补充代码

package cn.tted.ChatBox;import java.awt.Button;import java.awt.Component;import java.awt.EventQueue;import java.awt.Graphics;import java.awt.Graphics2D;import java.awt.Rectangle;import java.awt.TexturePaint;import java.awt.event.ActionEvent;import java.awt.event.ActionListener;import java.awt.image.BufferedImage;import java.io.File;import java.io.IOException;import java.net.InetAddress;import java.net.Socket;import java.net.UnknownHostException;import javax.imageio.ImageIO;import javax.swing.ImageIcon;import javax.swing.JFrame;import javax.swing.JLabel;import javax.swing.JPanel;import javax.swing.JTextField;public class SignIn {public static void main(String[] args){EventQueue.invokeLater(new Runnable(){public void run(){new SignInFrame();}});}}class SignInFrame extends JFrame{public SignInFrame(){setTitle(TITLE);setBounds(300,200,DEFAULT_WIDTH,DEFAULT_HEIGHT);setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);setResizable(false);setVisible(true);setLayout(null);panelSignIn = new JPanel();panelButton = new JPanel();textSignIn = new JTextField(10);buttonSignIn = new Button("SignIn");//textSignIn.setLocation(180, 190);//buttonSignIn.setLocation(220,190);buttonSignIn.addActionListener(new ButtonListener());JLabel lbBg;/** 加入背景图片 */lbBg = new JLabel(new ImageIcon("F:\\bg.jpg"));lbBg.setBounds(0, 0, 500, 400);panelSignIn.add(textSignIn);//panelSignIn.add(buttonSignIn);panelButton.add(buttonSignIn);panelSignIn.setBounds(148, 186,120,32);panelButton.setBounds(286,186,60,32);add(panelSignIn);add(panelButton);add(lbBg);}class ButtonListener implements ActionListener{@Overridepublic void actionPerformed(ActionEvent e) {if(e.getSource() == buttonSignIn){name = textSignIn.getText();try{new ChatFrame(name, new Socket(InetAddress.getLocalHost(),4800));} catch (UnknownHostException e1){e1.printStackTrace();} catch (IOException e1) {e1.printStackTrace();}SignInFrame.this.setVisible(false);}}}private static final long serialVersionUID = -8649115223425727109L;JPanel panelSignIn;JPanel panelButton;JTextField textSignIn;JLabel jLabel;Button buttonSignIn;String name;static final String TITLE = "用户登录";static final int DEFAULT_WIDTH = 514;static final int DEFAULT_HEIGHT = 436;public class PicPanel extends JPanel{ private static final long serialVersionUID = 1L;BufferedImage img; public PicPanel(String path) {  super();  try  {   img = ImageIO.read(new File(path));  }  catch (Exception e)  {   System.out.println("Error: "+e.toString());  }  } public void paintComponent(Graphics g)//绘制图片的方法 {  try  {   Rectangle rect = new Rectangle(0,0,img.getWidth(null),img.getHeight(null));   TexturePaint texture = new TexturePaint(img,rect);   Graphics2D g2 = (Graphics2D)g;   g2.setPaint(texture);   g2.fillRect(0,0,this.getWidth(),this.getHeight());   super.paintComponent(g);  }  catch(Exception e)  {   System.out.println("Error: "+e.toString());  } } public void setImage(String path)//更换图片的方法 {  try  {   img = ImageIO.read(new File(path));this.repaint();  }  catch (Exception e)  {   System.out.println("Error: "+e.toString());  }  }}}