ?";
PreparedStatement preSt = con.prepareStatement(sql);
String name = tfName.getText().trim();
preSt.setString(1, name);
ResultSet rs = preSt.executeQuery();
//判断结果集是否有结果，有的话显示结果集
if (rs.next() == false) {
taInfo.setText("没有找到符合要求的记录");
} else {
do {
taInfo.append(rs.getInt(1) + "\t");
taInfo.append(rs.getString(2) + "\t");
taInfo.append(rs.getString(3) + "\t");
taInfo.append(rs.getString(4) + "\t");
taInfo.append(rs.getInt(5) + "\n");
} while (rs.next());
}
rs.close();
preSt.close();
} catch (SQLException e) {
taInfo.setText(e.getMessage());
} finally {
try {
con.close();
} catch (SQLException e) {
taInfo.setText(e.getMessage());
}
}
}
public static void main(String[] args) {
PrepareQuery frame = new PrepareQuery();
frame.setVisible(true);
}
//查询按钮动作
public void actionPerformed(ActionEvent e) {
taInfo.setText("");
if (e.getSource() == jbQuery) {
this.getRecord();
}
}
}

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