Springboot自定义starter

一、start背景和简介

1.背景

工作中经常需要将多个springboot项目共同的非业务模块抽取出来，比如访问日志、维护请求上下文中的用户信息或者链路id等等。此次模拟的是请求中用户信息维护，方便整个请求中用户信息的取用。

2.作用

根据项目组的实际需求，封装starter，可以简化开发，统一规范的效果。

3.规范

官方的starter包规范：spring-boot-starter-xxx

自定义starter包规范：xxx-spring-boot-starter

二、stater定义

1.创建maven项目（trace-spring-boot-stater），并添加依赖

"1.0" encoding="UTF-8"?>
"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">
    4.0.0
 
    com.su
    trace-spring-boot-starter
    1.0-SNAPSHOT
 
    
    
        org.springframework.boot
        spring-boot-starter-parent
        2.3.4.RELEASE
    
 
    
       
        
            org.springframework.boot
            spring-boot-autoconfigure
        
 
        
            org.springframework.boot
            spring-boot-configuration-processor
            true
        
 
        
            org.projectlombok
            lombok
            1.18.24
        
        
            com.alibaba
            transmittable-thread-local
            2.13.2
        
        
            org.apache.commons
            commons-lang3
        
    
 

2.UserInfo  定义请求上下文内容的类

@Data
public class UserInfo {
    private String traceId;
 
    private String spanId;
 
    private String userNo;
}
 

3.UserContext 实现同一个或父子线程中上下文用户信息的取用

public class UserContext {
    public static final TransmittableThreadLocal userInfo = new TransmittableThreadLocal<>();
 
    private UserContext() {
    }
 
    public static void set(UserInfo user) {
        userInfo.set(user);
    }
 
    public static UserInfo get() {
        return (UserInfo) userInfo.get();
    }
 
    public static void remove() {
        userInfo.remove();
    }
 
 
    public static String userNo() {
        UserInfo userInfo = (UserInfo) UserContext.userInfo.get();
        return Objects.isNull(userInfo) ? null : userInfo.getUserNo();
    }
}

4.UserContextInterceptor 拦截器，拦截请求中的信息并存储

@Slf4j
@Component
public class UserContextInterceptor implements HandlerInterceptor {
    private static final String TRACE_ID = "traceId";
    private static final String SPAN_ID = "spanId";
    private static final String APP_ID = "appId";
    private static final String USER_NO = "userNo";
 
    @Resource
    private AppIdsConfig appIdsConfig;
 
    @Override
    public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler) {
        // 验证请求方的 AppId
        String appId = request.getHeader(APP_ID);
        Set appIdsSet = appIdsConfig.getIdsSet();
        if (StringUtils.isBlank(appId) || CollectionUtils.isEmpty(appIdsSet) || !appIdsSet.contains(appId)) {
            returnJson(response, ComResponse.fail(ResponseCodeEnums.AUTHOR_ERROR_CODE));
            return false;
        }
 
        String spanId = UUIDGenerator.getUUID();
        String traceId = request.getHeader(TRACE_ID);
        String userNo = request.getHeader(USER_NO);
        if (StringUtils.isEmpty(traceId)) {
            traceId = UUIDGenerator.getUUID();
        }
 
        UserInfo userInfo = new UserInfo();
        userInfo.setUserNo(userNo);
        userInfo.setTraceId(traceId);
        userInfo.setSpanId(spanId);
        UserContext.set(userInfo);
 
        MDC.put(TRACE_ID, traceId);
        MDC.put(SPAN_ID, spanId);
 
        log.info("{requestServer:{},traceId:{},spanId:{}}", appId, traceId, spanId);
        return true;
    }
 
    @Override
    public void afterCompletion(HttpServletRequest request, HttpServletResponse response, Object handler, Exception ex) {
        UserContext.remove();
        MDC.remove(TRACE_ID);
        MDC.remove(SPAN_ID);
    }
 
 
    private void returnJson(HttpServletResponse response, ComResponse