Datenbank Verbindung

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    • Datenbank Verbindung

      Java-Quellcode: DatabaseConnection

      1. import java.sql.Connection;
      2. import java.sql.DriverManager;
      3. import java.sql.PreparedStatement;
      4. import java.sql.ResultSet;
      5. import java.sql.SQLException;
      7. /**
      8. * Database Class with Connect, Disconnect and Resultset.
      9. *
      10. * @author Tim Lorse
      11. * @version Version 1.0
      12. */
      13. public class Database {
      15. /**
      16. * Connection for Database HyperSQL(HSQLDB) on Localhost with Login SA.
      17. *
      18. * @return Connection if Successful
      19. */
      20. public Connection connect() {
      21. return connect("SA", "");
      22. }
      24. /**
      25. * Connection for Database MySQL on Localhost with Login root.
      26. *
      27. * @return Connection if Successful
      28. */
      29. public Connection connect_mysql(){
      30. return connect_mysql("root", "");
      31. }
      33. /**
      34. * Connection for Database HyperSQL(HSQLDB) on Localhost without Login User.
      35. *
      36. * @param usr Username to Connect with the Database.
      37. * @param passwd Password to Authentication the User.
      38. * @return Connection if Successful
      39. */
      40. public Connection connect(String usr, String passwd) {
      41. return connect("jdbc:hsqldb:hsql://localhost/", usr, passwd);
      42. }
      44. /**
      45. * Connection for Database MySQL on Localhost without Login User.
      46. *
      47. * @param usr Username to Connect with the Database.
      48. * @param passwd Password to Authentication the User.
      49. * @return Connection if Successful
      50. */
      51. public Connection connect_mysql(String usr, String passwd){
      52. return connect_mysql("jdbc:mysql://localhost:3306", usr, passwd);
      53. }
      55. /**
      56. * Connection for Database HyperSQL(HSQLDB) without Login User, Password and
      57. * URL
      58. *
      59. * @param url URL to the Database for Example<br>
      60. * <strong>HSQLDB: </strong>"jdbc:hsqldb:hsql://localhost/"
      61. * @param usr Username to Connect with the Database.
      62. * @param passwd Password to Authentication the User.
      63. * @return Connection if Successful
      64. */
      65. public Connection connect(String url, String usr, String passwd) {
      66. return connect(url, usr, passwd, "org.hsqldb.jdbcDriver");
      67. }
      69. /**
      70. * Connection for Database MySQL without Login User, Password and
      71. * URL
      72. *
      73. * @param url URL to the Database for Example<br>
      74. * <strong>MySQL: </strong>"jdbc:mysql://localhost:3306"
      75. * @param usr Username to Connect with the Database.
      76. * @param passwd Password to Authentication the User.
      77. * @return Connection if Successful
      78. */
      79. public Connection connect_mysql(String url, String usr, String passwd){
      80. return connect(url, usr, passwd, "com.mysql.jdbc.Driver");
      81. }
      83. /**
      84. * Connection without any User, Password or Driver.
      85. *
      86. * @param url URL to the Database for Example <br>
      87. * <strong>HSQLDB: </strong>"jdbc:hsqldb:hsql://localhost/"<br>
      88. * <strong>MySQL: </strong>"jdbc:mysql://localhost:3306"
      89. * @param usr Username to Connect with the Database.
      90. * @param passwd Password to Authentication the User.
      91. * @param driver Database driver. For Example<br>
      92. * <strong>HSQLDB: </strong>"org.hsqldb.jdbcDriver"<br>
      93. * <strong>MySQL: </strong>"com.mysql.jdbc.Driver"
      94. * @return Connection if Successful
      95. */
      96. public Connection connect(String url, String usr, String passwd, String driver) {
      97. Connection con = null;
      98. try {
      99. // Treiber Laden
      100. Class.forName(driver);
      102. con = DriverManager.getConnection(url, usr, passwd);
      103. } catch (ClassNotFoundException cnfe) {
      104. System.err.println("connect: Database Driver not found: " + cnfe);
      105. } catch (SQLException ex) {
      106. System.err.println("connect: " + ex);
      107. }
      108. return con;
      109. }
      111. /**
      112. * Disconnect the Database
      113. * @param con Connection
      114. * @return True or False
      115. */
      116. public boolean disconnect(Connection con) {
      117. boolean ret = false;
      118. if (con != null) {
      119. try {
      120. if (!con.isClosed()) {
      121. con.close();
      122. ret = true;
      123. }
      124. } catch (SQLException ex) {
      125. System.err.println("Exception in disconnect: " + ex);
      126. }
      127. }
      128. return ret;
      129. }
      131. /**
      132. * Resultset from a complete Table
      133. *
      134. * @param con Connection
      135. * @param table Tablename
      136. * @param attribut Attributname
      137. * @param value Value
      138. * @return Result
      139. */
      140. public static ResultSet getResut(Connection con, String table, String attribut, String value) {
      141. ResultSet rs = null;
      142. try (PreparedStatement ptsm = con.prepareStatement("SELECT * FROM " + table + " WHERE " + attribut + " LIKE " + value)) {
      143. rs = ptsm.executeQuery();
      144. } catch (SQLException ex) {
      145. System.err.println("getResult: " + ex);
      146. }
      147. return rs;
      148. }
      149. }
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