在jar文件中包裝嵌入式數據庫

Question

我在eclipse項目中創建了一個derby嵌入式數據庫，並且它在eclipse上運行良好，但是在Runnable jar文件中打包項目時，它在連接數據庫時失敗。

我做過類似這樣的視頻 http://vinayakgarg.wordpress.com/2012/03/07/packaging-java-application-with-apache-derby-as-jar-executable-using-eclipse/

這東西是我的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 + "\'");  
} 
} 

在這個問題上的任何幫助嗎？

Answer 1

數據庫應該位於運行jar的文件夾中。如果不是，請檢查文檔如何指定connectionURL。如果項目導出到可運行jar文件，則指定依賴庫不會被提取，而只是添加到jar或本地lib文件夾中。這些庫是derby.jar和derbytools.jar應位於類路徑或清單類路徑中。使用以下代碼來測試您的

Communicate類。

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"); 
    } 


} 

這是輸出：

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