java - JDBC 无法连接到 MySQL DB

Question

情况

我正在尝试构建一个简单的 JavaEE 应用程序。我在 WSL 中运行 MySQL 数据库，并在 Windows 中通过 IntelliJ 配置 TomEE。我之前已成功连接到此设置中的数据库。在继续开发我的应用程序并重新部署以测试进度后，我突然开始收到“通信链接故障”异常。我的 pom.xml 或有关连接的代码没有任何变化。WSL 终端中的 Netstat 命令显示 MySQL 正在侦听预期端口。

IntelliJ 控制台中的错误消息

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 java.base/jdk.internal.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
    at java.base/jdk.internal.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:62)
    at java.base/jdk.internal.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45)
    at java.base/java.lang.reflect.Constructor.newInstanceWithCaller(Constructor.java:500)
    at java.base/java.lang.reflect.Constructor.newInstance(Constructor.java:481)
    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:89)
    at com.mysql.cj.NativeSession.connect(NativeSession.java:144)
    at com.mysql.cj.jdbc.ConnectionImpl.connectOneTryOnly(ConnectionImpl.java:953)
    at com.mysql.cj.jdbc.ConnectionImpl.createNewIO(ConnectionImpl.java:823)
    ... 49 more
Caused by: java.net.ConnectException: Connection refused: connect
    at java.base/java.net.PlainSocketImpl.connect0(Native Method)
    at java.base/java.net.PlainSocketImpl.socketConnect(PlainSocketImpl.java:101)
    at java.base/java.net.AbstractPlainSocketImpl.doConnect(AbstractPlainSocketImpl.java:399)
    at java.base/java.net.AbstractPlainSocketImpl.connectToAddress(AbstractPlainSocketImpl.java:242)
    at java.base/java.net.AbstractPlainSocketImpl.connect(AbstractPlainSocketImpl.java:224)
    at java.base/java.net.SocksSocketImpl.connect(SocksSocketImpl.java:403)
    at java.base/java.net.Socket.connect(Socket.java:591)
    at com.mysql.cj.protocol.StandardSocketFactory.connect(StandardSocketFactory.java:155)
    at com.mysql.cj.protocol.a.NativeSocketConnection.connect(NativeSocketConnection.java:63)
    ... 52 more

连接代码

public Connection getConnection() throws RuntimeException {

        try {
            DatabaseProperties props = new DatabaseProperties();

            var url = props.getUrl();
            var host = props.getHost();
            var password = props.getPassword();

            Class.forName("com.mysql.cj.jdbc.Driver");
            return DriverManager.getConnection(url, host, password);
        } catch (Exception e) {
            e.printStackTrace();
            throw new RuntimeException();
        }

    }

database.properties 文件

url = jdbc:mysql://127.0.0.1:3306/spotitube
host = root
password = wachtwoord

pom依赖

   <dependency>
      <groupId>mysql</groupId>
      <artifactId>mysql-connector-java</artifactId>
      <version>8.0.23</version>
    </dependency>

输出 - netstat -tulnp

(No info could be read for "-p": geteuid()=1000 but you should be root.)
Active Internet connections (only servers)
Proto Recv-Q Send-Q Local Address           Foreign Address         State       PID/Program name
tcp        0      0 127.0.0.1:3306          0.0.0.0:*               LISTEN      -
tcp        0      0 127.0.0.1:33060         0.0.0.0:*               LISTEN      -

输出 - sudo 服务 mysql 状态

 /usr/bin/mysqladmin  Ver 8.0.23-0ubuntu0.20.04.1 for Linux on x86_64 ((Ubuntu))
Copyright (c) 2000, 2021, Oracle and/or its affiliates.

Oracle is a registered trademark of Oracle Corporation and/or its
affiliates. Other names may be trademarks of their respective
owners.

Server version          8.0.23-0ubuntu0.20.04.1
Protocol version        10
Connection              Localhost via UNIX socket
UNIX socket             /var/run/mysqld/mysqld.sock
Uptime:                 23 min 33 sec

怎么办？

我试过了：

• 重新启动 MySQL 服务器
• 重启 TomEE 服务器
• mvn 清洁

没有任何帮助。正如我之前所说，此代码和设置之前有效。有人知道我可以尝试什么吗？

标签： javamysqljdbc