Java

Sissejuhatus

TODO

Java paigaldamine

TODO

Java kasutamine

Lähtetekst

$ cat HelloWorld.java
public class HelloWorld {
  public static void main(String[] args) {
    System.out.println("Hello, World");
  }
}

Kompileerimine, tekib fail HelloWorld.class

$ javac HelloWorld.java

Käivitamine

$ java HelloWorld
Hello, World

Ühendus Oracle andmebaasiga

Nt Oracle 10.2.0.4 andmebaasiga suhtlemiseks on vajalik draiver ojdbc14.jar

import java.sql.*;
import java.sql.DriverManager;
import java.sql.SQLException;
import java.net.*;

public class HelloOracle
    {
        public static void main(String args[]) throws SQLException {
            Connection con = null;
            try {
                Class.forName("oracle.jdbc.driver.OracleDriver");
                con = DriverManager.getConnection("jdbc:oracle:thin:@192.168.13.64:1521:loom", \
                  "mart", "mardiparool");
                Statement st = con.createStatement();
                ResultSet rs = st.executeQuery("select BANNER from SYS.V_$VERSION");
                while(rs.next()) {
                     System.out.println(rs.getString(1));
                }
            } catch (Exception e) {
                e.printStackTrace();
            } finally {
                if(con != null) {
                    con.close();
                }
            }
        }
    }

kus

• loom - oracle baasi SID

Kompileerimiseks

$ export CLASSPATH=ojdbc14.jar:.
$ javac HelloOracle.java

ja käivitamiseks

$ java HelloOracle

Ühendus PostgreSQL andmebaasiga

$ cat HelloPostgresql.java
import java.sql.*;
import java.sql.DriverManager;
import java.sql.SQLException;
import java.net.*;

public class HelloPostgresql
     {
         public static void main(String args[]) throws SQLException {
             Connection con = null;
             try {
                 Class.forName("org.postgresql.Driver");
                 con = DriverManager.getConnection("jdbc:postgresql://127.0.0.1/test", "priit", "parool");
                 Statement st = con.createStatement();
                 ResultSet rs = st.executeQuery("SELECT * FROM priit.inimene");
                 while(rs.next()) {
                      System.out.println(rs.getString("nimi"));
                 }
             } catch (Exception e) {
                 e.printStackTrace();
             } finally {
                 if(con != null) {
                     con.close();
                 }
             }
         }
     }

Kompileerimiseks

$ export CLASSPATH=postgresql-8.4-701.jdbc3.jar:.
$ javac HelloPostgresql.java

Käivitamiseks

$ java HelloPostgresql

Märkused

• Selleks, et java.sun.com võrk töötaks Debian Squeeze 20100402 seisuga, tuleb öelda, http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=560044

# sysctl -w net.ipv6.bindv6only=0

Kasulikud lisamaterjalid

• http://www.cs.princeton.edu/introcs/home/
• http://www.fankhausers.com/postgresql/jdbc/
• http://en.wikipedia.org/wiki/Jetty_(web_server)