从 localhost 使用 Spring Boot 发送电子邮件

Question

我想从本地主机（mac 或 linux）发送电子邮件到某个地方（假设是几个 gmail 地址）。只发邮件，从不收邮件，就像通知推送系统一样。

我知道 mac/linux 有一个“sendmail”程序，但现在我需要使用 spring boot 2.0 版发送电子邮件。

在我的 Mac 上： $ which sendmail /usr/sbin/sendmail

我在这里阅读了http://www.baeldung.com/spring-email 的spring boot 电子邮件教程，并在我的代码中进行了类似的配置，但它不起作用。在本教程中，mailsendr 的“主机”是“smtp.gmail.com”，在这种情况下，我需要“主机”是 localhost（我的 Spring Boot 应用程序将在其上运行的机器）。

这是我在 application.properties 中的电子邮件配置：

spring.mail.host=localhost
spring.mail.port=25
spring.mail.protocol=smtp
spring.mail.properties.mail.smtp.auth=false
spring.mail.properties.mail.smtp.starttls.enable=false
spring.mail.properties.mail.smtp.connectiontimeout=5000
spring.mail.properties.mail.smtp.timeout=3000
spring.mail.properties.mail.smtp.writetimeout=5000

当通过 JavaMailSender(autowired) 发送电子邮件时，spring boot 会抛出以下错误： org.springframework.mail.MailSendException: Mail server connection failed; nested exception is com.sun.mail.util.MailConnectException: Couldn't connect to host, port: localhost, 25; timeout 5000; nested exception is: java.net.ConnectException: Connection refused (Connection refused). Failed messages: com.sun.mail.util.MailConnectException: Couldn't connect to host, port: localhost, 25; timeout 5000; nested exception is: java.net.ConnectException: Connection refused (Connection refused) at org.springframework.mail.javamail.JavaMailSenderImpl.doSend(JavaMailSenderImpl.java:446) ~[spring-context-support-5.0.4.RELEASE.jar:5.0.4.RELEASE] at org.springframework.mail.javamail.JavaMailSenderImpl.send(JavaMailSenderImpl.java:321) ~[spring-context-support-5.0.4.RELEASE.jar:5.0.4.RELEASE] at org.springframework.mail.javamail.JavaMailSenderImpl.send(JavaMailSenderImpl.java:310) ~[spring-context-support-5.0.4.RELEASE.jar:5.0.4.RELEASE] at com.ibm.gem.service.EmailServiceImpl.sendSimpleMessage(EmailServiceImpl.java:33) ~[classes/:na] at com.ibm.gem.component.ApplicationStartup.onApplicationEvent(ApplicationStartup.java:39) [classes/:na] at com.ibm.gem.component.ApplicationStartup.onApplicationEvent(ApplicationStartup.java:1) [classes/:na] at org.springframework.context.event.SimpleApplicationEventMulticaster.doInvokeListener(SimpleApplicationEventMulticaster.java:172) [spring-context-5.0.4.RELEASE.jar:5.0.4.RELEASE] at org.springframework.context.event.SimpleApplicationEventMulticaster.invokeListener(SimpleApplicationEventMulticaster.java:165) [spring-context-5.0.4.RELEASE.jar:5.0.4.RELEASE] at org.springframework.context.event.SimpleApplicationEventMulticaster.multicastEvent(SimpleApplicationEventMulticaster.java:139) [spring-context-5.0.4.RELEASE.jar:5.0.4.RELEASE] at org.springframework.context.support.AbstractApplicationContext.publishEvent(AbstractApplicationContext.java:399) [spring-context-5.0.4.RELEASE.jar:5.0.4.RELEASE] at org.springframework.context.support.AbstractApplicationContext.publishEvent(AbstractApplicationContext.java:353) [spring-context-5.0.4.RELEASE.jar:5.0.4.RELEASE] at org.springframework.boot.context.event.EventPublishingRunListener.running(EventPublishingRunListener.java:103) [spring-boot-2.0.0.RELEASE.jar:2.0.0.RELEASE] at org.springframework.boot.SpringApplicationRunListeners.running(SpringApplicationRunListeners.java:78) [spring-boot-2.0.0.RELEASE.jar:2.0.0.RELEASE] at org.springframework.boot.SpringApplication.run(SpringApplication.java:341) [spring-boot-2.0.0.RELEASE.jar:2.0.0.RELEASE] at org.springframework.boot.SpringApplication.run(SpringApplication.java:1246) [spring-boot-2.0.0.RELEASE.jar:2.0.0.RELEASE] at org.springframework.boot.SpringApplication.run(SpringApplication.java:1234) [spring-boot-2.0.0.RELEASE.jar:2.0.0.RELEASE] at com.ibm.gem.PerfInsightApplication.main(PerfInsightApplication.java:11) [classes/:na] at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) ~[na:1.8.0_151] at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62) ~[na:1.8.0_151] at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) ~[na:1.8.0_151] at java.lang.reflect.Method.invoke(Method.java:498) ~[na:1.8.0_151] at org.springframework.boot.devtools.restart.RestartLauncher.run(RestartLauncher.java:49) [spring-boot-devtools-2.0.0.RELEASE.jar:2.0.0.RELEASE] Caused by: com.sun.mail.util.MailConnectException: Couldn't connect to host, port: localhost, 25; timeout 5000 at com.sun.mail.smtp.SMTPTransport.openServer(SMTPTransport.java:2209) ~[javax.mail-1.6.1.jar:1.6.1] at com.sun.mail.smtp.SMTPTransport.protocolConnect(SMTPTransport.java:740) ~[javax.mail-1.6.1.jar:1.6.1] at javax.mail.Service.connect(Service.java:366) ~[javax.mail-1.6.1.jar:1.6.1] at org.springframework.mail.javamail.JavaMailSenderImpl.connectTransport(JavaMailSenderImpl.java:515) ~[spring-context-support-5.0.4.RELEASE.jar:5.0.4.RELEASE] at org.springframework.mail.javamail.JavaMailSenderImpl.doSend(JavaMailSenderImpl.java:435) ~[spring-context-support-5.0.4.RELEASE.jar:5.0.4.RELEASE] ... 21 common frames omitted Caused by: java.net.ConnectException: Connection refused (Connection refused) at java.net.PlainSocketImpl.socketConnect(Native Method) ~[na:1.8.0_151] at java.net.AbstractPlainSocketImpl.doConnect(AbstractPlainSocketImpl.java:350) ~[na:1.8.0_151] at java.net.AbstractPlainSocketImpl.connectToAddress(AbstractPlainSocketImpl.java:206) ~[na:1.8.0_151] at java.net.AbstractPlainSocketImpl.connect(AbstractPlainSocketImpl.java:188) ~[na:1.8.0_151] at java.net.SocksSocketImpl.connect(SocksSocketImpl.java:392) ~[na:1.8.0_151] at java.net.Socket.connect(Socket.java:589) ~[na:1.8.0_151] at com.sun.mail.util.WriteTimeoutSocket.connect(WriteTimeoutSocket.java:115) ~[javax.mail-1.6.1.jar:1.6.1] at com.sun.mail.util.SocketFetcher.createSocket(SocketFetcher.java:351) ~[javax.mail-1.6.1.jar:1.6.1] at com.sun.mail.util.SocketFetcher.getSocket(SocketFetcher.java:239) ~[javax.mail-1.6.1.jar:1.6.1] at com.sun.mail.smtp.SMTPTransport.openServer(SMTPTransport.java:2175) ~[javax.mail-1.6.1.jar:1.6.1] ... 25 common frames omitted

我认为我在 application.properties 中的配置是错误的，但我不知道正确的配置是什么。 mac/linux 没有内置的 smtp 服务器，是吗？我不知道，我不想安装一个。我只想要类似“sendmail”程序的功能。使用“sendmail”程序时，不需要指定协议、端口、ssl等参数，不知道为什么我在使用spring boot的时候要提供这些信息，也不知道怎么办在我的电脑上找到这些信息。

谁能帮帮我？

提前致谢。

Answer 1

问题解决了。

原来 mac（以及我相信的大多数 linux 系统）都预装了邮件系统postfix。在使用 spring boot 发送电子邮件之前，您需要启动邮件系统（包括一个 smtp 服务器）。

使用以下命令启动和检查后缀状态： $ sudo postfix status $ sudo postfix start

在 mac 上，我使用以下命令检查 smtp 是否正在运行： $ sudo lsof -i :smtp COMMAND PID USER FD TYPE DEVICE SIZE/OFF NODE NAME master 84359 root 13u IPv4 0xacc57a372acc10b 0t0 TCP localhost:smtp (LISTEN) master 84359 root 14u IPv6 0xacc57a379b3eb63 0t0 TCP localhost:smtp (LISTEN) postscree 84562 _postfix 6u IPv4 0xacc57a372acc10b 0t0 TCP localhost:smtp (LISTEN) postscree 84562 _postfix 7u IPv6 0xacc57a379b3eb63 0t0 TCP localhost:smtp (LISTEN)

而在spring boot application.properties中，我只需要一行配置： spring.mail.host=localhost

成功了！