我正在从事研究项目。现在我正处于将项目移动到 docker 容器的阶段。我在我的网站上放置了 tomcat，在数据库中放置了 mysql docker-compose.yml。不幸的是，来自 tomcat 的类无法连接数据库
Java代码
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
public class Waliduj {
String url="jdbc:mysql://localhost:3306/uczelnia?useTimezone=true&serverTimezone=UTC";
String username="root";
String password="121212";
public boolean Waliduje(String uname,String pass) {
try {
Class.forName("com.mysql.jdbc.Driver");
Connection con = DriverManager.getConnection(url,username,password);
PreparedStatement st=con.prepareStatement("SELECT email,haslo FROM logowanie WHERE email=? AND haslo=?");
st.setString(1,uname);
st.setString(2,pass);
ResultSet rs = st.executeQuery();
if(rs.next()) {
return true;
}
} catch (SQLException e) {
e.printStackTrace();
} catch (ClassNotFoundException se) {
// TODO Auto-generated catch block
se.printStackTrace();
}
return false;
}
}
Docker文件代码
FROM tomcat:8.0.41-jre8
COPY ./webapp /usr/local/tomcat/webapps/webapp
CMD ["catalina.sh", "run"]
docker-compose.yml代码
version: '3'
services:
web:
build: .
ports:
- "8080:8080"
links:
- "db:uczelnia"
db:
image: mysql
environment:
MYSQL_ROOT_PASSWORD: 121212
MYSQL_DATABASE: uczelnia
ports:
- "3306:3306"
PhpMyAdmin:
image: nazarpc/phpmyadmin
ports:
- "8090:80"
links:
- db:mysql
错误代码
web_1 | com.mysql.cj.jdbc.exceptions.CommunicationsException: Communications link failure
web_1 |
web_1 | The last packet sent successfully to the server was 0 milliseconds ago. The driver has not received any packets from the server.
web_1 | at com.mysql.cj.jdbc.exceptions.SQLError.createCommunicationsException(SQLError.java:172)
web_1 | at com.mysql.cj.jdbc.exceptions.SQLExceptionsMapping.translateException(SQLExceptionsMapping.java:64)
web_1 | at com.mysql.cj.jdbc.ConnectionImpl.createNewIO(ConnectionImpl.java:862)
web_1 | at com.mysql.cj.jdbc.ConnectionImpl.<init>(ConnectionImpl.java:444)
web_1 | at com.mysql.cj.jdbc.ConnectionImpl.getInstance(ConnectionImpl.java:230)
web_1 | at com.mysql.cj.jdbc.NonRegisteringDriver.connect(NonRegisteringDriver.java:226)
web_1 | at java.sql.DriverManager.getConnection(DriverManager.java:664)
web_1 | at java.sql.DriverManager.getConnection(DriverManager.java:247)
web_1 | at com.login.walidacja.Waliduj.Waliduje(Waliduj.java:20)
web_1 | at com.login.Login.doPost(Login.java:27)
web_1 | at javax.servlet.http.HttpServlet.service(HttpServlet.java:648)
web_1 | at javax.servlet.http.HttpServlet.service(HttpServlet.java:729)
web_1 | at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:292)
web_1 | at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:207)
web_1 | at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52)
web_1 | at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:240)
web_1 | at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:207)
web_1 | at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:212)
web_1 | at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:94)
web_1 | at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:504)
web_1 | at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:141)
web_1 | at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:79)
web_1 | at org.apache.catalina.valves.AbstractAccessLogValve.invoke(AbstractAccessLogValve.java:620)
web_1 | at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:88)
web_1 | at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:509)
web_1 | at org.apache.coyote.http11.AbstractHttp11Processor.process(AbstractHttp11Processor.java:1104)
web_1 | at org.apache.coyote.AbstractProtocol$AbstractConnectionHandler.process(AbstractProtocol.java:684)
web_1 | at org.apache.tomcat.util.net.AprEndpoint$SocketProcessor.doRun(AprEndpoint.java:2508)
web_1 | at org.apache.tomcat.util.net.AprEndpoint$SocketProcessor.run(AprEndpoint.java:2497)
web_1 | at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142)
web_1 | at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)
web_1 | at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61)
web_1 | at java.lang.Thread.run(Thread.java:745)
web_1 | Caused by: com.mysql.cj.exceptions.CJCommunicationsException: Communications link failure
web_1 |
web_1 | The last packet sent successfully to the server was 0 milliseconds ago. The driver has not received any packets from the server.
web_1 | at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
web_1 | at sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:62)
web_1 | at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45)
web_1 | at java.lang.reflect.Constructor.newInstance(Constructor.java:423)
web_1 | at com.mysql.cj.exceptions.ExceptionFactory.createException(ExceptionFactory.java:59)
web_1 | at com.mysql.cj.exceptions.ExceptionFactory.createException(ExceptionFactory.java:103)
web_1 | at com.mysql.cj.exceptions.ExceptionFactory.createException(ExceptionFactory.java:149)
web_1 | at com.mysql.cj.exceptions.ExceptionFactory.createCommunicationsException(ExceptionFactory.java:165)
web_1 | at com.mysql.cj.protocol.a.NativeSocketConnection.connect(NativeSocketConnection.java:92)
web_1 | at com.mysql.cj.NativeSession.connect(NativeSession.java:152)
web_1 | at com.mysql.cj.jdbc.ConnectionImpl.connectOneTryOnly(ConnectionImpl.java:982)
web_1 | at com.mysql.cj.jdbc.ConnectionImpl.createNewIO(ConnectionImpl.java:852)
web_1 | ... 30 more
web_1 | Caused by: java.net.ConnectException: Connection refused (Connection refused)
web_1 | at java.net.PlainSocketImpl.socketConnect(Native Method)
web_1 | at java.net.AbstractPlainSocketImpl.doConnect(AbstractPlainSocketImpl.java:350)
web_1 | at java.net.AbstractPlainSocketImpl.connectToAddress(AbstractPlainSocketImpl.java:206)
web_1 | at java.net.AbstractPlainSocketImpl.connect(AbstractPlainSocketImpl.java:188)
web_1 | at java.net.SocksSocketImpl.connect(SocksSocketImpl.java:392)
web_1 | at java.net.Socket.connect(Socket.java:589)
web_1 | at com.mysql.cj.protocol.StandardSocketFactory.connect(StandardSocketFactory.java:173)
web_1 | at com.mysql.cj.protocol.a.NativeSocketConnection.connect(NativeSocketConnection.java:66)
web_1 | ... 33 more
附加信息:
- 我在 Windows 10 上工作，所以 docker 也在 Windows 上。
- 我为拼写错误道歉，但我来自波兰，所以英语不是 我的
最佳答案
通过组合文件，您的数据库服务将通过 db 在网络上被引用。 links 关键字不是必需的，除非您只需要为您的容器起一个不同的名称。如果您更改 Java 代码以连接到 jdbc:mysql://db:3306/uczelnia?useTimezone=true&serverTimezone=UTC，它应该会按预期工作。
关于java - 在docker-compose中连接tomcat和mysql，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/52011016/