Communications link failure-Mysql，网上一大推解决方法，还是不行的

Question

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

Last packet sent to the server was 1158 ms ago.
    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.jdbc.Util.handleNewInstance(Util.java:406)
    at com.mysql.jdbc.SQLError.createCommunicationsException(SQLError.java:1074)
    at com.mysql.jdbc.ConnectionImpl.createNewIO(ConnectionImpl.java:2103)
    at com.mysql.jdbc.ConnectionImpl.<init>(ConnectionImpl.java:718)
    at com.mysql.jdbc.JDBC4Connection.<init>(JDBC4Connection.java:46)
    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.jdbc.Util.handleNewInstance(Util.java:406)
    at com.mysql.jdbc.ConnectionImpl.getInstance(ConnectionImpl.java:302)
    at com.mysql.jdbc.NonRegisteringDriver.connect(NonRegisteringDriver.java:282)
    at java.sql.DriverManager.getConnection(DriverManager.java:664)
    at java.sql.DriverManager.getConnection(DriverManager.java:247)
    at com.kuang.lesson01.JdbcFristDemo.main(JdbcFristDemo.java:16)
Caused by: com.mysql.jdbc.exceptions.jdbc4.CommunicationsException: Communications link failure

Last packet sent to the server was 1158 ms ago.
    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.jdbc.Util.handleNewInstance(Util.java:406)
    at com.mysql.jdbc.SQLError.createCommunicationsException(SQLError.java:1074)
    at com.mysql.jdbc.ExportControlled.transformSocketToSSLSocket(ExportControlled.java:104)
    at com.mysql.jdbc.MysqlIO.negotiateSSLConnection(MysqlIO.java:4472)
    at com.mysql.jdbc.MysqlIO.doHandshake(MysqlIO.java:1319)
    at com.mysql.jdbc.ConnectionImpl.createNewIO(ConnectionImpl.java:2031)
    ... 12 more
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(Alerts.java:192)
    at sun.security.ssl.SSLSocketImpl.fatal(SSLSocketImpl.java:1946)
    at sun.security.ssl.Handshaker.fatalSE(Handshaker.java:316)
    at sun.security.ssl.Handshaker.fatalSE(Handshaker.java:310)
    at sun.security.ssl.ClientHandshaker.serverCertificate(ClientHandshaker.java:1640)
    at sun.security.ssl.ClientHandshaker.processMessage(ClientHandshaker.java:223)
    at sun.security.ssl.Handshaker.processLoop(Handshaker.java:1037)
    at sun.security.ssl.Handshaker.process_record(Handshaker.java:965)
    at sun.security.ssl.SSLSocketImpl.readRecord(SSLSocketImpl.java:1064)
    at sun.security.ssl.SSLSocketImpl.performInitialHandshake(SSLSocketImpl.java:1367)
    at sun.security.ssl.SSLSocketImpl.startHandshake(SSLSocketImpl.java:1395)
    at sun.security.ssl.SSLSocketImpl.startHandshake(SSLSocketImpl.java:1379)
    at com.mysql.jdbc.ExportControlled.transformSocketToSSLSocket(ExportControlled.java:89)
    ... 15 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(PKIXValidator.java:450)
    at sun.security.validator.PKIXValidator.engineValidate(PKIXValidator.java:317)
    at sun.security.validator.Validator.validate(Validator.java:262)
    at sun.security.ssl.X509TrustManagerImpl.validate(X509TrustManagerImpl.java:330)
    at sun.security.ssl.X509TrustManagerImpl.checkTrusted(X509TrustManagerImpl.java:227)
    at sun.security.ssl.X509TrustManagerImpl.checkServerTrusted(X509TrustManagerImpl.java:132)
    at sun.security.ssl.ClientHandshaker.serverCertificate(ClientHandshaker.java:1622)
    ... 23 more
Caused by: sun.security.provider.certpath.SunCertPathBuilderException: unable to find valid certification path to requested target
    at sun.security.provider.certpath.SunCertPathBuilder.build(SunCertPathBuilder.java:141)
    at sun.security.provider.certpath.SunCertPathBuilder.engineBuild(SunCertPathBuilder.java:126)
    at java.security.cert.CertPathBuilder.build(CertPathBuilder.java:280)
    at sun.security.validator.PKIXValidator.doBuild(PKIXValidator.java:445)
    ... 29 more
 

Answer 1

mysql启动了吗？端口是什么？把连接字符串发出来看看。