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本篇内容主要讲解“SecurityUtils.getSubject().getPrincipal()为null的问题怎么解决”，感兴趣的朋友不妨来看看。本文介绍的方法操作简单快捷，实用性强。下面就让小编来带大家学习“SecurityUtils.getSubject().getPrincipal()为null的问题怎么解决”吧!
我在项目中获取getUserId(),和getUserName()获取不到值。
他们都是通过SecurityUtils.getSubject().getPrincipal()去获取的。
反复测试发现原因是 ：在shiroConfig里面：
该方法，注意（是该接口名）被写为anon,不通过验证，即：
filterMap.put("/druid/**", “anon”);这种写法是为了postman测试时不被拦截。
从页面访问后端不需要anon了。
anon是不做拦截，authc是走自定义拦截
oauth3是自带拦截
修改为：
filterMap.put("/druid/**", “authc”);1.总的来说，SecurityUtils.getSubject()是每个请求创建一个Subject, 并保存到ThreadContext的resources（ThreadLocal<Map<Object, Object>>）变量中，也就是一个http请求一个subject,并绑定到当前过程。
问题来了：.subject.login()登陆认证成功后，下一次请求如何知道是那个用户的请求呢？
友情提示：本文唯一可以读一下的就是分析这个疑问，如果你已经明白就不用往下看了。
首先给出内部原理：1个请求1个Subject原理:由于ShiroFilterFactoryBean本质是个AbstractShiroFilter过滤器，所以每次请求都会执行doFilterInternal里面的createSubject方法。
猜想：因为subject是绑定到当前线程,这肯定需要一个中介存储状态
public static Subject getSubject() {
Subject subject = ThreadContext.getSubject();
if (subject == null) {
subject = (new Builder()).buildSubject();
ThreadContext.bind(subject);
}
return subject;
}public abstract class ThreadContext {
private static final Logger log = LoggerFactory.getLogger(ThreadContext.class);
public static final String SECURITY_MANAGER_KEY = ThreadContext.class.getName() + "_SECURITY_MANAGER_KEY";
public static final String SUBJECT_KEY = ThreadContext.class.getName() + "_SUBJECT_KEY";
private static final ThreadLocal<Map<Object, Object>> resources = new ThreadContext.InheritableThreadLocalMap();
protected ThreadContext() {
}
public static Map<Object, Object> getResources() {
return (Map)(resources.get() == null ? Collections.emptyMap() : new HashMap((Map)resources.get()));
}
public static void setResources(Map<Object, Object> newResources) {
if (!CollectionUtils.isEmpty(newResources)) {
ensureResourcesInitialized();
((Map)resources.get()).clear();
((Map)resources.get()).putAll(newResources);
}
}
private static Object getValue(Object key) {
Map<Object, Object> perThreadResources = (Map)resources.get();
return perThreadResources != null ? perThreadResources.get(key) : null;
}
private static void ensureResourcesInitialized() {
if (resources.get() == null) {
resources.set(new HashMap());
}
}
public static Object get(Object key) {
if (log.isTraceEnabled()) {
String msg = "get() - in thread [" + Thread.currentThread().getName() + "]";
log.trace(msg);
}
Object value = getValue(key);
if (value != null && log.isTraceEnabled()) {
String msg = "Retrieved value of type [" + value.getClass().getName() + "] for key [" + key + "] bound to thread [" + Thread.currentThread().getName() + "]";
log.trace(msg);
}
return value;
}
public static void put(Object key, Object value) {
if (key == null) {
throw new IllegalArgumentException("key cannot be null");
} else if (value == null) {
remove(key);
} else {
ensureResourcesInitialized();
((Map)resources.get()).put(key, value);
if (log.isTraceEnabled()) {
String msg = "Bound value of type [" + value.getClass().getName() + "] for key [" + key + "] to thread [" + Thread.currentThread().getName() + "]";
log.trace(msg);
}
}
}
public static Object remove(Object key) {
Map<Object, Object> perThreadResources = (Map)resources.get();
Object value = perThreadResources != null ? perThreadResources.remove(key) : null;
if (value != null && log.isTraceEnabled()) {
String msg = "Removed value of type [" + value.getClass().getName() + "] for key [" + key + "]from thread [" + Thread.currentThread().getName() + "]";
log.trace(msg);
}
return value;
}
public static void remove() {
resources.remove();
}
public static SecurityManager getSecurityManager() {
return (SecurityManager)get(SECURITY_MANAGER_KEY);
}
public static void bind(SecurityManager securityManager) {
if (securityManager != null) {
put(SECURITY_MANAGER_KEY, securityManager);
}
}
public static SecurityManager unbindSecurityManager() {
return (SecurityManager)remove(SECURITY_MANAGER_KEY);
}
public static Subject getSubject() {
return (Subject)get(SUBJECT_KEY);
}
public static void bind(Subject subject) {
if (subject != null) {
put(SUBJECT_KEY, subject);
}
}
public static Subject unbindSubject() {
return (Subject)remove(SUBJECT_KEY);
}
private static final class InheritableThreadLocalMap<T extends Map<Object, Object>> extends InheritableThreadLocal<Map<Object, Object>> {
private InheritableThreadLocalMap() {
}
protected Map<Object, Object> childValue(Map<Object, Object> parentValue) {
return parentValue != null ? (Map)((HashMap)parentValue).clone() : null;
}
}
}subject登陆成功后，下一次请求如何知道是那个用户的请求呢？
经过源码分析，核心实现如下DefaultSecurityManager类中：
public Subject createSubject(SubjectContext subjectContext) {
SubjectContext context = this.copy(subjectContext);
context = this.ensureSecurityManager(context);
context = this.resolveSession(context);
context = this.resolvePrincipals(context);
Subject subject = this.doCreateSubject(context);
this.save(subject);
return subject;
}每次请求都会重新设置Session和Principals,看到这里大概就能猜到：如果是web工程，直接从web容器获取httpSession，然后再从httpSession获取Principals，本质就是从cookie获取用户信息，然后每次都设置Principal，这样就知道是哪个用户的请求，并只得到这个用户有没有人认证成功，--本质：依赖于浏览器的cookie来维护session的
扩展，如果不是web容器的app,如何实现实现无状态的会话
1.一般的作法会在header中带有一个token，或者是在参数中，后台根据这个token来进行校验这个用户的身份，但是这个时候，servlet中的session就无法保存，我们在这个时候，就要实现自己的会话创建，普通的作法就是重写session与request的接口，然后在过滤器在把它替换成自己的request,所以得到的session也是自己的session，然后根据token来创建和维护会话
2.shiro实现：
重写shiro的sessionManage
import org.apache.shiro.session.mgt.SessionKey;
import org.apache.shiro.web.servlet.ShiroHttpServletRequest;
import org.apache.shiro.web.session.mgt.DefaultWebSessionManager;
import org.apache.shiro.web.util.WebUtils;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import javax.servlet.ServletRequest;
import javax.servlet.ServletResponse;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.Serializable;
import java.util.UUID;
/**
* @author zxj<br>
* 时间 2017/11/8 15:55
* 说明 ...
*/
public class StatelessSessionManager extends DefaultWebSessionManager {
/**
* 这个是服务端要返回给客户端，
*/
public final static String TOKEN_NAME = "TOKEN";
/**
* 这个是客户端请求给服务端带的header
*/
public final static String HEADER_TOKEN_NAME = "token";
public final static Logger LOG = LoggerFactory.getLogger(StatelessSessionManager.class);
@Override
public Serializable getSessionId(SessionKey key) {
Serializable sessionId = key.getSessionId();
if(sessionId == null){
HttpServletRequest request = WebUtils.getHttpRequest(key);
HttpServletResponse response = WebUtils.getHttpResponse(key);
sessionId = this.getSessionId(request,response);
}
HttpServletRequest request = WebUtils.getHttpRequest(key);
request.setAttribute(TOKEN_NAME,sessionId.toString());
return sessionId;
}
@Override
protected Serializable getSessionId(ServletRequest servletRequest, ServletResponse servletResponse) {
HttpServletRequest request = (HttpServletRequest) servletRequest;
String token = request.getHeader(HEADER_TOKEN_NAME);
if(token == null){
token = UUID.randomUUID().toString();
}
//这段代码还没有去查看其作用，但是这是其父类中所拥有的代码，重写完后我复制了过来...开始
request.setAttribute(ShiroHttpServletRequest.REFERENCED_SESSION_ID_SOURCE,
ShiroHttpServletRequest.COOKIE_SESSION_ID_SOURCE);
request.setAttribute(ShiroHttpServletRequest.REFERENCED_SESSION_ID, token);
request.setAttribute(ShiroHttpServletRequest.REFERENCED_SESSION_ID_IS_VALID, Boolean.TRUE);
request.setAttribute(ShiroHttpServletRequest.SESSION_ID_URL_REWRITING_ENABLED, isSessionIdUrlRewritingEnabled());
//这段代码还没有去查看其作用，但是这是其父类中所拥有的代码，重写完后我复制了过来...结束
return token;
}
}
@RequestMapping("/")
public void login(@RequestParam("code")String code, HttpServletRequest request){
Map<String,Object> data = new HashMap<>();
if(SecurityUtils.getSubject().isAuthenticated()){
//这里代码着已经登陆成功，所以自然不用再次认证，直接从rquest中取出就行了，
data.put(StatelessSessionManager.HEADER_TOKEN_NAME,getServerToken());
data.put(BIND,ShiroKit.getUser().getTel() != null);
response(data);
}
LOG.info("授权码为:" + code);
AuthorizationService authorizationService = authorizationFactory.getAuthorizationService(Constant.clientType);
UserDetail authorization = authorizationService.authorization(code);
Oauth3UserDetail userDetail = (Oauth3UserDetail) authorization;
loginService.login(userDetail);
User user = userService.saveUser(userDetail,Constant.clientType.toString());
ShiroKit.getSession().setAttribute(ShiroKit.USER_DETAIL_KEY,userDetail);
ShiroKit.getSession().setAttribute(ShiroKit.USER_KEY,user);
data.put(BIND,user.getTel() != null);
//这里的代码，必须放到login之执行，因为login后，才会创建session，才会得到最新的token咯
data.put(StatelessSessionManager.HEADER_TOKEN_NAME,getServerToken());
response(data);
}
}import org.apache.shiro.mgt.SecurityManager;
import org.apache.shiro.realm.Realm;
import org.apache.shiro.spring.LifecycleBeanPostProcessor;
import org.apache.shiro.spring.web.ShiroFilterFactoryBean;
import org.apache.shiro.web.mgt.DefaultWebSecurityManager;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import java.util.LinkedHashMap;
import java.util.Map;
/**
* @author zxj<br>
* 时间 2017/11/8 15:40
* 说明 ...
*/
@Configuration
public class ShiroConfiguration {
@Bean
public LifecycleBeanPostProcessor lifecycleBeanPostProcessor(){
return new LifecycleBeanPostProcessor();
}
/**
* 此处注入一个realm
* @param realm
* @return
*/
@Bean
public SecurityManager securityManager(Realm realm){
DefaultWebSecurityManager securityManager = new DefaultWebSecurityManager();
securityManager.setSessionManager(new StatelessSessionManager());
securityManager.setRealm(realm);
return securityManager;
}
@Bean
public ShiroFilterFactoryBean shiroFilterFactoryBean(SecurityManager securityManager){
ShiroFilterFactoryBean bean = new ShiroFilterFactoryBean();
bean.setSecurityManager(securityManager);
Map<String,String> map = new LinkedHashMap<>();
map.put("/public/**","anon");
map.put("/login/**","anon");
map.put("/**","user");
bean.setFilterChainDefinitionMap(map);
return bean;
}
}到此，相信大家对“SecurityUtils.getSubject().getPrincipal()为null的问题怎么解决”有了更深的了解，不妨来实际操作一番吧！这里是亿速云网站，更多相关内容可以进入相关频道进行查询，关注我们，继续学习！
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