import javax.swing.*;import java.awt.Dimension;
import java.awt.Font;
import java.awt.Toolkit;
import java.awt.event.*;
public class PortScan extends JFrame {JPanel center=new JPanel();Box hBox0=Box.createHorizontalBox();Box hBox1= Box.createHorizontalBox();Box hBox2= Box.createHorizontalBox();Box hBox3= Box.createHorizontalBox();private JLabel state=new JLabel("关闭");private JLabel HOST=new JLabel("主机名:");private JLabel PORT=new JLabel("端口号:");private JLabel STATE=new JLabel("状态：");private JButton btn1=new JButton("开始扫描");private JButton reset=new JButton("重置");private JTextField host=new JTextField(20);private JTextField port=new JTextField(7);Font f1=new Font("隶书",Font.PLAIN,15);public static void main(String[] args) {JFrame portscan=new PortScan();portscan.setVisible(true);}public PortScan(){setTitle("PortScanner");setSize(300, 200);center.setLayout(new BoxLayout(center,BoxLayout.Y_AXIS));Toolkit kit = Toolkit.getDefaultToolkit();Dimension screenSize = kit.getScreenSize();//获取屏幕分辨率setLocation(screenSize.width/4,screenSize.height/4);//位置state.setFont(f1);HOST.setFont(f1);PORT.setFont(f1);btn1.setFont(f1);reset.setFont(f1);STATE.setFont(f1);center.add(hBox0);center.add(Box.createRigidArea(new Dimension(10,20)));center.add(hBox1);center.add(Box.createRigidArea(new Dimension(2,20)));center.add(hBox2);center.add(Box.createRigidArea(new Dimension(2,20)));center.add(hBox3);hBox0.add(HOST);hBox0.add(host);hBox1.add(PORT);hBox1.add(port);hBox2.add(btn1);hBox2.add(reset);hBox3.add(STATE);hBox3.add(state);add(center);btn1.addActionListener(new MyActionListener());reset.addActionListener(new MyActionListener());}class MyActionListener implements ActionListener{@Overridepublic void actionPerformed(ActionEvent e) {String post1=host.getText();int port1=Integer.parseInt(port.getText());if(e.getActionCommand()=="开始扫描"){if(    PortScannerByIP.scan(post1, port1)){state.setText("开放");}else{state.setText("关闭");}}if(e.getActionCommand()=="重置"){host.setText("");port.setText("");}}}
}import java.io.IOException;
import java.net.Socket;public class PortScannerByIP {public static boolean scan(String host,int port){boolean flag=true;Socket socket=null;try {socket=new Socket(host,port);return flag;} catch (IOException e) {flag=false;return flag;}finally{try {if(socket!=null)socket.close();} catch (IOException e) {e.printStackTrace();}}}
}