一些微服务项目开发中遇到的问题

如何理解SpringCloud中常用组件之间的配合使用？

使用SpringCloud Gateway时，无法使用Spring Session

1. spring cloud gateway是基于webflux，是非阻塞的，zuul是基于servlet的，是阻塞的，所以在gateway中需要将EnableRedisHttpSession注解换成EnableRedisWebSession：

   @EnableRedisWebSession(saveMode = SaveMode.ALWAYS)
   @Configuration
   public class RedisSessionConfig {
       @Bean
       public WebSessionIdResolver webSessionIdResolver() {
           return new CustomWebSessionIdResolver();
       }
   
   }
   class CustomWebSessionIdResolver extends CookieWebSessionIdResolver {
       // 重写resolve方法 对SESSION进行base64解码
       @Override
       public List<String> resolveSessionIds(ServerWebExchange exchange) {
           MultiValueMap<String, HttpCookie> cookieMap = exchange.getRequest().getCookies();
           // 获取SESSION
           List<HttpCookie> cookies = cookieMap.get(getCookieName());
           if (cookies == null) {
               return Collections.emptyList();
           }
           return cookies.stream().map(HttpCookie::getValue).map(this::base64Decode).collect(Collectors.toList());
       }
   
       private String base64Decode(String base64Value) {
           try {
               byte[] decodedCookieBytes = Base64.getDecoder().decode(base64Value);
               return new String(decodedCookieBytes);
           } catch (Exception ex) {
               return null;
           }
       }
   }

2. 实现GlobalFilter接口，例如：登录过滤功能

   @Component
   public class SCWAccessFilter implements GlobalFilter, Ordered {
   
       @Override
       public Mono<Void> filter(ServerWebExchange exchange, GatewayFilterChain chain) {
           ServerHttpRequest request = exchange.getRequest();
           String path = request.getPath().toString();
           if (AccessPassResources.PASS_RES_SET.contains(path)) {
               return chain.filter(exchange);
           }
           if (AccessPassResources.currentServletPathIsStaticResource(path)) {
               return chain.filter(exchange);
           }
           AtomicBoolean loginSuccess = new AtomicBoolean(false);
           exchange.getSession().subscribe(webSession -> {
               Object loginMember = webSession.getAttribute(SCWConstant.ATTR_NAME_LOGIN_MEMBER);
               if(loginMember!=null){
                   loginSuccess.set(true);
               }else {
                   exchange.getResponse();
                   webSession.getAttributes().put(SCWConstant.ATTR_NAME_MESSAGE, SCWConstant.MESSAGE_ACCESS_FORBIDDEN);
                   loginSuccess.set(false);
               }
           });
           try {
               Thread.sleep(200);
           } catch (InterruptedException e) {
               throw new RuntimeException(e);
           }
           if (loginSuccess.get()) {
               return chain.filter(exchange);
           }
           ServerHttpResponse response = exchange.getResponse();
           response.setStatusCode(HttpStatus.SEE_OTHER);
           response.getHeaders().set(HttpHeaders.LOCATION, "/login.html");
           response.getHeaders().add("Content-Type", "text/plain;charset=UTF-8");
           return response.setComplete();
       }
   
       @Override
       public int getOrder() {
           return -1;
       }
   }

使用SpringCloud Gateway时，如果对应请求的返回结果是重定向，则会改变主机地址为对应微服务的地址(302)？

解决：修改application.yml配置文件PreserveHostHeader，对请求头进行处理

spring:
  cloud:
    gateway:
      routes:
        - id: scw-auth
          uri: lb://SCW-AUTH
          predicates:
          - Path=/**
          filters:
            - PreserveHostHeader

邮箱验证码功能

public class ProjectUtils {
    /**
     * @param fromEmail 发送者邮箱
     * @param licenseCode 发送者邮箱登录凭证
     * @param receiveEmail 接收者邮箱
     * @param codeLength 验证码长度
     * @param name 收件人名称
     * @return
     * @throws MessagingException
     * @throws UnsupportedEncodingException
     */
    public static String sendEmail(String fromEmail, String licenseCode, String receiveEmail, int codeLength, String name) throws MessagingException, UnsupportedEncodingException {
        Properties props = new Properties();
        props.setProperty("mail.transport.protocol", "smtp");     //使用smpt的邮件传输协议
        props.setProperty("mail.smtp.host", "smtp.qq.com");       //主机地址
        props.setProperty("mail.smtp.auth", "true");      //授权通过

        Session session = Session.getInstance(props);     //通过我们的这些配置，得到一个会话程序
        MimeMessage message = new MimeMessage(session);
        message.setFrom(new InternetAddress(fromEmail));     //设置发件人
        message.setRecipient(MimeMessage.RecipientType.TO, new InternetAddress(receiveEmail, "用户", "utf-8"));      //设置收件人
        message.setSubject("邮件验证码", "utf-8");      //设置主题
        message.setSentDate(new Date());
        StringBuilder code = new StringBuilder();
        for (int i = 0; i < codeLength; i++) {
            code.append((int) (Math.random() * 10));
        }
        SimpleDateFormat sdf = new SimpleDateFormat("yyyy年MM月dd日 HH:mm:ss");
        String str = "<!DOCTYPE html><html><head><meta charset='UTF-8'></head><body><p style='font-size: 20px;font-weight:bold;'>尊敬的" + name + ":您好！</p>"
                + "<p style='text-indent:2em; font-size: 20px;'>欢迎注册，您本次的注册码是 "
                + "<span style='font-size:30px;font-weight:bold;color:red'>" + code + "</span>，1分钟之内有效，请尽快使用！</p>"
                + "<p style='text-align:right; padding-right: 20px;'"
                + "<span style='font-size: 18px; float:right; margin-right: 30px;'>" + sdf.format(new Date()) + "</span></body></html>";

        Multipart mul = new MimeMultipart();  //新建一个MimeMultipart对象来存放多个BodyPart对象
        BodyPart mdp = new MimeBodyPart();  //新建一个存放信件内容的BodyPart对象
        mdp.setContent(str, "text/html;charset=utf-8");
        mul.addBodyPart(mdp);  //将含有信件内容的BodyPart加入到MimeMultipart对象中
        message.setContent(mul); //把mul作为消息内容


        message.saveChanges();

        //创建一个传输对象
        Transport transport = session.getTransport("smtp");

        //建立与服务器的链接  465端口是 SSL传输
        transport.connect("smtp.qq.com", 587, fromEmail, licenseCode);

        //发送邮件
        transport.sendMessage(message, message.getAllRecipients());

        //关闭邮件传输
        transport.close();

        return code.toString();

    }
}

OpenFeign远程调用报错

错误内容：

### Error updating database. Cause: java.sql.SQLSyntaxErrorException: You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near '' at line 1 ### The error may exist in file [D:-member-parent-member-mysql-.xml] ### The error may involve com.zephon.scw.mapper.MemberPOMapper.insertSelective-Inline ### The error occurred while setting parameters ### SQL: insert into t_member ### Cause: java.sql.SQLSyntaxErrorException: You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near '' at line 1 ; bad SQL grammar []; nested exception is java.sql.SQLSyntaxErrorException: You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near '' at line 1

解决：

在使用OpenFeign接口时，服务提供者的请求参数中忘写@RequestBody注解了，之后开发中最好将服务提供者和OpenFeign接口对应的方法请求参数需要写的都写上@RequestBody

服务提供者：

@RequestMapping("/save/member/remote")
public ResultEntity<MemberPO> saveMemberPO(@RequestBody MemberPO memberPO){

接口：

@FeignClient("scw-mysql")
public interface MySQLRemoteService {
    @RequestMapping("/save/member/remote")
    ResultEntity<MemberPO> saveMemberPO(@RequestBody MemberPO memberPO);
}

MyBatis插入数据后如何获取生成的ID？

1. 配置Mapper的XML，useGeneratedKeys="true" keyProperty="xxx"如：

   <insert id="insertSelective" useGeneratedKeys="true" keyProperty="id" ...

2. 插入后通过get方法获取生成的id

异步请求中无法对session中的属性进行更新？暂未找到原因，只能侧面解决

问题：

在请求A中设置了Session

@RequestMapping("/A")
public String saveProjectBasicInfo(ProjectVO projectVO,
                                   HttpSession session,
                                   ModelMap modelMap) throws IOException {
    ...
    session.setAttribute(SCWConstant.ATTR_NAME_TEMPLE_PROJECT, projectVO);

在@ResponseBody请求中更新Session:

@ResponseBody
@RequestMapping("/B")
public ResultEntity<String> save(ReturnVO returnVO, HttpSession session) {
    ProjectVO projectVO = (ProjectVO) session.getAttribute(SCWConstant.ATTR_NAME_TEMPLE_PROJECT);
    projectVO.setReturnVOList(new ArrayList<>());
    session.setAttribute(SCWConstant.ATTR_NAME_TEMPLE_PROJECT, projectVO);

在请求C中获取session中的数据，发现之前设置的值是空的

@RequestMapping("/C")
public String createConfirm(HttpSession session){
    ProjectVO projectVO = (ProjectVO) session.getAttribute(SCWConstant.ATTR_NAME_TEMPLE_PROJECT);
    projectVO.getReturnVOList(); // 发现是null

解决方案：未真正解决

猜测：Gateway的问题

侧面解决，换个名：

在请求B中将要添加的属性单独放到session中

@ResponseBody
@RequestMapping("/B")
public ResultEntity<String> save(ReturnVO returnVO, HttpSession session) {
    ProjectVO projectVO = (ProjectVO) session.getAttribute(SCWConstant.ATTR_NAME_TEMPLE_PROJECT);
    projectVO.setReturnVOList(new ArrayList<>());
    session.setAttribute("new_name", projectVO);

然后在请求C中再去获得并设置对应的属性：

@RequestMapping("/C")
public String createConfirm(HttpSession session){
    ProjectVO projectVO = (ProjectVO) session.getAttribute("new_name");

正式解决方案：

之前为了解决Gateway无法通过session判断登录的问题，对Gateway进行了配置：

@EnableRedisWebSession(saveMode = SaveMode.ALWAYS)
@Configuration
public class RedisSessionConfig {
    @Bean
    public WebSessionIdResolver webSessionIdResolver() {
        return new CustomWebSessionIdResolver();
    }

}
class CustomWebSessionIdResolver extends CookieWebSessionIdResolver {
    // 重写resolve方法 对SESSION进行base64解码
    @Override
    public List<String> resolveSessionIds(ServerWebExchange exchange) {
        MultiValueMap<String, HttpCookie> cookieMap = exchange.getRequest().getCookies();
        // 获取SESSION
        List<HttpCookie> cookies = cookieMap.get(getCookieName());
        if (cookies == null) {
            return Collections.emptyList();
        }
        return cookies.stream().map(HttpCookie::getValue).map(this::base64Decode).collect(Collectors.toList());
    }

    private String base64Decode(String base64Value) {
        try {
            byte[] decodedCookieBytes = Base64.getDecoder().decode(base64Value);
            return new String(decodedCookieBytes);
        } catch (Exception ex) {
            System.out.println("Unable to Base64 decode value: " + base64Value);
            return null;
        }
    }
}

这就会导致Session无法更新的问题，所以将其注释后就可以解决这个问题，然后只能通过token对登录进行认证

在创建一个微服务去调用Feign接口时，直接从另一个服务复制过来的包和配置文件进行修改的，但调用Feign接口报找不到Bean错误

1. 检查Main类上面是否有@EnableFeignClients注解
2. 个人遇到问题的原因是IDEA复制包时没有复制多级包，导致我的controller在abc目录下，而Feign接口在com.zephon.abc包下，因此，需要再建一个对应的多级包即可