我想创建一个测试来检索/更新数据库条目。我是自动化测试的新手，从未使用过与数据库的连接。为此，我与用户和密码建立了本地连接，并安装了 Northwind 数据库。在 SQL Server Management Studio 中一切正常，但在我尝试运行的以下测试中未建立与数据库的连接：
import java.sql.*;
public class Driver {
public static void main(String[] args) {
try {
Connection myConn = DriverManager.getConnection("jdbc:mysql://localhost:1433/Northwind", "coconut", "P@ssw0rd123");
// 1.Get a connection to database
// Create a statement
Statement myStmt = myConn.createStatement();
// Execute sql query
ResultSet myRs = myStmt.executeQuery("select * from Employees");
// Process result set
while (myRs.next()){
System.out.println(myRs.getString("LastName"));
}
} catch (Exception exc) {
exc.printStackTrace();
}
}
}
检查不同的教程后，我在项目模块中配置了相应的 jar：mysql-connector-java-8.0.21 sqljdbc4-2.0
在 Sql Server 配置管理器中，我喜欢 SQL 正在侦听端口 1433，这就是我在连接 url 中指定它的原因）
运行上述代码时，我收到以下错误：com.mysql.cj.jdbc.exceptions.CommunicationsException: Communications link failure
吨
he 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:836)
at com.mysql.cj.jdbc.ConnectionImpl.<init>(ConnectionImpl.java:456)
at com.mysql.cj.jdbc.ConnectionImpl.getInstance(ConnectionImpl.java:246)
at com.mysql.cj.jdbc.NonRegisteringDriver.connect(NonRegisteringDriver.java:197)
at java.sql/java.sql.DriverManager.getConnection(DriverManager.java:677)
at java.sql/java.sql.DriverManager.getConnection(DriverManager.java:228)
at Driver.main(Driver.java:8)
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:91)
at com.mysql.cj.NativeSession.connect(NativeSession.java:144)
at com.mysql.cj.jdbc.ConnectionImpl.connectOneTryOnly(ConnectionImpl.java:956)
at com.mysql.cj.jdbc.ConnectionImpl.createNewIO(ConnectionImpl.java:826)
... 6 more
Caused by: java.net.ConnectException: Connection refused: connect
at java.base/sun.nio.ch.Net.connect0(Native Method)
at java.base/sun.nio.ch.Net.connect(Net.java:503)
at java.base/sun.nio.ch.Net.connect(Net.java:492)
at java.base/sun.nio.ch.NioSocketImpl.connect(NioSocketImpl.java:588)
at java.base/java.net.SocksSocketImpl.connect(SocksSocketImpl.java:333)
at java.base/java.net.Socket.connect(Socket.java:648)
at com.mysql.cj.protocol.StandardSocketFactory.connect(StandardSocketFactory.java:155)
at com.mysql.cj.protocol.a.NativeSocketConnection.connect(NativeSocketConnection.java:65)
... 9 more
进程以退出代码 0 结束
知道出了什么问题吗？谢谢！