MySQL与JAVA错误.成功发送到服务器的最后一个数据包是在0毫秒前 [英] MySql with JAVA error. The last packet sent successfully to the server was 0 milliseconds ago

问题描述

我已经阅读了很多有关此异常的信息，但是我无法解决.

I have read about this exception a lot, but I can't solve my.

Mysql服务器正在工作.

Mysql server is working.

我可以从NetBeans连接到它，但是不能从Java代码连接到它.

I can connect to it from NetBeans, but I can't connect to it from java code.

Exception in thread "main" com.mysql.jdbc.exceptions.jdbc4.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 sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
    at sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:57)
    at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45)
    at java.lang.reflect.Constructor.newInstance(Constructor.java:525)
    at com.mysql.jdbc.Util.handleNewInstance(Util.java:411)
    at com.mysql.jdbc.SQLError.createCommunicationsException(SQLError.java:1116)
    at com.mysql.jdbc.MysqlIO.<init>(MysqlIO.java:344)
    at com.mysql.jdbc.ConnectionImpl.coreConnect(ConnectionImpl.java:2332)
    at com.mysql.jdbc.ConnectionImpl.connectOneTryOnly(ConnectionImpl.java:2369)
    at com.mysql.jdbc.ConnectionImpl.createNewIO(ConnectionImpl.java:2153)
    at com.mysql.jdbc.ConnectionImpl.<init>(ConnectionImpl.java:792)
    at com.mysql.jdbc.JDBC4Connection.<init>(JDBC4Connection.java:47)
    at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
    at sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:57)
    at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45)
    at java.lang.reflect.Constructor.newInstance(Constructor.java:525)
    at com.mysql.jdbc.Util.handleNewInstance(Util.java:411)
    at com.mysql.jdbc.ConnectionImpl.getInstance(ConnectionImpl.java:381)
    at com.mysql.jdbc.NonRegisteringDriver.connect(NonRegisteringDriver.java:305)
    at java.sql.DriverManager.getConnection(DriverManager.java:579)
    at java.sql.DriverManager.getConnection(DriverManager.java:243)
    at javaapplication3.JavaApplication3.main(JavaApplication3.java:32)
Caused by: java.net.SocketException: Permission denied: connect
    at java.net.DualStackPlainSocketImpl.connect0(Native Method)
    at java.net.DualStackPlainSocketImpl.socketConnect(DualStackPlainSocketImpl.java:69)
    at java.net.AbstractPlainSocketImpl.doConnect(AbstractPlainSocketImpl.java:339)
    at java.net.AbstractPlainSocketImpl.connectToAddress(AbstractPlainSocketImpl.java:200)
    at java.net.AbstractPlainSocketImpl.connect(AbstractPlainSocketImpl.java:182)
    at java.net.PlainSocketImpl.connect(PlainSocketImpl.java:157)
    at java.net.SocksSocketImpl.connect(SocksSocketImpl.java:391)
    at java.net.Socket.connect(Socket.java:579)
    at java.net.Socket.connect(Socket.java:528)
    at java.net.Socket.<init>(Socket.java:425)
    at java.net.Socket.<init>(Socket.java:241)
    at com.mysql.jdbc.StandardSocketFactory.connect(StandardSocketFactory.java:257)
    at com.mysql.jdbc.MysqlIO.<init>(MysqlIO.java:294)
    ... 15 more
Java Result: 1

我可以通过任何方式从Java代码连接到Mysql捕获此异常，但是从MysqlWorkBench和NetBeans都可以. 我没有防火墙.我尝试了127.0.0.1，结果是一样的.

I catch this exception with any ways to connect to Mysql from java code, but from MysqlWorkBench and from NetBeans is OK. I have no Firewall. I tried 127.0.0.1, result is the same.

推荐答案

尝试在

conn = DriverManager.getConnection("jdbc:mysql://localhost/mysql?"
                                        + "user=root&password=onelife");

我认为您应该有这样的东西:

I think you should have something like this:

conn = DriverManager.getConnection("jdbc:mysql://localhost:3306/mysql?"
                                            + "user=root&password=onelife");

此外，示例中的端口号(3306)是默认端口，但是您可以在安装MySQL时更改它.

Also, the port number in my example (3306) is the default port, but you may change it while installing MySQL.

我认为，指定密码和用户的更好方法是像这样将其与URL分开:

I think that a better way to specify password and user is to separate them from the URL like this:

connection = DriverManager.getConnection(url, login, password);

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