Packing embedded database in jar file

问题

I've created a derby Embedded Database in my eclipse project, and it runs well on eclipse, but when packing the project in Runnable jar file, it fails in connecting the database.

I've done something similar to this video http://vinayakgarg.wordpress.com/2012/03/07/packaging-java-application-with-apache-derby-as-jar-executable-using-eclipse/

Here is my Communicate.java

import java.io.File;
import java.security.NoSuchAlgorithmException;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;

public class Communicate {

private static final String dbURL = "jdbc:derby:imagesDB;create=true";
private static final String tableName = "imageDB";
private static Connection conn = null;
private static Statement stmt = null;

public void insert(String path, String hash, long FileSize,
        String label_name) throws NoSuchAlgorithmException, Exception {
    try {
        stmt = conn.createStatement();
        stmt.execute("insert into " + tableName + " values (\'" + path
                + "\'," + FileSize + ",\'" + hash + "\'" + ",\'"
                + label_name + "\')");
        stmt.close();
    } catch (SQLException sqlExcept) {
        sqlExcept.printStackTrace();
    }
}

public void createConnection() {
    try {
        Class.forName("org.apache.derby.jdbc.EmbeddedDriver").newInstance();
        // Get a connection
        conn = DriverManager.getConnection(dbURL);
    } catch (Exception except) {
        except.printStackTrace();
    }
}

public void createTable() throws SQLException {
    Statement st = conn.createStatement();
    st.execute("CREATE TABLE "
            + tableName
            + " (fullPath VARCHAR(512), fileSize INTEGER, md5 VARCHAR(512), label_name VARCHAR(100))");
}

public void indexTable() throws SQLException {
    Statement st = conn.createStatement();
    st.execute("CREATE INDEX imageDBIndex ON imageDB (fullPath, label_name)");
}

public void deleteTable() throws SQLException {
    Statement st = conn.createStatement();
    st.execute("drop table " + tableName);
}

public String searchBySizeAndMD(String file_path, long size, String hash)
        throws SQLException {
    StringBuilder sb = new StringBuilder();
    Statement st = conn.createStatement();
    ResultSet rs = st
            .executeQuery("SELECT fullPath, label_name FROM (SELECT * FROM imageDB im WHERE im.fileSize = "
                    + size + " ) as A WHERE A.md5 = " + "\'" + hash + "\'");
    while (rs.next()) {
        sb.append("Image: (" + rs.getString("fullPath")
                + ") is at label: (" + rs.getString("label_name") + ")\n");
    }
    return sb.toString();
}

public String searchByImageName(String fileName) throws SQLException {
    StringBuilder sb = new StringBuilder();
    Statement st = conn.createStatement();
    ResultSet rs = st
            .executeQuery("SELECT fullPath, label_name FROM imageDB im WHERE im.fullPath like \'%"
                    + fileName + "%\'");
    while (rs.next()) {
        File out_path = new File(rs.getString("fullPath"));
        if (!fileName.equals(out_path.getName())) continue;
        sb.append("Image: (" + out_path.getPath()
                + ") is at label: (" + rs.getString("label_name") + ")\n");
    }

    return sb.toString();
}

public void deleteLabel(String label) throws SQLException {
    Statement st = conn.createStatement();
    st.execute("DELETE FROM " + tableName + " WHERE label_name = \'" + label + "\'");       
}
 }

Any help in this issue?

回答1:

The database should be in the folder where you runs the jar. If it's not then check docs how to specify connectionURL. If the project exported to the runnable jar file specify dependent libraries not to be extracted just added as is to the jar or to the local lib folder. These libraries are derby.jar and derbytools.jar should be in the classpath or manifest classpath. Use the following code to test your

Communicate class.

import java.io.File;
import java.security.NoSuchAlgorithmException;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;

public class Communicate {

  private static final String dbURL = "jdbc:derby:imagesDB;create=true";
  private static final String tableName = "imageDB";
  private static Connection conn = null;
  private static Statement stmt = null;

  public void insert(String path, String hash, long FileSize,
                     String label_name) throws NoSuchAlgorithmException, Exception {
    try {
      stmt = conn.createStatement();
      stmt.execute("insert into " + tableName + " values (\'" + path
        + "\'," + FileSize + ",\'" + hash + "\'" + ",\'"
        + label_name + "\')");
      stmt.close();
      System.out.println("Inserted into table "+ tableName+ " values (\'" + path
        + "\'," + FileSize + ",\'" + hash + "\'" + ",\'"
        + label_name + "\')");
    } catch (SQLException sqlExcept) {
      sqlExcept.printStackTrace();
    }
  }

  public void loadDriver() {
    try {
      Class.forName("org.apache.derby.jdbc.EmbeddedDriver").newInstance();
      System.out.println("Loaded the appropriate driver");
    } catch (Exception except) {
      except.printStackTrace();
    }
  }

  public void createConnection() {
    try {
      // Get a connection
      conn = DriverManager.getConnection(dbURL);
      System.out.println("Connected to and created database ");
    } catch (Exception except) {
      except.printStackTrace();
    }
  }

  public void createTable() throws SQLException {
    Statement st = conn.createStatement();
    st.execute("CREATE TABLE "
      + tableName
      + " (fullPath VARCHAR(512), fileSize INTEGER, md5 VARCHAR(512), label_name VARCHAR(100))");
    System.out.println("Created table "+ tableName);
  }

  public void indexTable() throws SQLException {
    Statement st = conn.createStatement();
    st.execute("CREATE INDEX imageDBIndex ON imageDB (fullPath, label_name)");
    System.out.println("Created index "+ "imageDBIndex");
  }

  public void deleteTable() throws SQLException {
    Statement st = conn.createStatement();
    st.execute("drop table " + tableName);
    System.out.println("Deleted table "+ tableName);
  }

  public String searchBySizeAndMD(String file_path, long size, String hash)
    throws SQLException {
    StringBuilder sb = new StringBuilder();
    Statement st = conn.createStatement();
    ResultSet rs = st
      .executeQuery("SELECT fullPath, label_name FROM (SELECT * FROM imageDB im WHERE im.fileSize = "
        + size + " ) as A WHERE A.md5 = " + "\'" + hash + "\'");
    while (rs.next()) {
      sb.append("Image: (" + rs.getString("fullPath")
        + ") is at label: (" + rs.getString("label_name") + ")\n");
    }
    return sb.toString();
  }

  public String searchByImageName(String fileName) throws SQLException {
    StringBuilder sb = new StringBuilder();
    Statement st = conn.createStatement();
    ResultSet rs = st
      .executeQuery("SELECT fullPath, label_name FROM imageDB im WHERE im.fullPath like \'%"
        + fileName + "%\'");
    while (rs.next()) {
      File out_path = new File(rs.getString("fullPath"));
      if (!fileName.equals(out_path.getName())) continue;
      sb.append("Image: (" + out_path.getPath()
        + ") is at label: (" + rs.getString("label_name") + ")\n");
    }

    return sb.toString();
  }

  public void deleteLabel(String label) throws SQLException {
    Statement st = conn.createStatement();
    st.execute("DELETE FROM " + tableName + " WHERE label_name = \'" + label + "\'");
  }

  public static void main(String[] args)
  {
    Communicate c = new Communicate();
    c.loadDriver();
    try {
      c.createConnection();
      c.createTable();
      c.indexTable();
      c.insert("/some/path", "12323423", 45656567, "label name");
      String s = c.searchBySizeAndMD("/some/path", 45656567, "12323423");
      System.out.println("Search result: "+ s);
      c.deleteTable();
      conn.commit();
      System.out.println("Committed the transaction");

      //Shutdown embedded database
      try
      {
        // the shutdown=true attribute shuts down Derby
        DriverManager.getConnection("jdbc:derby:;shutdown=true");

      }
      catch (SQLException se)
      {
        if (( (se.getErrorCode() == 50000)
          && ("XJ015".equals(se.getSQLState()) ))) {
          // we got the expected exception
          System.out.println("Derby shut down normally");
        } else {
          System.err.println("Derby did not shut down normally");
          System.err.println("  Message:    " + se.getMessage());
        }
      }

    } catch (Exception e) {
      System.err.println("  Message:    " + e.getMessage());
    } finally {
      // release all open resources to avoid unnecessary memory usage

      //Connection
      try {
        if (conn != null) {
          conn.close();
          conn = null;
        }
      } catch (SQLException e) {
        System.err.println("  Message:    " + e.getMessage());
      }
    }
    System.out.println("Communicate finished");
  }


}

This is the output:

Loaded the appropriate driver
Connected to and created database 
Created table imageDB
Created index imageDBIndex
Inserted into table imageDB values ('/some/path',45656567,'12323423','label name')
Search result: Image: (/some/path) is at label: (label name)

Deleted table imageDB
Committed the transaction
Derby shut down normally
Communicate finished

来源：https://stackoverflow.com/questions/11864443/packing-embedded-database-in-jar-file

标签

java

database

jdbc

derby