数据库连接异常java.net

我在下面的代码中有一个例外…我正在尝试构建一个简单的servlet项目,并且我引发了以下异常：

java.net.UnknownHostException …

我添加了mysql jar文件,除此之外……我已将其添加为外部jar文件,也在WEB-INF中的lib下添加,如

this page所述,但现在抛出java.net.UnknownHostException.

这是代码和异常堆栈跟踪.

package com.servlet.Mysql;

import java.sql.Connection;

import java.sql.DriverManager;

import java.sql.SQLException;

public class Connection_Class {

String driver_ClassName="com.mysql.jdbc.Driver";

String URL_connection="jdbc:mysql://localhost3306/vendor";

String user="root";

String password="lifesuckzz";

private static Connection_Class connectionclass=null;

private Connection_Class(){

try{

Class.forName(driver_ClassName);

}catch(ClassNotFoundException e){

e.printStackTrace();

}

public Connection getConnection() throws SQLException{

Connection con=null;

con=DriverManager.getConnection(URL_connection,user,password);

return con;

}

public static Connection_Class getInstance(){

if(connectionclass==null){

connectionclass=new Connection_Class();

}

return connectionclass;}}

堆栈跟踪：

com.mysql.jdbc.CommunicationsException: Communications link failure due to underlying exception:

** BEGIN NESTED EXCEPTION **

java.net.UnknownHostException

MESSAGE: localhost3306

STACKTRACE:

java.net.UnknownHostException: localhost3306

at java.net.Inet6AddressImpl.lookupAllHostAddr(Native Method)

at java.net.InetAddress$1.lookupAllHostAddr(Unknown Source)

at java.net.InetAddress.getAddressesFromNameService(Unknown Source)

at java.net.InetAddress.getAllByName0(Unknown Source)

at java.net.InetAddress.getAllByName(Unknown Source)

at com.mysql.jdbc.StandardSocketFactory.connect(StandardSocketFactory.java:133)

at com.mysql.jdbc.MysqlIO.(MysqlIO.java:280)

at com.mysql.jdbc.Connection.createNewIO(Connection.java:1699)

at com.mysql.jdbc.Connection.(Connection.java:405)

at com.mysql.jdbc.NonRegisteringDriver.connect(NonRegisteringDriver.java:268)

at java.sql.DriverManager.getConnection(Unknown Source)

at com.servlet.Mysql.Connection_Class.getConnection(Connection_Class.java:25)

at com.servlet.Mysql.LoginServlet.doGet(LoginServlet.java:49)

at javax.servlet.http.HttpServlet.service(HttpServlet.java:621)

at javax.servlet.http.HttpServlet.service(HttpServlet.java:728)

at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:305)

at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:210)

at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:222)

at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:123)

at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:472)

at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:171)

at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:99)

at org.apache.catalina.valves.AccessLogValve.invoke(AccessLogValve.java:936)

at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:118)

at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:407)

at org.apache.coyote.http11.AbstractHttp11Processor.process(AbstractHttp11Processor.java:1004)

at org.apache.coyote.AbstractProtocol$AbstractConnectionHandler.process(AbstractProtocol.java:589)

at org.apache.tomcat.util.net.JIoEndpoint$SocketProcessor.run(JIoEndpoint.java:310)

at java.util.concurrent.ThreadPoolExecutor.runWorker(Unknown Source)

at java.util.concurrent.ThreadPoolExecutor$Worker.run(Unknown Source)

at java.lang.Thread.run(Unknown Source)

** END NESTED EXCEPTION **

at com.mysql.jdbc.Connection.createNewIO(Connection.java:1764)