我目前正在通过视频教程学习 Servlet 和 Jsp，我正在尝试连接到 MySql 数据库，但这样做很困难，我已经按照教程中采取的所有步骤进行操作，但它仍然没有连接，起初我得到的异常是 java.sql.SQLException：在 java.sql.DriverManager 找不到适合 com.mysql.jdbc.Driver 的驱动程序
我已经在线检查了一个可能的解决方案，但没有一个对我有用，现在我将 MySQL-connector-java-5.1.49-bin.jar 添加到库中，并带来了另一种类型的异常。
java.sql.SQLException: Cannot create PoolableConnectionFactory (Public Key Retrieval is not allowed)
at org.apache.tomcat.dbcp.dbcp2.BasicDataSource.createPoolableConnectionFactory(BasicDataSource.java:669)
at org.apache.tomcat.dbcp.dbcp2.BasicDataSource.createDataSource(BasicDataSource.java:544)
at org.apache.tomcat.dbcp.dbcp2.BasicDataSource.getConnection(BasicDataSource.java:753)
at com.luv2code.web.jdbc.TextSerlets.doGet(TextSerlets.java:43)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:634)
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:202)
at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:96)
at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:541)
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:139)
at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:92)
at org.apache.catalina.valves.AbstractAccessLogValve.invoke(AbstractAccessLogValve.java:690)
at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:74)
at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:343)
at org.apache.coyote.http11.Http11Processor.service(Http11Processor.java:373)
at org.apache.coyote.AbstractProcessorLight.process(AbstractProcessorLight.java:65)
at org.apache.coyote.AbstractProtocol$ConnectionHandler.process(AbstractProtocol.java:868)
at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:1590)
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)
Caused by: com.mysql.jdbc.exceptions.jdbc4.MySQLNonTransientConnectionException: Public Key Retrieval is not allowed
at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
at sun.reflect.NativeConstructorAccessorImpl.newInstance(Unknown Source)
at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(Unknown Source)
at java.lang.reflect.Constructor.newInstance(Unknown Source)
at com.mysql.jdbc.Util.handleNewInstance(Util.java:403)
at com.mysql.jdbc.Util.getInstance(Util.java:386)
at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:919)
at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:898)
at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:887)
at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:861)
at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:878)
at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:874)
at com.mysql.jdbc.MysqlIO.proceedHandshakeWithPluggableAuthentication(MysqlIO.java:1770)
at com.mysql.jdbc.MysqlIO.doHandshake(MysqlIO.java:1217)
at com.mysql.jdbc.ConnectionImpl.coreConnect(ConnectionImpl.java:2189)
at com.mysql.jdbc.ConnectionImpl.connectOneTryOnly(ConnectionImpl.java:2220)
at com.mysql.jdbc.ConnectionImpl.createNewIO(ConnectionImpl.java:2015)
at com.mysql.jdbc.ConnectionImpl.<init>(ConnectionImpl.java:768)
at com.mysql.jdbc.JDBC4Connection.<init>(JDBC4Connection.java:47)
at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
at sun.reflect.NativeConstructorAccessorImpl.newInstance(Unknown Source)
at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(Unknown Source)
at java.lang.reflect.Constructor.newInstance(Unknown Source)
at com.mysql.jdbc.Util.handleNewInstance(Util.java:403)
at com.mysql.jdbc.ConnectionImpl.getInstance(ConnectionImpl.java:385)
at com.mysql.jdbc.NonRegisteringDriver.connect(NonRegisteringDriver.java:323)
at org.apache.tomcat.dbcp.dbcp2.DriverConnectionFactory.createConnection(DriverConnectionFactory.java:55)
at org.apache.tomcat.dbcp.dbcp2.PoolableConnectionFactory.makeObject(PoolableConnectionFactory.java:355)
at org.apache.tomcat.dbcp.dbcp2.BasicDataSource.validateConnectionFactory(BasicDataSource.java:115)
at org.apache.tomcat.dbcp.dbcp2.BasicDataSource.createPoolableConnectionFactory(BasicDataSource.java:665)
... 27 more
Caused by: com.mysql.jdbc.exceptions.jdbc4.MySQLNonTransientConnectionException: Public Key Retrieval is not allowed
at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
at sun.reflect.NativeConstructorAccessorImpl.newInstance(Unknown Source)
at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(Unknown Source)
at java.lang.reflect.Constructor.newInstance(Unknown Source)
at com.mysql.jdbc.Util.handleNewInstance(Util.java:403)
at com.mysql.jdbc.Util.getInstance(Util.java:386)
at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:919)
at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:898)
at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:887)
at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:861)
at com.mysql.jdbc.authentication.CachingSha2PasswordPlugin.nextAuthenticationStep(CachingSha2PasswordPlugin.java:130)
at com.mysql.jdbc.MysqlIO.proceedHandshakeWithPluggableAuthentication(MysqlIO.java:1768)
... 44 more
我有点沮丧，因为它会影响我的学习进度，下面是我的上下文.xml文件，我还必须说它现在显示了在第 1 行错误中发现的某种多重注释。
<Context>
<Resource name="jdbc/web_student_tracker"
auth="Container" type="javax.sql.DataSource"
maxActive="20" maxIdle="5" maxWait="10000"
username="webstudent" password="webstudent"
driverClassName="com.mysql.jdbc.Driver"
url="jdbc:mysql://localhost:3306/web_student_tracker?useSSL=false"/>
</Context>
我的servlet代码：
package com.luv2code.web.jdbc;
import java.io.IOException;
import java.io.PrintWriter;
import java.sql.Connection;
import java.sql.ResultSet;
import java.sql.Statement;
import javax.annotation.Resource;
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 javax.sql.DataSource;
/**
* Servlet implementation class TextSerlets
*/
@WebServlet("/TextSerlets")
public class TextSerlets extends HttpServlet {
private static final long serialVersionUID = 1L;
@Resource(name="jdbc/web_student_tracker")
private DataSource dataSource;
/**
* @see HttpServlet#doGet(HttpServletRequest request, HttpServletResponse response)
*/
protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
//step 1 : Set up print writer
PrintWriter out = response.getWriter();
response.setContentType("text/plain");
//step 2: Get a cinnection to the adatbase
Connection myConn = null;
Statement myStmt = null;
ResultSet myRs = null;
try {
myConn = dataSource.getConnection();
//Step 3 :Create a SQL statement
String sql = "select * from student";
myStmt = myConn.createStatement();
//step 4: Execute SQL query
myRs = myStmt.executeQuery(sql);
//step 5 : Process the result set
while (myRs.next()) {
String email = myRs.getString("email");
out.println(email);
}
}
catch (Exception exc) {
exc.printStackTrace();
}
}
}
这是我第一次在这里发帖，所以如果有的话，请忽略帖子上出现的任何错误。
您应该添加allowPublicKeyRetrieval=true以允许客户端自动从服务器请求公钥。请注意，不建议使用allowPublicKeyRetrieval=true，因为它可能允许恶意代理执行 MITM 攻击以获取明文密码。改变
url="jdbc:mysql://localhost:3306/web_student_tracker?useSSL=false"
自
url="jdbc:mysql://localhost:3306/web_student_tracker?allowPublicKeyRetrieval=true&useSSL=false;"
所以我删除了整个 Web 项目并创建了一个新项目，现在看来这个url="jdbc:mysql://localhost:3306/web_student_tracker?useSSL=false"工作正常