报错内容

Exception in thread "main" javax.mail.MessagingException: Could not connect to SMTP host: smtp.163.com, port: 465, response: -1at com.sun.mail.smtp.SMTPTransport.openServer(SMTPTransport.java:1949)at com.sun.mail.smtp.SMTPTransport.protocolConnect(SMTPTransport.java:654)at javax.mail.Service.connect(Service.java:317)at javax.mail.Service.connect(Service.java:176)at javax.mail.Service.connect(Service.java:125)at javax.mail.Transport.send0(Transport.java:194)at javax.mail.Transport.send(Transport.java:124)

package com.liang.reggie.utils;import javax.mail.*;
import javax.mail.internet.InternetAddress;
import javax.mail.internet.MimeMessage;
import javax.mail.internet.MimeMessage.RecipientType;
import java.util.Arrays;
import java.util.Collections;
import java.util.List;
import java.util.Properties;public class MailUtils {public static void main(String[] args) throws MessagingException {//可以在这里直接测试方法，填自己的邮箱即可sendTestMail("**8@qq.com", new MailUtils().achieveCode());}public static void sendTestMail(String email, String code) throws MessagingException {// 创建Properties 类用于记录邮箱的一些属性Properties props = new Properties();// 表示SMTP发送邮件，必须进行身份验证props.put("mail.smtp.auth", "true");//此处填写SMTP服务器props.put("mail.smtp.host", "smtp.163.com");//端口号，163邮箱服务器地址端口465props.put("mail.smtp.port", "465");// 此处填写，写信人的账号props.put("mail.user", "**@163.com");// 此处填写16位STMP口令props.put("mail.password", "**");props.put("mail.smtp.ssl.enable", true);// 构建授权信息，用于进行SMTP进行身份验证Authenticator authenticator = new Authenticator() {protected PasswordAuthentication getPasswordAuthentication() {// 用户名、密码String userName = props.getProperty("mail.user");String password = props.getProperty("mail.password");return new PasswordAuthentication(userName, password);}};// 使用环境属性和授权信息，创建邮件会话Session mailSession = Session.getInstance(props, authenticator);// 创建邮件消息MimeMessage message = new MimeMessage(mailSession);// 设置发件人InternetAddress form = new InternetAddress(props.getProperty("mail.user"));message.setFrom(form);// 设置收件人的邮箱InternetAddress to = new InternetAddress(email);message.setRecipient(RecipientType.TO, to);// 设置邮件标题message.setSubject("Kyle's Blog 邮件测试");// 设置邮件的内容体message.setContent("尊敬的用户:你好!\n注册验证码为:" + code + "(有效期为一分钟,请勿告知他人)", "text/html;charset=UTF-8");// 最后当然就是发送邮件啦Transport.send(message);}public static String achieveCode() {  //由于数字 1 、 0 和字母 O 、l 有时分不清楚，所以，没有数字 1 、 0String[] beforeShuffle = new String[]{"2", "3", "4", "5", "6", "7", "8", "9", "A", "B", "C", "D", "E", "F","G", "H", "I", "J", "K", "L", "M", "N", "O", "P", "Q", "R", "S", "T", "U", "V", "W", "X", "Y", "Z", "a","b", "c", "d", "e", "f", "g", "h", "i", "j", "k", "l", "m", "n", "o", "p", "q", "r", "s", "t", "u", "v","w", "x", "y", "z"};List<String> list = Arrays.asList(beforeShuffle);//将数组转换为集合Collections.shuffle(list);  //打乱集合顺序StringBuilder sb = new StringBuilder();for (String s : list) {sb.append(s); //将集合转化为字符串}return sb.substring(3, 8);}
}

其实代码没啥问题，主要就是两个步骤

第一个，增加

props.put("mail.smtp.ssl.enable", true); 

如果没有这个代码块，那就请加上这个，因为这个是启用SMTP服务器的SSL加密连接。
网上到这就好了，但是我的代码还是报错，所以又有了第二步

第二步

打开目录
C:\Program Files\Java\jdk-17.0.5\conf\security

修改java.security：不要SSL3,TLSv1, TLSv1.1

dk.tls.disabledAlgorithms=MD5, SSLv3, DSA, RSA keySize < 2048
jdk.tls.disabledAlgorithms=RC4, DES, MD5withRSA, \DH keySize < 1024, EC keySize < 224, 3DES_EDE_CBC, anon, NULL, \include jdk.disabled.namedCurves