Verify database setup : Connection « Database SQL JDBC « Java

1. Java
2. Database SQL JDBC
3. Connection

Verify database setup

    
import java.sql.*;

public class CheckJDBCInstallation {
  /**
   * Test Validity of JDBC Installation
   * 
   * @param conn
   *          a JDBC connection object
   * @param dbVendor
   *          db vendor {"oracle", "mysql" }
   * @return true if a given connection object is a valid one; otherwise return
   *         false.
   * @throws Exception
   *           Failed to determine if a given connection is valid.
   */
  public static boolean isValidConnection(Connection conn, String dbVendor) throws Exception {
    if (conn == null) {
      return false;
    }

    if (conn.isClosed()) {
      return false;
    }
    // depends on the vendor of the database:
    //
    // for MySQL database:
    // you may use the connection object
    // with query of "select 1"; if the
    // query returns the result, then it
    // is a valid Connection object.
    //
    // for Oracle database:
    // you may use the Connection object
    // with query of "select 1 from dual"; if
    // the query returns the result, then it
    // is a valid Connection object.
    if (dbVendor.equalsIgnoreCase("mysql")) {
      return testConnection(conn, "select 1");
    } else if (dbVendor.equalsIgnoreCase("oracle")) {
      return testConnection(conn, "select 1 from dual");
    } else {
      return false;
    }

  }

  /**
   * Test Validity of a Connection
   * 
   * @param conn
   *          a JDBC connection object
   * @param query
   *          a sql query to test against db connection
   * @return true if a given connection object is a valid one; otherwise return
   *         false.
   */
  public static boolean testConnection(Connection conn, String query) {
    ResultSet rs = null;
    Statement stmt = null;
    try {
      stmt = conn.createStatement();
      if (stmt == null) {
        return false;
      }

      rs = stmt.executeQuery(query);
      if (rs == null) {
        return false;
      }

      // connection object is valid: you were able to
      // connect to the database and return something useful.
      if (rs.next()) {
        return true;
      }

      // there is no hope any more for the validity
      // of the Connection object
      return false;
    } catch (Exception e) {
      // something went wrong: connection is bad
      return false;
    } finally {
      // close database resources
      try {
        rs.close();
        stmt.close();        
      } catch (SQLException e) {
        e.printStackTrace();
      }
    }
  }

  public static void main(String[] args) {
    Connection conn = null;
    try {
      String dbVendor = args[0];
      // get connection to a database
      System.out.println("dbVendor=" + dbVendor);
      System.out.println("conn=" + conn);
      System.out.println("valid connection = " + isValidConnection(conn, dbVendor));
    } catch (Exception e) {
      // handle the exception
      e.printStackTrace();
      System.exit(1);
    } finally {
      // release database resources
      try {
        conn.close();
      } catch (SQLException e) {
        e.printStackTrace();
      }
    }
  }
}

           
         
    
    
    
  

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