我正在使用JDBC创建一个Web应用程序。我已将连接器.jar文件添加到Tomcat / lib文件夹中。我在META-INF和web.xml中配置了context.xml。但是，当我运行我的应用程序时，我收到此错误。我无法弄清楚它的原因。也许，一些连接问题。如果你帮助了我，我将非常感激。
的Servlet
@WebServlet("/QueryServlet")
public class QueryServlet extends HttpServlet {
private static final long serialVersionUID = 1L;
DataSource ds;
/**
* @see HttpServlet#HttpServlet()
*/
public QueryServlet() {
super();
// TODO Auto-generated constructor stub
}
/**
* @see HttpServlet#doGet(HttpServletRequest request, HttpServletResponse response)
*/
protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
// Set the MIME type for the response message
response.setContentType("text/html");
// Get a output writer to write the response message into the network socket
PrintWriter out = response.getWriter();
Connection conn = null;
Statement stmt = null;
String url = "jdbc:mysql://localhost:3306/mysql/ebookshop";
String user = "***";
String pwd = "***";
try {
// Step 1: Create a database "Connection" object
// For MySQL
InitialContext ctx = new InitialContext();
ds = (DataSource) ctx.lookup("java:comp/env/jdbc/ebookshop");
//
//DriverManager.registerDriver(new com.mysql.jdbc.Driver());
Class.forName("com.mysql.jdbc.Driver");
conn = ds.getConnection(); // <<== Check
// For MS Access
// conn = DriverManager.getConnection("jdbc:odbc:ebookshopODBC");
// Step 2: Create a "Statement" object inside the "Connection"
stmt = conn.createStatement();
// Step 3: Execute a SQL SELECT query
String sqlStr = "SELECT * FROM books WHERE author = "
+ "'" + request.getParameter("author") + "'"
+ " AND qty > 0 ORDER BY author ASC, title ASC";
// Print an HTML page as output of query
out.println("<html><head><title>Query Results</title></head><body>");
out.println("<h2>Thank you for your query.</h2>");
out.println("<p>You query is: " + sqlStr + "</p>"); // Echo for debugging
ResultSet rset = stmt.executeQuery(sqlStr); // Send the query to the server
// Step 4: Process the query result
int count = 0;
while(rset.next()) {
// Print a paragraph <p>...</p> for each row
out.println("<p>" + rset.getString("author")
+ ", " + rset.getString("title")
+ ", $" + rset.getDouble("price") + "</p>");
++count;
}
out.println("<p>==== " + count + " records found ====</p>");
out.println("</body></html>");
} catch (SQLException | NamingException | ClassNotFoundException ex) {
ex.printStackTrace();
} finally {
out.close();
try {
// Step 5: Close the Statement and Connection
if (stmt != null) stmt.close();
if (conn != null) conn.close();
} catch (SQLException ex) {
ex.printStackTrace();
}
}
}
context.xml中：
<Context antiJARLocking="true" path="/DBConnectionPoolTest">
<Resource name="jdbc/ebookshop"
auth="Container"
type="javax.sql.DataSource"
username="***" password="v"
driverclassname="com.mysql.jdbc.Driver"
url="jdbc:mysql://localhost:3306/ebookshop"
maxactive="10"
maxidle="4" />
</Context>
的pom.xml：
<display-name>ebookshop</display-name>
<resource-ref>
<description>DB Connection Pool</description>
<res-ref-name>jdbc/ebookshop</res-ref-name>
<res-type>javax.sql.DataSource</res-type>
<res-auth>Container</res-auth>
<res-sharing-scope>Shareable</res-sharing-scope>
</resource-ref>
Eclipse输出：
SEVERE: Servlet.service() for servlet [servlets.QueryServlet] in context with path [/ebookshop] threw exception [Servlet execution threw an exception] with root cause
java.lang.AbstractMethodError: com.mysql.jdbc.Connection.isValid(I)Z
at org.apache.tomcat.dbcp.dbcp2.DelegatingConnection.isValid(DelegatingConnection.java:924)
at org.apache.tomcat.dbcp.dbcp2.PoolableConnection.validate(PoolableConnection.java:282)
at org.apache.tomcat.dbcp.dbcp2.PoolableConnectionFactory.validateConnection(PoolableConnectionFactory.java:359)
at org.apache.tomcat.dbcp.dbcp2.BasicDataSource.validateConnectionFactory(BasicDataSource.java:2316)
at org.apache.tomcat.dbcp.dbcp2.BasicDataSource.createPoolableConnectionFactory(BasicDataSource.java:2299)
at org.apache.tomcat.dbcp.dbcp2.BasicDataSource.createDataSource(BasicDataSource.java:2043)
at org.apache.tomcat.dbcp.dbcp2.BasicDataSource.getConnection(BasicDataSource.java:1543)
at servlets.QueryServlet.doGet(QueryServlet.java:61)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:635)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:742)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:231)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166)
at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166)
at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:198)
at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:96)
at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:478)
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:140)
at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:80)
at org.apache.catalina.valves.AbstractAccessLogValve.invoke(AbstractAccessLogValve.java:624)
at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:87)
at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:342)
at org.apache.coyote.http11.Http11Processor.service(Http11Processor.java:799)
at org.apache.coyote.AbstractProcessorLight.process(AbstractProcessorLight.java:66)
at org.apache.coyote.AbstractProtocol$ConnectionHandler.process(AbstractProtocol.java:861)
at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:1455)
at org.apache.tomcat.util.net.SocketProcessorBase.run(SocketProcessorBase.java:49)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)
at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61)
at java.lang.Thread.run(Thread.java:745)