連接認證失敗JDBC

Question

在主項目類中調用此方法時，填寫參數等，我收到一個錯誤。表中的字段列爲ID，我正在從用戶字段接收用戶輸入，並將其與SQL表中的ID字段進行比較。如果來自用戶的輸入與SQL表中的ID字段和PASSWORD字段相匹配，則應將用戶發送到主GUI屏幕。然而，這種情況並非如此。

錯誤：

run: java.sql.SQLSyntaxErrorException: Comparisons between 'INTEGER' and 'CHAR (UCS_BASIC)' are not supported. Types must be comparable. String types must also have matching collation. If collation does not match, a possible solution is to cast operands to force them to the default collation (e.g. SELECT tablename FROM sys.systables WHERE CAST(tablename AS VARCHAR(128)) = 'T1') at org.apache.derby.client.am.SQLExceptionFactory40.getSQLException(Unknown Source) at org.apache.derby.client.am.SqlException.getSQLException(Unknown Source) at org.apache.derby.client.am.Statement.executeQuery(Unknown Source) at GUI.Login_Check.CoLogin(Login_Check.java:27) at GUI.Login.btnSubmitActionPerformed(Login.java:208) at GUI.Login.access$200(Login.java:17) at GUI.Login$3.actionPerformed(Login.java:110) at javax.swing.AbstractButton.fireActionPerformed(AbstractButton.java:2022) at javax.swing.AbstractButton$Handler.actionPerformed(AbstractButton.java:2346) at javax.swing.DefaultButtonModel.fireActionPerformed(DefaultButtonModel.java:402) at javax.swing.DefaultButtonModel.setPressed(DefaultButtonModel.java:259) at javax.swing.plaf.basic.BasicButtonListener.mouseReleased(BasicButtonListener.java:252) at java.awt.Component.processMouseEvent(Component.java:6525) at javax.swing.JComponent.processMouseEvent(JComponent.java:3324) at java.awt.Component.processEvent(Component.java:6290) at java.awt.Container.processEvent(Container.java:2234) at java.awt.Component.dispatchEventImpl(Component.java:4881) at java.awt.Container.dispatchEventImpl(Container.java:2292) at java.awt.Component.dispatchEvent(Component.java:4703) at java.awt.LightweightDispatcher.retargetMouseEvent(Container.java:4898) at java.awt.LightweightDispatcher.processMouseEvent(Container.java:4533) at java.awt.LightweightDispatcher.dispatchEvent(Container.java:4462) at java.awt.Container.dispatchEventImpl(Container.java:2278) at java.awt.Window.dispatchEventImpl(Window.java:2750) at java.awt.Component.dispatchEvent(Component.java:4703) at java.awt.EventQueue.dispatchEventImpl(EventQueue.java:758) at java.awt.EventQueue.access$500(EventQueue.java:97) at java.awt.EventQueue$3.run(EventQueue.java:709) at java.awt.EventQueue$3.run(EventQueue.java:703) at java.security.AccessController.doPrivileged(Native Method) at java.security.ProtectionDomain$1.doIntersectionPrivilege(ProtectionDomain.java:75) at java.security.ProtectionDomain$1.doIntersectionPrivilege(ProtectionDomain.java:86) at java.awt.EventQueue$4.run(EventQueue.java:731) at java.awt.EventQueue$4.run(EventQueue.java:729) at java.security.AccessController.doPrivileged(Native Method) at java.security.ProtectionDomain$1.doIntersectionPrivilege(ProtectionDomain.java:75) at java.awt.EventQueue.dispatchEvent(EventQueue.java:728) at java.awt.EventDispatchThread.pumpOneEventForFilters(EventDispatchThread.java:201) at java.awt.EventDispatchThread.pumpEventsForFilter(EventDispatchThread.java:116) at java.awt.EventDispatchThread.pumpEventsForHierarchy(EventDispatchThread.java:105) at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:101) at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:93) at java.awt.EventDispatchThread.run(EventDispatchThread.java:82) Caused by: org.apache.derby.client.am.SqlException: Comparisons between 'INTEGER' and 'CHAR (UCS_BASIC)' are not supported. Types must be comparable. String types must also have matching collation. If collation does not match, a possible solution is to cast operands to force them to the default collation (e.g. SELECT tablename FROM sys.systables WHERE CAST(tablename AS VARCHAR(128)) = 'T1') at org.apache.derby.client.am.Statement.completeSqlca(Unknown Source) at org.apache.derby.client.net.NetStatementReply.parsePrepareError(Unknown Source) at org.apache.derby.client.net.NetStatementReply.parsePRPSQLSTTreply(Unknown Source) at org.apache.derby.client.net.NetStatementReply.readPrepareDescribeOutput(Unknown Source) at org.apache.derby.client.net.StatementReply.readPrepareDescribeOutput(Unknown Source) at org.apache.derby.client.net.NetStatement.readPrepareDescribeOutput_(Unknown Source) at org.apache.derby.client.am.Statement.readPrepareDescribeOutput(Unknown Source) at org.apache.derby.client.am.Statement.flowExecute(Unknown Source) at org.apache.derby.client.am.Statement.executeQueryX(Unknown Source) ... 41 more

代碼：

public static void CoLogin(String username, String password){ 
    try{ 
     String dbuser = ""; 
     String dbpass = ""; 
     String url = "jdbc:derby://localhost:1527/Java-App"; 
     String user = username; 
     String pass = password; 
     Connection con = DriverManager.getConnection(url, "admin", "admin"); 

     Statement stmt = con.createStatement(); 
     String SQL = "SELECT * FROM MEMBERS WHERE ID='" + user + "' && PASSWORD='" + pass + "'"; 
     ResultSet rs = stmt.executeQuery(SQL); 

     while(rs.next()){ 
      dbuser= rs.getString("ID"); 
      dbpass = rs.getString("PASSWORD"); 
     } 
     if(user.equals(dbuser) && pass.equals(dbpass)){ 
       Main x = new Main(); 
       x.setVisible(true); 
     } 
     else{ 
      Login x = new Login(); 
      x.setVisible(true); 
     } 

     //Connection con = DriverManager.getConnection(url, user,  pass); 

    } 
    catch(SQLException error){ 
     System.out.println(error.getMessage()); 
    } 

Answer 1

你的問題可能有很多原因。

但是，如果用戶鍵入username =「」，password =「」他將在任何情況下進行身份驗證。還介意SQL injection。

Answer 2

根據你的日誌，你的錯誤的根本原因是在momment您建立與數據庫的連接，在日線：

Connection con = DriverManager.getConnection(url, "admin", "admin"); 

訊息話題Connection authentication failure occurred. Reason: Userid or password invalid.告訴你，「管理員」錯誤用戶或passowrd用於連接到您的德比數據庫是不正確的。

你可以做的是，使用驗證的數據連接到數據庫，檢查他們在像數據源資源管理器在Eclpise或數據庫資源管理器在Netbeans的數據庫客戶端之前。一旦確定數據庫的驗證數據是正確的，請在代碼中使用它。