Tomcat连接池提示驱动错误

Question

tomcat中的server.xml
...
type="javax.sql.DataSource"
driverClassName="com.mysql.jdbc.Driver"
url="jdbc:mysql://localhost:3306/webdb?characterEncoding=utf-8"
username="root"
password="sa123456"
maxActive="200"
maxIdle="50"
maxWait="3000"
/>
...

tomcat中的webdemo3.xml

项目里的web.xml
<?xml version="1.0" encoding="UTF-8"?>

webdemo3

index.html
index.htm
index.jsp
default.html
default.htm
default.jsp


viewDictory
webdemo3.chapter04.ViewDictionary


viewDictory
/servlet/ViewDictionary


DB Connection
jdbc/webdb2
javax.sql.DataSource
Container

项目中的ViewDictionary.java
package webdemo3.chapter04;

import java.io.IOException;
import java.io.PrintWriter;
import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.ResultSet;

import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

/**

• Servlet implementation class ViewDictionary
  */
  public class ViewDictionary extends HttpServlet {
  private static final long serialVersionUID = 1L;

  /**

  • @see HttpServlet#HttpServlet() */ public ViewDictionary() { super(); // TODO Auto-generated constructor stub }

  /**

  • @see HttpServlet#doGet(HttpServletRequest request, HttpServletResponse response)
    */
    protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
    response.setContentType("text/html;charset=UTF-8");
    PrintWriter out=response.getWriter();
    try{
    javax.naming.Context ctx=new javax.naming.InitialContext();
    javax.sql.DataSource ds=(javax.sql.DataSource)ctx.lookup("java:/comp/env/jdbc/webdb2");
    Connection conn=ds.getConnection();

    PreparedStatement pstmt=conn.prepareStatement("select * from t_dictionary");
    
    ResultSet rs=pstmt.executeQuery();
    
    StringBuilder table=new StringBuilder();
    table.append("<table border='1'>");
    table.append("<tr><td>书名</td><td>价格</td></tr>");
    while(rs.next()){
        table.append("<tr><td>"+rs.getString("english")+"</td><td>"+rs.getString("chinese")+"</td></tr>");
    }
    table.append("</table>");
    out.println(table.toString());
    pstmt.close();
    

    }catch(Exception e){
    e.printStackTrace();
    out.println(e.getMessage());
    }
    }

  /**

  • @see HttpServlet#doPost(HttpServletRequest request, HttpServletResponse response) */ protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { // TODO Auto-generated method stub }

}

控制台错误信息：
java.sql.SQLException: Cannot create JDBC driver of class '' for connect URL 'null'
at org.apache.tomcat.dbcp.dbcp2.BasicDataSource.createConnectionFactory(BasicDataSource.java:2065)
at org.apache.tomcat.dbcp.dbcp2.BasicDataSource.createDataSource(BasicDataSource.java:1939)
at org.apache.tomcat.dbcp.dbcp2.BasicDataSource.getConnection(BasicDataSource.java:1412)
at webdemo3.chapter04.ViewDictionary.doGet(ViewDictionary.java:37)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:622)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:729)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:291)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:239)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:219)
at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:106)
at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:502)
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:142)
at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:79)
at org.apache.catalina.valves.AbstractAccessLogValve.invoke(AbstractAccessLogValve.java:617)
at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:88)
at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:518)
at org.apache.coyote.http11.AbstractHttp11Processor.process(AbstractHttp11Processor.java:1091)
at org.apache.coyote.AbstractProtocol$AbstractConnectionHandler.process(AbstractProtocol.java:668)
at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:1521)
at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.run(NioEndpoint.java:1478)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)
at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61)
at java.lang.Thread.run(Thread.java:744)
Caused by: java.sql.SQLException: No suitable driver
at java.sql.DriverManager.getDriver(DriverManager.java:315)
at org.apache.tomcat.dbcp.dbcp2.BasicDataSource.createConnectionFactory(BasicDataSource.java:2049)
... 26 more

jar包好用，在项目和tomcat都有

还有个问题一直没有解决，不知道和这个有没有关：
conn=DriverManager.getConnection("jdbc:mysql://localhost:3360/newsmanager","root","sa123456");
conn=DriverManager.getConnection("jdbc:mysql://localhost:3306/newsmanager?user=root&password=sa123456");
第一个不好使 第二个好使 为什么

Answer 1

查看getConnection的参数要求，你构造的字符串一个正确，一个不对。