如何解决这个 java.lang.ClassCastException: org.apache.tomcat.dbcp.dbcp.BasicDataSource cannot be cast to org.apache.tomcat.jdbc.pool.D
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how to solve this java.lang.ClassCastException: org.apache.tomcat.dbcp.dbcp.BasicDataSource cannot be cast to org.apache.tomcat.jdbc.pool.DataSource?
提问by CodeNotFound
I am trying to do the database connection in tomcat using pooling, this is the what is my context :
我正在尝试使用池在 tomcat 中进行数据库连接，这就是我的上下文：
<Resource name="jdbc/slingemp" auth="Container" type="javax.sql.DataSource"
maxActive="100" maxIdle="30" maxWait="10000"
username="root" password="root" driverClassName="com.mysql.jdbc.Driver"
url="jdbc:mysql://localhost:3306/slingemp"/>
and this is what is my web.xml :
这就是我的 web.xml ：
<description>MySQL JNDI Test</description>
<resource-ref>
<description>DB Connection</description>
<res-ref-name>jdbc/slingemp</res-ref-name>
<res-type>javax.sql.DataSource</res-type>
<res-auth>Container</res-auth>
</resource-ref>
and this is how i connect with database :
这就是我与数据库连接的方式：
package org.slingemp.jnditest;
import java.io.IOException;
import java.sql.Connection;
import javax.naming.Context;
import javax.naming.InitialContext;
import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import org.apache.tomcat.jdbc.pool.DataSource;
/**
* Servlet implementation class JNDILookUpServlet
*/
@WebServlet("/JNDILookUpServlet")
public class JNDILookUpServlet extends HttpServlet {
private static final long serialVersionUID = 1L;
/**
* @see HttpServlet#HttpServlet()
*/
public JNDILookUpServlet() {
super();
// TODO Auto-generated constructor stub
}
/**
* @see HttpServlet#doGet(HttpServletRequest request, HttpServletResponse response)
*/
protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
// TODO Auto-generated method stub
}
/**
* @see HttpServlet#doPost(HttpServletRequest request, HttpServletResponse response)
*/
protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
// TODO Auto-generated method stub
try {
Context initContext = new InitialContext();
Context envContext = (Context)initContext.lookup("java:/comp/env");
DataSource ds = (DataSource)envContext.lookup("jdbc/slingemp");
Connection conn = ds.getConnection();
if(conn != null)System.out.println("Connected..");
else System.out.println("Not connected...");
} catch (Exception e) {
e.printStackTrace();
}
response.sendRedirect("index.jsp");
}
}
but it gives me the following exception :
但它给了我以下例外：
java.lang.ClassCastException: org.apache.tomcat.dbcp.dbcp.BasicDataSource cannot be cast to org.apache.tomcat.jdbc.pool.DataSource
Please help me to resolve this,
请帮我解决这个问题，
Regards
问候
回答by Sean Patrick Floyd
You are just using the wrong import.
您只是使用了错误的导入。
replace this:
替换这个：
import org.apache.tomcat.jdbc.pool.DataSource;
with this:
有了这个：
import javax.sql.DataSource;
javax.sql.DataSourceis the base interface that all DataSourceimplementations must inherit. It is usually not advisable to develop against anything else than this interface.
javax.sql.DataSource是所有DataSource实现都必须继承的基本接口。通常不建议针对此接口以外的任何其他内容进行开发。
