java发送邮件

以QQ邮箱为例

首先需要获取到授权码

eynrcqbilfuzbifd

1.邮件组成及授权码获取

在发送邮件之前我们需要获取发送邮件的授权码

登录QQ邮箱->账户->设置->开启IMAP/SMTP服务获取授权码哦

我这里已经开启了，在第一次开启或者关闭之后再次开启时，需要按照提示发送一个短信到指定的端口号上进行验证，验证通过才行获取授权码，获取到授权码之后保存好就可以了。

2.搭建一个SpringBoot工程

引入依赖

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

邮件配置

# 配置 smtp 服务器地址
spring.mail.host=smtp.qq.com
# smtp 服务器的端口
spring.mail.port=587
# 设置传输协议smtp
spring.mail.protocol=smtp
# 配置邮箱用户名
spring.mail.username=252539670@qq.com
# 配置申请到的授权码
spring.mail.password=eynrcqbilfuzbifd
# 配置邮件编码
spring.mail.default-encoding=UTF-8
# 配饰 SSL 加密工厂
spring.mail.properties.mail.smtp.socketFactoryClass=javax.net.ssl.SSLSocketFactory
# 表示开启 DEBUG 模式
spring.mail.properties.mail.debug=true

编写测试类

@SpringBootTest
class LlpJavamailApplicationTests {

        @Autowired
        JavaMailSender javaMailSender;

        /**
         *  发送简单邮件
         */
        @Test
        public void sendSimpleMail() {
            SimpleMailMessage msg = new SimpleMailMessage(); //构建一个邮件对象
            msg.setSubject("这是一封测试邮件"); // 设置邮件主题
            msg.setFrom("发件人邮箱"); // 设置邮箱发送者
            msg.setTo("收件人邮箱"); // 设置邮件接收者，可以有多个接收者,多个接收邮箱用逗号隔开
            msg.setSentDate(new Date());    // 设置邮件发送日期
            msg.setText("这是测试邮件的正文");   // 设置邮件的正文
            javaMailSender.send(msg);
        }

    /**
     *  发送带附件的邮件
     * @throws MessagingException
     */
    @Test
    public void sendAttachFileMail() throws Exception {
        MimeMessage mimeMessage = javaMailSender.createMimeMessage();
        MimeMessageHelper helper = new MimeMessageHelper(mimeMessage,true);
        helper.setSubject("hello msj 这是一封测试邮件");
        helper.setFrom("发件人邮箱");
        helper.setTo("收件人邮箱");
        helper.setSentDate(new Date());
        helper.setText("测试邮件");
        String fileUrl = "https://cdn.jsdelivr.net/gh/RayLin24/imgs/imgsimage-20220103201648553.png";
        File file = FileUtil.getNetUrl(fileUrl);
        helper.addAttachment(UUID.randomUUID().toString()+fileUrl.substring(fileUrl.lastIndexOf(".")),file);
        javaMailSender.send(mimeMessage);
    }

}

根据文件地址获取file对象

package com.llp.llpjavamail.util;

import lombok.extern.slf4j.Slf4j;
import org.springframework.stereotype.Component;

import javax.net.ssl.*;
import java.io.*;
import java.net.HttpURLConnection;
import java.net.URL;
import java.util.UUID;

@Slf4j
@Component
public class FileUtil {
    /**
     * 远程读取文件
     *
     * @param netUrl
     * @return
     */
    public static File getNetUrl(String netUrl) {
        //判断http和https
        File file = null;
        if (netUrl.startsWith("https://")) {
            file = getNetUrlHttps(netUrl);
        } else {
            file = getNetUrlHttp(netUrl);
        }
        return file;
    }

    public static File getNetUrlHttp(String fileUrl) {
        //对本地文件命名
        String fileName = UUID.randomUUID().toString()+fileUrl.substring(fileUrl.lastIndexOf("."));
        log.info("filename: =======================>"+fileName);
        File file = null;


        URL urlfile;
        InputStream inStream = null;
        OutputStream os = null;
        try {
            file = File.createTempFile("net_url", fileName);
            //下载
            urlfile = new URL(fileUrl);
            inStream = urlfile.openStream();
            os = new FileOutputStream(file);

            int bytesRead = 0;
            byte[] buffer = new byte[8192];
            while ((bytesRead = inStream.read(buffer, 0, 8192)) != -1) {
                os.write(buffer, 0, bytesRead);
            }
        } catch (Exception e) {
            log.error("远程图片获取错误："+fileUrl);
            e.printStackTrace();
        } finally {
            try {
                if (null != os) {
                    os.close();
                }
                if (null != inStream) {
                    inStream.close();
                }

            } catch (Exception e) {
                e.printStackTrace();
            }
        }

        return file;
    }

    /**
     * 下载文件到本地(支持https)
     *
     * @param fileUrl 远程地址
     * @throws Exception
     */

    public static File getNetUrlHttps(String fileUrl) {
        //对本地文件命名
        String fileName = UUID.randomUUID().toString()+fileUrl.substring(fileUrl.lastIndexOf("."));
        log.info("filename: =======================>"+fileName);
        File file = null;

        DataInputStream in = null;
        DataOutputStream out = null;
        try {
            file = File.createTempFile("net_url", fileName);

            SSLContext sslcontext = SSLContext.getInstance("SSL", "SunJSSE");
            sslcontext.init(null, new TrustManager[]{new X509TrustUtiil()}, new java.security.SecureRandom());
            URL url = new URL(fileUrl);
            HostnameVerifier ignoreHostnameVerifier = new HostnameVerifier() {
                @Override
                public boolean verify(String s, SSLSession sslsession) {
                    log.warn("WARNING: Hostname is not matched for cert.");
                    return true;
                }
            };
            HttpsURLConnection.setDefaultHostnameVerifier(ignoreHostnameVerifier);
            HttpsURLConnection.setDefaultSSLSocketFactory(sslcontext.getSocketFactory());
            HttpsURLConnection urlCon = (HttpsURLConnection) url.openConnection();
            urlCon.setConnectTimeout(6000);
            urlCon.setReadTimeout(6000);
            int code = urlCon.getResponseCode();
            if (code != HttpURLConnection.HTTP_OK) {
                throw new Exception("文件读取失败");
            }
            // 读文件流
            in = new DataInputStream(urlCon.getInputStream());
            out = new DataOutputStream(new FileOutputStream(file));
            byte[] buffer = new byte[2048];
            int count = 0;
            while ((count = in.read(buffer)) > 0) {
                out.write(buffer, 0, count);
            }
            out.close();
            in.close();
        } catch (Exception e) {
            log.error("远程图片获取错误："+fileUrl);
            e.printStackTrace();
        } finally {
            try {
                if (null != out) {
                    out.close();
                }
                if (null != in) {
                    in.close();
                }
            } catch (Exception e2) {
                e2.printStackTrace();
            }
        }

        return file;
    }
}

import javax.net.ssl.X509TrustManager;
import java.security.cert.CertificateException;
import java.security.cert.X509Certificate;
 
public class X509TrustUtiil implements X509TrustManager {
 
	@Override
	public void checkClientTrusted(X509Certificate[] arg0, String arg1) throws CertificateException {
		// TODO Auto-generated method stub
 
	}
 
	@Override
	public void checkServerTrusted(X509Certificate[] arg0, String arg1) throws CertificateException {
		// TODO Auto-generated method stub
 
	}
 
	@Override
	public X509Certificate[] getAcceptedIssuers() {
		// TODO Auto-generated method stub
		return null;
	}
 
}