---
title: 'Java mail'
disqus: hackmd
---
###### tags: `SpringBoot` `email`
Java mail
===

[TOC]

## 筆記目的

讓人可以透過spring boot去寄送email
當然常用的大概會有以下幾種，但本文就以最簡單的幾種作為範例

* [參考自spring mail筆記](https://sites.google.com/im.fju.edu.tw/web/spring-framework-web/spring-mail#h.p_0sRi8gR978a1)

## 程式碼部分

### 專案架構

請忽略TestMail這個java檔案

### pom.xml

<dependency>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-mail</artifactId>
</dependency>

<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0"
	xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
	xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 https://maven.apache.org/xsd/maven-4.0.0.xsd">
	<modelVersion>4.0.0</modelVersion>
	<parent>
		<groupId>org.springframework.boot</groupId>
		<artifactId>spring-boot-starter-parent</artifactId>
		<version>2.5.3</version>
		<relativePath /> <!-- lookup parent from repository -->
	</parent>
	<groupId>com.example</groupId>
	<artifactId>helloworld</artifactId>
	<version>0.0.1-SNAPSHOT</version>
	<name>helloworld</name>
	<description>Demo project for Spring Boot</description>
	<properties>
		<java.version>8</java.version>
	</properties>
	<dependencies>
		<dependency>
			<groupId>org.springframework.boot</groupId>
			<artifactId>spring-boot-starter-web</artifactId>
		</dependency>
		<dependency>
			<groupId>org.springframework.boot</groupId>
			<artifactId>spring-boot-starter-mail</artifactId>
		</dependency>


		<dependency>
			<groupId>org.springframework.boot</groupId>
			<artifactId>spring-boot-starter-test</artifactId>
			<scope>test</scope>
		</dependency>
	</dependencies>

	<build>
		<plugins>
			<plugin>
				<groupId>org.springframework.boot</groupId>
				<artifactId>spring-boot-maven-plugin</artifactId>
				<configuration>
					<excludes>
						<exclude>
							<groupId>org.projectlombok</groupId>
							<artifactId>lombok</artifactId>
						</exclude>
					</excludes>
				</configuration>
			</plugin>
		</plugins>
	</build>

</project>

### application.properties

spring.mail.host = smtp.gmail.com
spring.mail.username = [e-mail]
spring.mail.password = xxxx
send.from.email= [e-mail]
spring.mail.properties.mail.smtp.auth = true;
spring.mail.properties.mail.smtp.starttls.enable = true
spring.mail.properties.mail.smtp.ssl.enable = true
spring.mail.properties.mail.socketFactory.port=587
spring.mail.properties.mail.socketFactory.class=javax.net.ssl.SSLSocketFactory
spring.mail.properties.mail.socketFactory.fallback=false
spring.mail.smtp.port= 587

### Controller

package com.example.demo.controller;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.ResponseBody;

import com.example.demo.service.MailService;

@Controller
public class MailController {
  @Autowired
 private MailService mailService;
 
 @GetMapping("/")
 @ResponseBody
 public String hello(){
  mailService.prepareAndSend("emailyouwanttosend","Sample email from XXX");
  return "Mail sent";
 }

}

> 把emailyouwanttosend替換成你收信人的信箱
把Sample email from XXX替換成你要寄信的訊息

### Service

package com.example.demo.service;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.mail.MailException;
import org.springframework.mail.javamail.JavaMailSender;
import org.springframework.mail.javamail.MimeMessageHelper;
import org.springframework.mail.javamail.MimeMessagePreparator;
import org.springframework.stereotype.Service;

@Service
public class MailService {
 
    private JavaMailSender mailSender;
 
    @Autowired
    public MailService(JavaMailSender mailSender) {
        this.mailSender = mailSender;
    }
 
    public void prepareAndSend(String recipient, String message) {
       MimeMessagePreparator messagePreparator = mimeMessage -> {
             MimeMessageHelper messageHelper = new MimeMessageHelper(mimeMessage);
             messageHelper.setFrom("[e-mail]");
             messageHelper.setTo(recipient);
             messageHelper.setSubject(message);
             messageHelper.setText(message);
         };
         try {
             mailSender.send(messagePreparator);
             //System.out.println("sent");
         } catch (MailException e) {
             //System.out.println(e);
             // runtime exception; compiler will not force you to handle it
         }
    }
 
}

### JavaMailApplication(對這個class按下執行，因為他有main函數)

package com.example.demo;

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;

@SpringBootApplication
public class JavaMailApplication {

	public static void main(String[] args) {
		SpringApplication.run(JavaMailApplication.class, args);
	}

}

> 之後在瀏覽器瀏覽
> http://localhost:8080/
>
> 會出現以下文字 Mail sent


會出現**Mail sent**也是因為在Controller當中我們有以下的程式碼片段

@GetMapping("/")
 @ResponseBody
 public String hello(){
  mailService.prepareAndSend("emailyouwanttosend","Sample email from XXX");
  return "Mail sent";
 }