报错Communications link failure

package com.bbwan.jdbc;

import java.sql.Connection;

import java.sql.DriverManager;

import java.sql.ResultSet;

import java.sql.SQLException;

import java.sql.Statement;

import org.junit.Test;

public class JDBCDemo1 {

@Test

public void demo1() {

Connection conn=null;

Statement state=null;

ResultSet set=null;

try {

//1.加载驱动

Class.forName("com.mysql.cj.jdbc.Driver");

//2.获得连接

conn=DriverManager.getConnection("jdbc:mysql://localhost:3306/jdbctest"+"?useSSL=false&serverTimezone=Hongkong&useUnicode-=true&characterEncoding=utf-8","root","bbwan");

//3.创建执行sql语句的对象，执行sql语句

String sql="select * from user";

state=conn.createStatement();

set= state.executeQuery(sql);

while (set.next()) {

int uid=set.getInt("uid");

String username=set.getString("username");

String password=set.getString("password");

String name=set.getString("name");

System.out.println(uid+"|"+username+"|"+password+"|"+name);

}

set.close();

state.close();

conn.close();

//4.释放资源

} catch (ClassNotFoundException e) {

// TODO Auto-generated catch block

e.printStackTrace();

}catch (SQLException 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:174)

at com.mysql.cj.jdbc.exceptions.SQLExceptionsMapping.translateException(SQLExceptionsMapping.java:64)

at com.mysql.cj.jdbc.ConnectionImpl.createNewIO(ConnectionImpl.java:835)

at com.mysql.cj.jdbc.ConnectionImpl.<init>(ConnectionImpl.java:455)

at com.mysql.cj.jdbc.ConnectionImpl.getInstance(ConnectionImpl.java:240)

at com.mysql.cj.jdbc.NonRegisteringDriver.connect(NonRegisteringDriver.java:199)

at java.sql.DriverManager.getConnection(DriverManager.java:664)

at java.sql.DriverManager.getConnection(DriverManager.java:247)

at com.bbwan.jdbc.JDBCDemo1.demo1(JDBCDemo1.java:23)

at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)

at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)

at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)

at java.lang.reflect.Method.invoke(Method.java:498)

at org.junit.runners.model.FrameworkMethod$1.runReflectiveCall(FrameworkMethod.java:50)

at org.junit.internal.runners.model.ReflectiveCallable.run(ReflectiveCallable.java:12)

at org.junit.runners.model.FrameworkMethod.invokeExplosively(FrameworkMethod.java:47)

at org.junit.internal.runners.statements.InvokeMethod.evaluate(InvokeMethod.java:17)

at org.junit.runners.ParentRunner.runLeaf(ParentRunner.java:325)

at org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:78)

at org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:57)

at org.junit.runners.ParentRunner$3.run(ParentRunner.java:290)

at org.junit.runners.ParentRunner$1.schedule(ParentRunner.java:71)

at org.junit.runners.ParentRunner.runChildren(ParentRunner.java:288)

at org.junit.runners.ParentRunner.access$000(ParentRunner.java:58)

at org.junit.runners.ParentRunner$2.evaluate(ParentRunner.java:268)

at org.junit.runners.ParentRunner.run(ParentRunner.java:363)

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(NativeConstructorAccessorImpl.java:62)

at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45)

at java.lang.reflect.Constructor.newInstance(Constructor.java:423)

at com.mysql.cj.exceptions.ExceptionFactory.createException(ExceptionFactory.java:61)

at com.mysql.cj.exceptions.ExceptionFactory.createException(ExceptionFactory.java:105)

at com.mysql.cj.exceptions.ExceptionFactory.createException(ExceptionFactory.java:151)

at com.mysql.cj.exceptions.ExceptionFactory.createCommunicationsException(ExceptionFactory.java:167)

at com.mysql.cj.protocol.a.NativeSocketConnection.connect(NativeSocketConnection.java:91)

at com.mysql.cj.NativeSession.connect(NativeSession.java:152)

at com.mysql.cj.jdbc.ConnectionImpl.connectOneTryOnly(ConnectionImpl.java:955)

at com.mysql.cj.jdbc.ConnectionImpl.createNewIO(ConnectionImpl.java:825)

... 29 more

Caused by: java.net.UnknownHostException: locathost

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

at java.net.InetAddress$2.lookupAllHostAddr(InetAddress.java:928)

at java.net.InetAddress.getAddressesFromNameService(InetAddress.java:1323)

at java.net.InetAddress.getAllByName0(InetAddress.java:1276)

at java.net.InetAddress.getAllByName(InetAddress.java:1192)

at java.net.InetAddress.getAllByName(InetAddress.java:1126)

at com.mysql.cj.protocol.StandardSocketFactory.connect(StandardSocketFactory.java:132)

at com.mysql.cj.protocol.a.NativeSocketConnection.connect(NativeSocketConnection.java:65)

... 32 more