实现一个字符（包括汉字）的简单互相转换；

package cn.hncu.gui2;import java.awt.Button;import java.awt.Color;import java.awt.FlowLayout;import java.awt.Frame;import java.awt.Label;import java.awt.TextField;import java.awt.event.ActionEvent;import java.awt.event.ActionListener;import java.awt.event.WindowAdapter;import java.awt.event.WindowEvent;public class QueryFrame extends Frame implements ActionListener {
         private TextField tfd1,tfd2;    private Button btnChar,btnUni;    public QueryFrame(String str) {        super(str);        this.setBounds(300,240,300,150);        this.setBackground(Color.LIGHT_GRAY);        this.setLayout(new FlowLayout(FlowLayout.RIGHT));        tfd1 = new TextField("汉字",10);        this.add(new Label("请输入要查询的汉字"));        this.add(tfd1);        tfd2 = new TextField(10);        this.add(new Label("Unicode码值"));        this.add(tfd2);        btnUni =  new Button("查询Unicode码");        btnChar = new Button("查询字符");        this.add(btnUni);        this.add(btnChar);        btnUni.addActionListener(this);        btnChar.addActionListener(this);        this.addWindowListener(new Win2Close());        this.setVisible(true);        }    public static void main(String[] args) {        new QueryFrame("Unicode字符查询器");    }    @Override    public void actionPerformed(ActionEvent e) {        if(e.getSource()==btnUni){            String str = tfd1.getText();            char ch = str.charAt(0);            tfd2.setText(""+(int)ch);        }else   if(e.getSource()==btnChar){            String str = tfd2.getText();                try {                    int n = Integer.parseInt(str);                    tfd1.setText(""+(char)n);                } catch (NumberFormatException e1) {                    tfd1.setText(str+ "不能转换");                }        }    }   }class Win2Close extends WindowAdapter{    @Override    public void windowClosing(WindowEvent e) {        System.exit(0);    }}

正常转换：

异常处理：