jdbc连接数据库时报错

Exception in thread "main" com.mysql.jdbc.exceptions.jdbc4.CommunicationsException: Communications link failure

The last packet successfully received from the server was 920 milliseconds ago.  The last packet sent successfully to the server was 916 milliseconds ago.
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:404)
at com.mysql.jdbc.SQLError.createCommunicationsException(SQLError.java:988)
at com.mysql.jdbc.ExportControlled.transformSocketToSSLSocket(ExportControlled.java:164)
at com.mysql.jdbc.MysqlIO.negotiateSSLConnection(MysqlIO.java:4894)
at com.mysql.jdbc.MysqlIO.proceedHandshakeWithPluggableAuthentication(MysqlIO.java:1661)
at com.mysql.jdbc.MysqlIO.doHandshake(MysqlIO.java:1228)
at com.mysql.jdbc.ConnectionImpl.coreConnect(ConnectionImpl.java:2253)
at com.mysql.jdbc.ConnectionImpl.connectOneTryOnly(ConnectionImpl.java:2284)
at com.mysql.jdbc.ConnectionImpl.createNewIO(ConnectionImpl.java:2083)
at com.mysql.jdbc.ConnectionImpl.<init>(ConnectionImpl.java:806)
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:404)
at com.mysql.jdbc.ConnectionImpl.getInstance(ConnectionImpl.java:410)
at com.mysql.jdbc.NonRegisteringDriver.connect(NonRegisteringDriver.java:328)
at java.sql.DriverManager.getConnection(Unknown Source)
at java.sql.DriverManager.getConnection(Unknown Source)
at Test.main(Test.java:8)
Caused by: javax.net.ssl.SSLHandshakeException: sun.security.validator.ValidatorException: PKIX path building failed: sun.security.provider.certpath.SunCertPathBuilderException: unable to find valid certification path to requested target
at sun.security.ssl.Alerts.getSSLException(Unknown Source)
at sun.security.ssl.SSLSocketImpl.fatal(Unknown Source)
at sun.security.ssl.Handshaker.fatalSE(Unknown Source)
at sun.security.ssl.Handshaker.fatalSE(Unknown Source)
at sun.security.ssl.ClientHandshaker.serverCertificate(Unknown Source)
at sun.security.ssl.ClientHandshaker.processMessage(Unknown Source)
at sun.security.ssl.Handshaker.processLoop(Unknown Source)
at sun.security.ssl.Handshaker.process_record(Unknown Source)
at sun.security.ssl.SSLSocketImpl.readRecord(Unknown Source)
at sun.security.ssl.SSLSocketImpl.performInitialHandshake(Unknown Source)
at sun.security.ssl.SSLSocketImpl.startHandshake(Unknown Source)
at sun.security.ssl.SSLSocketImpl.startHandshake(Unknown Source)
at com.mysql.jdbc.ExportControlled.transformSocketToSSLSocket(ExportControlled.java:149)
... 18 more
Caused by: sun.security.validator.ValidatorException: PKIX path building failed: sun.security.provider.certpath.SunCertPathBuilderException: unable to find valid certification path to requested target
at sun.security.validator.PKIXValidator.doBuild(Unknown Source)
at sun.security.validator.PKIXValidator.engineValidate(Unknown Source)
at sun.security.validator.Validator.validate(Unknown Source)
at sun.security.ssl.X509TrustManagerImpl.validate(Unknown Source)
at sun.security.ssl.X509TrustManagerImpl.checkTrusted(Unknown Source)
at sun.security.ssl.X509TrustManagerImpl.checkServerTrusted(Unknown Source)
... 27 more
Caused by: sun.security.provider.certpath.SunCertPathBuilderException: unable to find valid certification path to requested target
at sun.security.provider.certpath.SunCertPathBuilder.build(Unknown Source)
at sun.security.provider.certpath.SunCertPathBuilder.engineBuild(Unknown Source)
at java.security.cert.CertPathBuilder.build(Unknown Source)
... 33 more

8 个解决方案

#1

用Navicat可以对数据库进行正常操作
是安装数据库时哪里设置错了么

#2

代码贴出来，这样怎么看

#3

import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.SQLException;

public class Test {
	public static void main(String[] args) throws ClassNotFoundException, SQLException {
		Class.forName("com.mysql.jdbc.Driver");
		Connection con = DriverManager.getConnection("jdbc:mysql://localhost:3306/band2?useSSL=true","sa","123456");
	}
}

#4

引用 2 楼 LUUUUU_IT 的回复:

代码贴出来，这样怎么看

代码贴出来了，只是很短的两行

#5

修改mysql/etc/my.cnf中的参数wait_timeout为更长的时间，修改后需要重启mysql服务。
或者从新启动eclipse

试一下

#6

引用 5 楼 lachieOfCSDN 的回复:

修改mysql/etc/my.cnf中的参数wait_timeout为更长的时间，修改后需要重启mysql服务。
或者从新启动eclipse

试一下

超时时间显示这个，还是会报异常

#7

useSSL=false

#8

引用 7 楼 yjsl__ 的回复:

useSSL=false

Sun Jun 03 14:00:30 CST 2018 WARN: Establishing SSL connection without server's identity verification is not recommended. According to MySQL 5.5.45+, 5.6.26+ and 5.7.6+ requirements SSL connection must be established by default if explicit option isn't set. For compliance with existing applications not using SSL the verifyServerCertificate property is set to 'false'. You need either to explicitly disable SSL by setting useSSL=false, or set useSSL=true and provide truststore for server certificate verification.
Exception in thread "main" com.mysql.jdbc.exceptions.jdbc4.MySQLNonTransientConnectionException: Could not create connection to database 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.jdbc.Util.handleNewInstance(Util.java:404)
	at com.mysql.jdbc.Util.getInstance(Util.java:387)
	at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:917)
	at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:896)
	at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:885)
	at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:860)
	at com.mysql.jdbc.ConnectionImpl.connectOneTryOnly(ConnectionImpl.java:2330)
	at com.mysql.jdbc.ConnectionImpl.createNewIO(ConnectionImpl.java:2083)
	at com.mysql.jdbc.ConnectionImpl.<init>(ConnectionImpl.java:806)
	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:404)
	at com.mysql.jdbc.ConnectionImpl.getInstance(ConnectionImpl.java:410)
	at com.mysql.jdbc.NonRegisteringDriver.connect(NonRegisteringDriver.java:328)
	at java.sql.DriverManager.getConnection(Unknown Source)
	at java.sql.DriverManager.getConnection(Unknown Source)
	at Test.main(Test.java:8)
Caused by: java.lang.NullPointerException
	at com.mysql.jdbc.ConnectionImpl.getServerCharset(ConnectionImpl.java:2997)
	at com.mysql.jdbc.MysqlIO.sendConnectionAttributes(MysqlIO.java:1936)
	at com.mysql.jdbc.MysqlIO.proceedHandshakeWithPluggableAuthentication(MysqlIO.java:1865)
	at com.mysql.jdbc.MysqlIO.doHandshake(MysqlIO.java:1228)
	at com.mysql.jdbc.ConnectionImpl.coreConnect(ConnectionImpl.java:2253)
	at com.mysql.jdbc.ConnectionImpl.connectOneTryOnly(ConnectionImpl.java:2284)
	... 13 more

又出了个新的异常信息