Pool doesn't in servlet but works in standalone appication.
Pool class is common in two cases:
public class Pool {
private static DataSource ds;
static {
DriverAdapterCPDS cpds = new DriverAdapterCPDS();
try {
cpds.setDriver("com.mysql.jdbc.Driver");
} catch (ClassNotFoundException e) {
e.printStackTrace();
}
cpds.setUrl("jdbc:mysql://localhost:3306/collage");
cpds.setUser("root");
cpds.setPassword("r00t");
SharedPoolDataSource tds = new SharedPoolDataSource();
tds.setConnectionPoolDataSource(cpds);
tds.setMaxTotal(10);
/*tds.setMaxWait(50);
tds.setMaxTotal();*/
tds.setMaxTotal(50);
ds = tds;
}
public static Connection getConnection() throws SQLException {
return ds.getConnection();
}
for standalone class it works as following
public class MainClass {
public static void main(String[] args) {
Connection connection = null;
Statement statement = null;
ResultSet resultSet = null;
try {
connection = Pool.getConnection();
// Do work with connection
statement = connection.createStatement();
String selectEmployeesSQL = "select * from students";
resultSet = statement.executeQuery(selectEmployeesSQL);
while (resultSet.next()) {
printTestTable(resultSet);
}
} catch (Exception e) {
e.printStackTrace();
} finnaly {
...
}
}
And from part from servlet is following:
@WebServlet("/Demo.do")
public class DemoController extends HttpServlet {
protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
ResultSet rsObj = null;
Connection connObj = null;
PreparedStatement pstmtObj = null;
try {
connObj = Pool.getConnection();
...
And exception is here"
HTTP Status 500 – Internal Server Error
Type Exception Report
Message Servlet execution threw an exception
Description The server encountered an unexpected condition that prevented it from fulfilling the request.
Exception
javax.servlet.ServletException: Servlet execution threw an exception
org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:53)
Root Cause
java.lang.NoClassDefFoundError: Could not initialize class am.ak.dao.jdbc.connections.Pool
test.DemoController.doGet(DemoController.java:27)
javax.servlet.http.HttpServlet.service(HttpServlet.java:634)
javax.servlet.http.HttpServlet.service(HttpServlet.java:741)
org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:53)
Note The full stack trace of the root cause is available in the server logs.
Thanks.
ADDED:
Artifacts in Project settings:
RESOLVED:
So this two lib were missed )
Interesting: In POM I added only one dependency bot it shoes two :
<dependency>
<groupId>org.apache.commons</groupId>
<artifactId>commons-dbcp2</artifactId>
<version>2.5.0</version>
</dependency>