在jar文件中打包嵌入式数据库

我在我的eclipse项目中创建了一个derby嵌入式数据库，它在eclipse上运行良好，但是当在Runnable jar文件中打包项目时，它在连接数据库时失败了。

我做了类似于这个video的事情http://vinayakgarg.wordpress.com/2012/03/07/packaging-java-application-with-apache-derby-as-jar-executable-using-eclipse/

这是我的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 + "\'"); } } 

这个问题有什么帮助吗？

Answer 1

数据库应位于运行jar的文件夹中。 如果不是，则检查docs如何指定connectionURL 。 如果导出到runnable jar文件的项目指定不提取的依赖库，则只是将其添加到jar或本地lib文件夹中。 这些库是derby.jar ， derbytools.jar应该在classpath或manifest类路径中。 使用以下代码测试您的

Communicate课。

 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"); } } 

这是输出：

 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