我这好像是驱动出问题了,怎么弄
package com.imooc.jdbc.demo1;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;
import org.junit.Test;
import com.mysql.jdbc.Driver;
public class JDBCDemo1 {
@Test
/*
* JDBC的入门程序
* */
public void demo1() {
try {
//1.加载驱动
Class.forName("com.mysql.cj.jdbc.Driver");
//2.获得连接
Connection conn =DriverManager.getConnection(
"jdbc:mysql:///jdbctest"
+"?useSSL=false&serverTimezone=Hongkong&useUnicode=true&characterEncoding=utf-8",
"root","root");
//3.创建执行SQL语句的对象,并且执行SQL
//3.1创建执行sql的对象
String sql ="select*from user";
Statement stmt =conn.createStatement();
//3.2执行sql
ResultSet resultSet =stmt.executeQuery(sql);
while(resultSet.next()) {
int uid =resultSet.getInt("uid");
String username =resultSet.getString("username");
String password =resultSet.getString("password");
String name =resultSet.getString("name");
System.out.println(uid+" "+username+" "+password+" "+name);
}
//4.释放资源
resultSet.close();
stmt.close();
conn.close();
} catch (SQLException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (ClassNotFoundException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
}
com.mysql.cj.jdbc.exceptions.CommunicationsException: Communications link failure
The last packet sent successfully to the server was 0 milliseconds ago. The driver has not received any packets from the server.
at com.mysql.cj.jdbc.exceptions.SQLError.createCommunicationsException(SQLError.java:172)
at com.mysql.cj.jdbc.exceptions.SQLExceptionsMapping.translateException(SQLExceptionsMapping.java:64)
at com.mysql.cj.jdbc.ConnectionImpl.createNewIO(ConnectionImpl.java:862)
at com.mysql.cj.jdbc.ConnectionImpl.<init>(ConnectionImpl.java:444)
at com.mysql.cj.jdbc.ConnectionImpl.getInstance(ConnectionImpl.java:230)
at com.mysql.cj.jdbc.NonRegisteringDriver.connect(NonRegisteringDriver.java:226)
at java.sql.DriverManager.getConnection(Unknown Source)
at java.sql.DriverManager.getConnection(Unknown Source)
at com.imooc.jdbc.demo1.JDBCDemo1.demo1(JDBCDemo1.java:25)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
at java.lang.reflect.Method.invoke(Unknown Source)
at org.junit.runners.model.FrameworkMethod$1.runReflectiveCall(FrameworkMethod.java:47)
at org.junit.internal.runners.model.ReflectiveCallable.run(ReflectiveCallable.java:12)
at org.junit.runners.model.FrameworkMethod.invokeExplosively(FrameworkMethod.java:44)
at org.junit.internal.runners.statements.InvokeMethod.evaluate(InvokeMethod.java:17)
at org.junit.runners.ParentRunner.runLeaf(ParentRunner.java:271)
at org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:70)
at org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:50)
at org.junit.runners.ParentRunner$3.run(ParentRunner.java:238)
at org.junit.runners.ParentRunner$1.schedule(ParentRunner.java:63)
at org.junit.runners.ParentRunner.runChildren(ParentRunner.java:236)
at org.junit.runners.ParentRunner.access$000(ParentRunner.java:53)
at org.junit.runners.ParentRunner$2.evaluate(ParentRunner.java:229)
at org.junit.runners.ParentRunner.run(ParentRunner.java:309)
at org.eclipse.jdt.internal.junit4.runner.JUnit4TestReference.run(JUnit4TestReference.java:89)
at org.eclipse.jdt.internal.junit.runner.TestExecution.run(TestExecution.java:41)
at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:541)
at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:763)
at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.run(RemoteTestRunner.java:463)
at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.main(RemoteTestRunner.java:209)
Caused by: com.mysql.cj.exceptions.CJCommunicationsException: Communications link failure
The last packet sent successfully to the server was 0 milliseconds ago. The driver has not received any packets from the server.
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.cj.exceptions.ExceptionFactory.createException(ExceptionFactory.java:59)
at com.mysql.cj.exceptions.ExceptionFactory.createException(ExceptionFactory.java:103)
at com.mysql.cj.exceptions.ExceptionFactory.createException(ExceptionFactory.java:149)
at com.mysql.cj.exceptions.ExceptionFactory.createCommunicationsException(ExceptionFactory.java:165)
at com.mysql.cj.protocol.a.NativeSocketConnection.connect(NativeSocketConnection.java:92)
at com.mysql.cj.NativeSession.connect(NativeSession.java:152)
at com.mysql.cj.jdbc.ConnectionImpl.connectOneTryOnly(ConnectionImpl.java:982)
at com.mysql.cj.jdbc.ConnectionImpl.createNewIO(ConnectionImpl.java:852)
... 29 more
Caused by: java.net.ConnectException: Connection timed out: connect
at java.net.DualStackPlainSocketImpl.connect0(Native Method)
at java.net.DualStackPlainSocketImpl.socketConnect(Unknown Source)
at java.net.AbstractPlainSocketImpl.doConnect(Unknown Source)
at java.net.AbstractPlainSocketImpl.connectToAddress(Unknown Source)
at java.net.AbstractPlainSocketImpl.connect(Unknown Source)
at java.net.PlainSocketImpl.connect(Unknown Source)
at java.net.SocksSocketImpl.connect(Unknown Source)
at java.net.Socket.connect(Unknown Source)
at com.mysql.cj.protocol.StandardSocketFactory.connect(StandardSocketFactory.java:173)
at com.mysql.cj.protocol.a.NativeSocketConnection.connect(NativeSocketConnection.java:66)
... 32 more
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