发送带图片及附件的邮件

核心代码：

package com.gongyi;import com.sun.mail.util.MailSSLSocketFactory;import javax.activation.DataHandler;
import javax.activation.FileDataSource;
import javax.mail.*;
import javax.mail.internet.InternetAddress;
import javax.mail.internet.MimeBodyPart;
import javax.mail.internet.MimeMessage;
import javax.mail.internet.MimeMultipart;
import java.util.Properties;//发送一封带图片的邮件
public class MailDemo02 {public static void main(String[] args) throws Exception {Properties prop = new Properties();prop.setProperty("mail.host", "smtp.qq.com");//设置QQ邮箱服务器prop.setProperty("mail.transport.protocol", "smtp");//邮件发送协议prop.setProperty("mail.smtp.auth", "true");//需要验证用户名和密码//关于QQ邮箱，还要设置SSL加密，加上以下代码即可，大厂,其他邮箱不需要MailSSLSocketFactory sf = new MailSSLSocketFactory();sf.setTrustAllHosts(true);prop.put("mail.smtp.ssl.enable", "true");prop.put("mail.smtp.ssl.socketFactory", sf);//使用JavaMail发送邮件的5个步骤//1.创建定义整个应用程序所需的环境信息的Session对象//QQ才有，其他邮箱就不用Session session = Session.getDefaultInstance(prop, new Authenticator() {@Overrideprotected PasswordAuthentication getPasswordAuthentication() {//发件人邮件用户名，授权码return new PasswordAuthentication("1072805311@qq.com", "sdfsdf");}});//开启session的debug模式，这样就可以查看程序发送Email的运行状态session.setDebug(true);//2.通过Session得到transport对象Transport ts = session.getTransport();//3.使用邮箱的用户名和授权码连上邮件服务器ts.connect("smtp.qq.com", "1072805311@qq.com", "sdfsdf");//4.创建邮件:写邮件//注意：需要传递sessionMimeMessage message = new MimeMessage(session);//指明邮件的发件人message.setFrom(new InternetAddress("1072805311@qq.com"));//指明邮件的收件人，现在发件人和收件人是一样的，那就是自己给自己发message.setRecipient(Message.RecipientType.TO, new InternetAddress("15518987725@163.com"));//邮件的标题message.setSubject("欢迎来到工一说Java");//===============================================================//准备图片数据MimeBodyPart image = new MimeBodyPart();//图片需要经过数据处理... DataHandler：数据处理DataHandler dh = new DataHandler(new FileDataSource("C:\\Users\\Administrator\\Desktop\\学习笔记\\javaweb\\codes\\功能扩展\\mail-java\\src\\1.jpg"));image.setDataHandler(dh);//在我们的body中放入这个处理的图片数据image.setContentID("bz.jpg");//给图片设置一个ID，我们在后面可以使用//准备正文数据MimeBodyPart text = new MimeBodyPart();text.setContent("这是一封邮件正文带图片<img src='cid:bz.jpg'>的附件", "text/html;charset=UTF-8 ");//描述数据关系MimeMultipart mm = new MimeMultipart();mm.addBodyPart(image);mm.addBodyPart(text);mm.setSubType("related");//设置到消息中，保存修改message.setContent(mm);//把最后编辑好的邮件放到消息当中message.saveChanges();//保存修改//===============================================================//5.发送邮件ts.sendMessage(message, message.getAllRecipients());//6.关闭连接ts.close();}}

邮箱注册后发送邮件

1.在empty工程下新建子module

2.普通maven工程（不用模板）

3.添加web支持

4.配置tomcat

核心代码：

pojo/User.java

package com.gongyi.pojo;import java.io.Serializable;public class User implements Serializable {private String username;private String password;private String email;public User() {}public User(String username, String password, String email) {this.username = username;this.password = password;this.email = email;}public String getUsername() {return username;}public void setUsername(String username) {this.username = username;}public String getPassword() {return password;}public void setPassword(String password) {this.password = password;}public String getEmail() {return email;}public void setEmail(String email) {this.email = email;}@Override//方便调试public String toString() {return "User{" +"username='" + username + '\'' +", password='" + password + '\'' +", email='" + email + '\'' +'}';}
}

pojo/User1.java

package com.gongyi.pojo;import lombok.AllArgsConstructor;
import lombok.Data;
import lombok.NoArgsConstructor;@Data
@AllArgsConstructor
@NoArgsConstructor
public class User1 {private String username;private String password;private String email;}

utils/SendEmail.java

package com.gongyi.utils;import com.gongyi.pojo.User;
import com.sun.mail.util.MailSSLSocketFactory;import javax.mail.*;
import javax.mail.internet.InternetAddress;
import javax.mail.internet.MimeMessage;
import java.util.Properties;//网站三秒原则：用户体验
//多线程实现用户体验！（异步处理）
public class SendEmail extends Thread {//用于给用户发送邮件的邮箱private String from = "1072805311@qq.com";//邮箱的用户名private String username = "1072805311@qq.com";//邮箱的密码private String password = "sdfsdf";//发送邮件的服务器地址private String host = "smtp.qq.com";private User user;public SendEmail(User user) {this.user = user;}//重写run方法的实现，在run方法中发送邮件给指定用户@Overridepublic void run() {try {Properties prop = new Properties();prop.setProperty("mail.host", host);prop.setProperty("mail.transport.protocol", "smtp");prop.setProperty("mail.smtp.auth", "true");//关于QQ邮箱，还要设置SSL加密，加上以下代码即可MailSSLSocketFactory sf = new MailSSLSocketFactory();sf.setTrustAllHosts(true);prop.put("mail.smtp.ssl.enable", "true");prop.put("mail.smtp.ssl.socketFactory", sf);//1.创建定义整个应用程序所需的环境信息的Session对象Session session = Session.getDefaultInstance(prop, new Authenticator() {@Overrideprotected PasswordAuthentication getPasswordAuthentication() {//发件人邮件用户名，授权码return new PasswordAuthentication("1072805311@qq.com", "sdfsd");}});//开启session的debug模式，这样就可以查看程序发送Email的运行状态session.setDebug(true);//2.通过Session得到transport对象Transport ts = session.getTransport();//3.使用邮箱的用户名和授权码连上邮件服务器ts.connect(host, username, password);//4.创建邮件:写邮件MimeMessage message = new MimeMessage(session);message.setFrom(new InternetAddress(from));//发件人message.setRecipient(Message.RecipientType.TO, new InternetAddress(user.getEmail()));//收件人message.setSubject("用户注册邮件");//邮件的标题String info = "恭喜您注册成功，您的用户名：" + user.getUsername() + ",您的密码：" + user.getPassword() + "，请妥善保管，如有问题，请联系网站客服";message.setContent(info, "text/html;charset=UTF-8");message.saveChanges();//5.发送邮件ts.sendMessage(message, message.getAllRecipients());//6.关闭连接ts.close();} catch (Exception e) {e.printStackTrace();}}
}

servlet/RegisterServlet.java

package com.gongyi.servlet;import com.gongyi.pojo.User;
import com.gongyi.utils.SendEmail;import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;public class RegisterServlet extends HttpServlet {@Overrideprotected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {req.setCharacterEncoding("UTF-8");resp.setCharacterEncoding("UTF-8");//接收用户请求，封装对象String username = req.getParameter("username");String password = req.getParameter("password");String email = req.getParameter("email");User user = new User(username, password, email);//用户注册成功之后，给用户发送一封邮件//我们使用线程来专门发送邮件，防止出现耗时，和网站注册人数过多的情况SendEmail send = new SendEmail(user);//启动线程，线程启动之后，就会执行run()方法来发送邮件send.start();//send.run();//换成run体验注册时用户体验问题//注册用户req.setAttribute("message", "注册成功了，我们已经发了一封带了注册信息的电子邮件，请查收！如网络不稳定，可能过会儿才能收到！");req.getRequestDispatcher("info.jsp").forward(req, resp);}@Overrideprotected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {doGet(req, resp);}
}

web.xml

<?xml version="1.0" encoding="UTF-8"?>
<web-app xmlns="http://xmlns.jcp.org/xml/ns/javaee"xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"xsi:schemaLocation="http://xmlns.jcp.org/xml/ns/javaee http://xmlns.jcp.org/xml/ns/javaee/web-app_4_0.xsd"version="4.0"><servlet><servlet-name>RegisterServlet</servlet-name><servlet-class>com.gongyi.servlet.RegisterServlet</servlet-class></servlet><servlet-mapping><servlet-name>RegisterServlet</servlet-name><url-pattern>/RegisterServlet.do</url-pattern></servlet-mapping>
</web-app>

index.jsp

<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<html><head><title>注册</title></head><body><form action="${pageContext.request.contextPath}/RegisterServlet.do" method="post">用户名：<input type="text" name="username"><br/>密码：<input type="password" name="password"><br/>邮箱：<input type="text" name="email"><br/><input type="submit" value="注册"></form></body>
</html>

info.jsp

<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<html><head><title>Title</title></head><body><h1>xxx网站温馨提示：</h1>${message}</body>
</html>

pom.xml

<?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 http://maven.apache.org/xsd/maven-4.0.0.xsd"><modelVersion>4.0.0</modelVersion><groupId>com.gongyi</groupId><artifactId>WebMail</artifactId><version>1.0-SNAPSHOT</version><packaging>war</packaging><dependencies><dependency><groupId>javax.servlet</groupId><artifactId>javax.servlet-api</artifactId><version>3.1.0</version></dependency><dependency><groupId>org.projectlombok</groupId><artifactId>lombok</artifactId><version>1.16.10</version></dependency></dependencies></project>

springboot搭建项目发送邮件【更快，更简单开发，底层做了好多封装，需要了解底层原理】

删除无用目录：

虽然就直接引入了两个包，但是间接依赖的包很多

代码结构：

核心代码：

DemoApplication.java

package com.example.demo;import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;@SpringBootApplication
public class DemoApplication {public static void main(String[] args) {SpringApplication.run(DemoApplication.class, args);}}

application.properties

server.port=8081
spring.mail.username=1072805311@qq.com
spring.mail.password=sdfsdfdsf
spring.mail.host=smtp.qq.com
spring.mail.properties.mail.smtp.ssl.enable=true

DemoApplicationTests.java

package com.example.demo;import org.junit.jupiter.api.Test;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.test.context.SpringBootTest;
import org.springframework.mail.SimpleMailMessage;
import org.springframework.mail.javamail.JavaMailSenderImpl;
import org.springframework.mail.javamail.MimeMessageHelper;import javax.mail.internet.MimeMessage;
import java.io.File;@SpringBootTest
class DemoApplicationTests {@AutowiredJavaMailSenderImpl mailSender;@Testvoid contextLoads() {//发送邮件//收件人//内容SimpleMailMessage message = new SimpleMailMessage();message.setSubject("工一说Java");message.setText("Hello World");message.setFrom("1072805311@qq.com");message.setTo("1072805311@qq.com");mailSender.send(message);}@Testvoid test2() throws Exception {MimeMessage mimeMessage = mailSender.createMimeMessage();MimeMessageHelper helper = new MimeMessageHelper(mimeMessage, true);helper.setSubject("工一说Java");helper.setText("<h1>Hello,World</h1>", true);//附件helper.addAttachment("1.jpg", new File("C:\\Users\\Administrator\\Desktop\\学习笔记\\javaweb\\codes\\demo\\src\\main\\resources\\1.jpg"));helper.addAttachment("2.jpg", new File("C:\\Users\\Administrator\\Desktop\\学习笔记\\javaweb\\codes\\demo\\src\\main\\resources\\2.jpg"));helper.addAttachment("3.jpg", new File("C:\\Users\\Administrator\\Desktop\\学习笔记\\javaweb\\codes\\demo\\src\\main\\resources\\3.jpg"));helper.addAttachment("4.jpg", new File("C:\\Users\\Administrator\\Desktop\\学习笔记\\javaweb\\codes\\demo\\src\\main\\resources\\4.jpg"));helper.setFrom("1072805311@qq.com");helper.setTo("1072805311@qq.com");mailSender.send(mimeMessage);}}

pom.xml

<?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>2.5.6</version><relativePath/> <!-- lookup parent from repository --></parent><groupId>com.example</groupId><artifactId>demo</artifactId><version>0.0.1-SNAPSHOT</version><name>demo</name><description>Demo project for Spring Boot</description><properties><java.version>1.8</java.version></properties><dependencies><dependency><groupId>org.springframework.boot</groupId><artifactId>spring-boot-starter</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></plugin></plugins></build></project>

效果图：

彩蛋

1.发送附件，fileName设置为中文乱码

参考

老代码：

 attach.setFileName("附件.jpg");//附件和正文图片的区别是需要设置fileName

新代码：

attach.setFileName(MimeUtility.encodeText("附件.jpg"));//附件和正文图片的区别是需要设置fileName

效果图：

2.maven工程快速导包

3.脚手架

是一个基本框架，是成型的，可以不断添加小功能【扩展】

4.lombok

5.普通maven工程不通过修改pom文件也可以实现导包效果

6.web服务发布后将依赖包放入到lib下

7…start()是多线程方法，.run()是普通方法

8.注册信息时发送邮件遇到问题

1）java.lang.ClassNotFoundException: javax.mail.Authenticator

发现target目录下无web资源及相关依赖包

无 WEB-INF是因为，pom文件中的无【对比了正常的web项目看出来的】

<packaging>war</packaging>

加上就行，默认是jar包

启动后，首页404，看输出的文件也无index.jsp

修复这里就行

改成如下就行：【是因为这不是一个标准的web工程，是普通maven工程添加了web支持】

2）邮箱收到中文乱码：

debug发现前端传过来就乱码了：

解决：

在 RegisterServlet.java中加入如下代码：

req.setCharacterEncoding("UTF-8");
resp.setCharacterEncoding("UTF-8");

9.阿里特别注重底层

看《深入JVM》

10.springboot的spring-boot-starter-mail底层还是javamail