五月二十八号

public class app17_22 {
    private static String driver = "com.mysql.jdbc.Driver";
    private static String url = "jdbc:mysql://localhost:3306/k";
    private static String user = "root";
    private static String password = "root";
    public static void main(String[] args) {
        Connection conn = null;
        Statement stmt = null;
        ResultSet rs = null;
        String insertSql1 = "INSERT INTO student(sNo,sName,sex,age,dept) VALUES(‘4‘,‘zs‘,‘nan‘,21,‘计算机‘)";
        String insertSql2 = "INSERT INTO student(sNo,sName,sex,age,dept) VALUES(‘5‘,‘ls‘,‘nv‘,22,‘外语‘)";
        String insertSql3 = "INSERT INTO student(sNo,sName,sex,age,dept) VALUES(‘6‘,‘ww‘,‘nan‘,‘23‘,‘计算机‘)";
        boolean ynRollback = true;
        try{
            Class.forName(driver);
            conn = DriverManager.getConnection(url,user,password);
            stmt = conn.createStatement();
            boolean autoCommit = conn.getAutoCommit();//返回是否为自动提交模式
            conn.setAutoCommit(false);//取消自动提交
            stmt.executeUpdate(insertSql1);
            Savepoint s1 = conn.setSavepoint();//回滚到提交点
            stmt.executeUpdate(insertSql2);
            stmt.executeUpdate(insertSql3);
            conn.commit();//自动提交
            conn.setAutoCommit(autoCommit);
        }
        catch(Exception e){
            e.printStackTrace();
            if (conn!=null){
                try{
                    conn.rollback();
                }
                catch (SQLException e1){
                    e1.printStackTrace();
                }
            }
        }
        finally {
            try{
                if (stmt!=null) stmt.close();
                if (conn!=null) conn.close();
            }
            catch (Exception el){
                el.printStackTrace();
            }
        }
    }
}

public class app18_1 {
    public static void main(String[] args) {
        String urlName = "http://www.edu.cn/index.html";
        if (args.length>0) urlName = args[0];
        new app18_1().display(urlName);
    }
    public void display(String urlName){
        try{
            URL url = new URL(urlName);
            InputStreamReader in = new InputStreamReader(url.openStream());//打开输入流作参数，创建读入流对象
            BufferedReader br =new BufferedReader(in);
            String aLine;
            while((aLine = br.readLine())!=null){
                System.out.println(aLine);
            }
        }
        catch(MalformedURLException murle){
            System.out.println(murle);
        }
        catch (Exception e){
            System.out.println(e);
        }

    }
}

public class app18_2 {
    InetAddress myIPAddress =null;
    InetAddress myServer = null;

    public static void main(String[] args) {
        app18_2 search = new app18_2();
        System.out.println("主机号IP为："+search.myIP());
        System.out.println("服务器号IP为："+search.myServer);
    }
    public InetAddress myIP(){
        try{ myIPAddress = InetAddress.getLocalHost();}//获取主机名
        catch (UnknownHostException e){ }
        return (myIPAddress);
    }
    public InetAddress myServer(){
        try{
            myServer = InetAddress.getByName("www.tom.com");
        }
        catch (UnknownHostException e){
        }
        return(myServer);
    }
}