JAVA基础复习资料

import java.net.*; import java.io.*; import java.awt.*; import java.awt.event.*; import javax.swing.*; class Client extends JFrame implements Runnable,ActionListener { JButton connection,computer; JTextField inputA,inputB,inputC; JTextArea showResult; Socket socket=null; DataInputStream in=null; DataOutputStream out=null; Thread thread; public Client() { socket=new Socket(); //待连接的套接字。 connection=new JButton("连接服务器"); computer=new JButton("求方程的根"); computer.setEnabled(false); //没有和服务器连接之前,该按钮不可用。 inputA=new JTextField("0",12); inputB=new JTextField("0",12); inputC=new JTextField("0",12); Box boxV1=Box.createVerticalBox(); boxV1.add(new JLabel("输入2次项系数")); boxV1.add(new JLabel("输入1次项系数")); boxV1.add(new JLabel("输入常数项")); Box boxV2=Box.createVerticalBox(); boxV2.add(inputA); boxV2.add(inputB); boxV2.add(inputC); Box baseBox=Box.createHorizontalBox(); baseBox.add(boxV1); baseBox.add(boxV2); Container con=getContentPane(); con.setLayout(new FlowLayout()); showResult=new JTextArea(8,18); con.add(connection); con.add(baseBox); con.add(computer); con.add(new JScrollPane(showResult)); computer.addActionListener(this); connection.addActionListener(this); thread = new Thread(this); setBounds(100,100,360,310); setVisible(true); setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); } public void run() { while(true) { try{ double root1=in.readDouble(); //堵塞状态，除非读取到信息。 double root2=in.readDouble(); showResult.append("\n两个根:\n"+root1+"\n"+root2); showResult.setCaretPosition((showResult.getText()).length()); } catch(IOException e) { showResult.setText("与服务器已断开"); computer.setEnabled(false); break; } } } public void actionPerformed(ActionEvent e) { if(e.getSource()==connection) { try { //请求和服务器建立套接字连接： if(socket.isConnected()) { } else { InetAddress address=InetAddress.getByName("127.0.0.1"); InetSocketAddress socketAddress=new InetSocketAddress(address,4331); socket.connect(socketAddress); in =new DataInputStream(socket.getInputStream()); out = new DataOutputStream(socket.getOutputStream()); computer.setEnabled(true); thread.start(); } } catch (IOException ee){} } if(e.getSource()==computer) { try { double a=Double.parseDouble(inputA.getText()), b=Double.parseDouble(inputB.getText()), c=Double.parseDouble(inputC.getText()); double disk=b*b-4*a*c; if(disk>=0) { out.writeDouble(a); out.writeDouble(b); out.writeDouble(c); } else { inputA.setText("此2次方程无实根"); } } catch(Exception ee) { inputA.setText("请输入数字字符"); } } } public static void main(String args[]) { Client win=new Client(); } } (2) 服务器端程序 import java.io.*; import java.net.*; import java.util.*; public class Server { public static void main(String args[]) { ServerSocket server=null; ServerThread thread; Socket you=null; while(true) { try{ server=new ServerSocket(4331); } catch(IOException e1) { System.out.println("正在监听"); //ServerSocket对象不能重复创建。 } try{ you=server.accept(); System.out.println("客户的地址:"+you.getInetAddress()); } catch (IOException e) { System.out.println("正在等待客户"); } if(you!=null) { new ServerThread(you).start(); //为每个客户启动一个专门的线程。 } else { continue; } } } } class ServerThread extends Thread { Socket socket; DataOutputStream out=null; DataInputStream in=null; String s=null; ServerThread(Socket t) { socket=t; try { in=new DataInputStream(socket.getInputStream()); out=new DataOutputStream(socket.getOutputStream()); } catch (IOException e) {} } public void run() { while(true) { double a=0,b=0,c=0,root1=0,root2=0; try{ a=in.readDouble(); //堵塞状态，除非读取到信息。 b=in.readDouble(); c=in.readDouble(); double disk=b*b-4*a*c; root1=(-b+Math.sqrt(disk))/(2*a); root2=(-b-Math.sqrt(disk))/(2*a); out.writeDouble(root1); out.writeDouble(root2); } catch (IOException e) { System.out.println("客户离开"); break; } } } }