只有利害关系和出众的才干,才能帮你出起主意来,才认真细到,眼光透彻。——巴尔扎克
我们在web
开发中经常遇到在一个线程中需要共享变量
这里就可以使用ThreadLocal
去完成
例如我们用户发起请求,我们在过滤器等将用户信息存储在ThreadLocal
中,这样在代码中获取用户信息就相对容易
写法如下:
import cn.hutool.core.lang.Opt;
/**
* 用户工具类
*
* @author <achao1441470436@gmail.com>
* @since 2021/8/25 12:10
*/
public class UserUtils {
private static final ThreadLocal<UserDetail> USER_THREAD = new ThreadLocal<>();
/**
* 设置当前用户
*
* @param userDetail 用户信息
* @author <achao1441470436@gmail.com>
* @since 2021/9/10 16:23
*/
public static void setUser(UserDetail userDetail) {
USER_THREAD.set(userDetail);
}
/**
* 移除当前用户
*
* @author <achao1441470436@gmail.com>
* @since 2021/10/22 16:49
*/
public static void clear() {
USER_THREAD.remove();
}
/**
* 获取用户信息,有可能获取不到
*
* @return com.baomidou.shaun.core.profile.TokenProfile
* @author <achao1441470436@gmail.com>
* @since 2021/9/9 10:33
*/
public static Opt<UserDetail> getUser() {
return Opt.ofNullable(USER_THREAD.get()).or(() -> {
// 这里UserDetail从实际登录框架调用对应api获取
UserDetail userDetail = null;
return Opt.of(userDetail);
});
}
}
在拦截器中:
package com.ruben.xchat.interceptor;
import com.ruben.xchat.utils.UserUtils;
import org.springframework.stereotype.Component;
import org.springframework.web.method.HandlerMethod;
import org.springframework.web.servlet.AsyncHandlerInterceptor;
import org.springframework.web.servlet.HandlerInterceptor;
import org.springframework.web.servlet.ModelAndView;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
/**
* 用户信息拦截器
*
* @author <achao1441470436@gmail.com>
* @since 2021/10/22 19:19
*/
@Component
public class UserInfoInterceptor implements HandlerInterceptor {
@Override
public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler) throws Exception {
UserUtils.getUser().ifPresent(UserUtils::setUser);
return true;
}
@Override
public void afterCompletion(HttpServletRequest request, HttpServletResponse response, Object handler, Exception ex) throws Exception {
UserUtils.clear();
}
}
然后别忘了让拦截器生效
@Configuration
@EnableWebMvc
public class WebConfig implements WebMvcConfigurer {
@Resource
private UserInfoInterceptor userInfoInterceptor;
@Override
public void addInterceptors(InterceptorRegistry registry) {
registry.addInterceptor(userInfoInterceptor).addPathPatterns("/**");
}
}