已解决No suitable driver found for jdbc:mysql://localhost:3306/ 问题

05-14 924阅读

已解决No suitable driver found for jdbc:mysql://localhost:3306/ 问题

本文目录

一、Bug描述
二、定位报错点及原因
三、最终的解决方案
四、相关注意事项

总结

一、Bug描述

在学习java数据库连接池使用的时候遇到问题，无法连接到数据库，查看日志是"No Suitable Driver Found For Jdbc"，但查看数据库连接配置没问题。

java.sql.SQLException: No suitable driver found for jdbc:mysql://localhost:3306/db_mydb?characterEncoding=utf8&useSSL=false
 at java.sql.DriverManager.getConnection(Unknown Source)
 at java.sql.DriverManager.getConnection(Unknown Source)
 at com.luojia.sims.utils.DBManager.getConn(DBManager.java:30)
 at com.luojia.sims.dao.UserDAO.addUser(UserDAO.java:22)
 at org.apache.jsp.user_005fsave_jsp._jspService(user_005fsave_jsp.java:135)
 at org.apache.jasper.runtime.HttpJspBase.service(HttpJspBase.java:70)
 at javax.servlet.http.HttpServlet.service(HttpServlet.java:741)
 at org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:444)
 at org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:385)
 at org.apache.jasper.servlet.JspServlet.service(JspServlet.java:329)
 at javax.servlet.http.HttpServlet.service(HttpServlet.java:741)
 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:53)
 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:199)
 at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:96)
 at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:475)
 at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:140)
 at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:81)
 at org.apache.catalina.valves.AbstractAccessLogValve.invoke(AbstractAccessLogValve.java:651)
 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:500)
 at org.apache.coyote.AbstractProcessorLight.process(AbstractProcessorLight.java:66)
 at org.apache.coyote.AbstractProtocol$ConnectionHandler.process(AbstractProtocol.java:754)
 at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:1376)
 at org.apache.tomcat.util.net.SocketProcessorBase.run(SocketProcessorBase.java:49)
 at java.util.concurrent.ThreadPoolExecutor.runWorker(Unknown Source)
 at java.util.concurrent.ThreadPoolExecutor$Worker.run(Unknown Source)
 at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61)
 at java.lang.Thread.run(Unknown Source)
四月 08, 2018 8:07:34 下午 org.apache.catalina.core.StandardWrapperValve invoke
严重: Servlet.service() for servlet [jsp] in context with path [/sims] threw exception [An exception occurred processing [user_save.jsp] at line [23]
20:    
21:    //璋冪敤UserDAO涓殑addUser鏂规硶瀹屾垚淇濆瓨
22:    UserDTO u = new UserDTO(0,name,pwd,sex,age,remark);
23:    boolean b = new UserDAO().addUser(u);
24:    
25:    //鏍规嵁娉ㄥ唽鐘舵?佽繘琛岃烦杞?
26:    if(b){
Stacktrace:] with root cause
java.lang.NullPointerException
 at com.luojia.sims.dao.UserDAO.addUser(UserDAO.java:24)
 at org.apache.jsp.user_005fsave_jsp._jspService(user_005fsave_jsp.java:135)
 at org.apache.jasper.runtime.HttpJspBase.service(HttpJspBase.java:70)
 at javax.servlet.http.HttpServlet.service(HttpServlet.java:741)
 at org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:444)
 at org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:385)
 at org.apache.jasper.servlet.JspServlet.service(JspServlet.java:329)
 at javax.servlet.http.HttpServlet.service(HttpServlet.java:741)
 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:53)
 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:199)
 at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:96)
 at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:475)
 at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:140)
 at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:81)
 at org.apache.catalina.valves.AbstractAccessLogValve.invoke(AbstractAccessLogValve.java:651)
 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:500)
 at org.apache.coyote.AbstractProcessorLight.process(AbstractProcessorLight.java:66)
 at org.apache.coyote.AbstractProtocol$ConnectionHandler.process(AbstractProtocol.java:754)
 at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:1376)
 at org.apache.tomcat.util.net.SocketProcessorBase.run(SocketProcessorBase.java:49)
 at java.util.concurrent.ThreadPoolExecutor.runWorker(Unknown Source)
 at java.util.concurrent.ThreadPoolExecutor$Worker.run(Unknown Source)
 at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61)
 at java.lang.Thread.run(Unknown Source)

这个问题可把我愁坏了，要不问一下GPT？上。

二、定位报错点及原因

问了一下GPT，得到的答案是这样的。简单的来说，就是可能驱动程序有问题，或者是URL的问题。

三、最终的解决方案

首先，下载数据库链接的jar包：https://dev.mysql.com/downloads/connector/

进去之后找到对应好的一个jar包下载。

下载好了之后，按照路径进去，可以看到用于数据库链接的驱动 Driver.class

出现上述报错的原因通常有三种：

1、URL格式不对：正确为

Connectionconn=DriverManager.getConnection(“jdbc:mysql://localhost:3306/XX”,“root”,“XXXX”)

2、驱动字符串出错(com.mysql.jdbc.Driver)

3、Classpath中没有加入合适的mysql_jdbc驱动

那么对应的解决方案如下：

1、书写正确的URL格式

2、书写正确的驱动字符串

3、将驱动加入CLASSPATH

四、相关注意事项

总结来说解决方案如下：

1, 连接URL格式出现了问题(Connection conn=DriverManager.getConnection("jdbc:mysql://localhost:3306/XX","root","XXXX")
2, 驱动字符串出错(com.mysql.jdbc.Driver)
3, Classpath中没有加入合适的mysql_jdbc驱动
4, 尝试着将mysql-connector-java-5.1.34-bin.jar的jar包加入C:\Program Files\Java\jre1.6.0_02\lib\ext文件夹下(或者直接导入项目中),问题解决
5, 检查是不是jdbc:mysql://写成了jdbc:mysql// 连接写不对也会报这个找不到驱动的错

如果以上错误都不是，还有一种常见错误，就是jre1.8.0_162\lib\ext目录下没有加入jar包，解决办法很简单，将mysql-connector-java.jar包复制到 C:\Program Files\Java\jre1.8.0_162\lib\ext 目录下即可