springboot * 过滤token,并返回结果及异常处理操作

1.springboot * 处理过滤token，并且返回结果

import org.apache.commons.lang3.StringUtils;
import org.apache.shiro.subject.Subject;
import org.springframework.lang.Nullable;
import org.springframework.stereotype.Component;
import org.springframework.web.servlet.HandlerInterceptor;
import org.springframework.web.servlet.ModelAndView;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;
import java.io.PrintWriter;
import java.util.Map;

@Component
public class ECInterceptor implements HandlerInterceptor {
 /**
  * @Description 在业务处理器处理请求之前被调用。预处理，可以进行编码、安全控制等处理；
  * @Date 2019/5/14 16:04
  * @Version 1.0
  */
 @Override
 public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler) throws Exception {
   System.out.println(request.getRequestURL()+"===========preHandle===========");
   String token = request.getParameter("token");
   if(StringUtils.isNotEmpty(token)){
     Subject subject = ShiroUtil.getSubject(token);
     if(subject != null && subject.isAuthenticated()){
       return true;
     } else{
       //返回校验token结果
       returnJson(response);
       // return false; //我做的时候返回数据后忘记return false了，所以导致异常
     }
   }
   return true;
 }

@Override
 public void postHandle(HttpServletRequest request, HttpServletResponse response, Object handler, @Nullable ModelAndView modelAndView) throws Exception {
   System.out.println(request.getContextPath()+"============postHandle==========");
 }
 /**
  * @Description 在DispatcherServlet完全处理完请求后被调用，也就是说视图渲染已经完毕或者调用者已经拿到结果
  * @Date 2019/5/14 16:05
  * @Version 1.0
  */
 @Override
 public void afterCompletion(HttpServletRequest request, HttpServletResponse response, Object handler, @Nullable Exception ex) throws Exception {
   System.out.println(request.getContextPath()+"============afterCompletion==========");
 }
 private void returnJson(HttpServletResponse response){
   PrintWriter writer = null;
   response.setCharacterEncoding("UTF-8");
   response.setContentType("application/json; charset=utf-8");
   try {
     writer = response.getWriter();
     Map<String, Object> result = PackageReturnResult.returnJson(400, "用户令牌token无效");
     result.put("data", null);
     writer.print(result);
   } catch (IOException e){
     LoggerUtil.logError(ECInterceptor.class, " * 输出流异常"+e);
   } finally {
     if(writer != null){
       writer.close();
     }
   }
 }
}

2.java.lang.IllegalStateException: getWriter() has already been called for this response异常

我再做 * 处理response数据后忘记return false返回，导致 * 被调用两次，报java.lang.IllegalStateException: getWriter() has already been called for this response异常，犯这样低级错误花了很长时间才解决，谨记！！！

[2019-05-27 09:27:17.690] [http-nio-8080-exec-1        ] [ERROR] [o.a.c.c.C.[.[.[.[dispatcherServlet] :175 ] - Servlet.service() for servlet [dispatcherServlet] in context with path [] threw exception [Request processing failed; nested exception is java.lang.IllegalStateException: getWriter() has already been called for this response] with root cause
java.lang.IllegalStateException: getWriter() has already been called for this response
at org.apache.catalina.connector.Response.getOutputStream(Response.java:548)
at org.apache.catalina.connector.ResponseFacade.getOutputStream(ResponseFacade.java:210)
at javax.servlet.ServletResponseWrapper.getOutputStream(ServletResponseWrapper.java:105)
at org.springframework.http.server.ServletServerHttpResponse.getBody(ServletServerHttpResponse.java:83)
at org.springframework.http.converter.json.AbstractJackson2HttpMessageConverter.writeInternal(AbstractJackson2HttpMessageConverter.java:255)
at org.springframework.http.converter.AbstractGenericHttpMessageConverter.write(AbstractGenericHttpMessageConverter.java:103)
at org.springframework.web.servlet.mvc.method.annotation.AbstractMessageConverterMethodProcessor.writeWithMessageConverters(AbstractMessageConverterMethodProcessor.java:290)
at org.springframework.web.servlet.mvc.method.annotation.RequestResponseBodyMethodProcessor.handleReturnValue(RequestResponseBodyMethodProcessor.java:180)
at com.uufund.ecapi.config.returnvalue.HandlerMethodReturnValueHandlerProxy.handleReturnValue(HandlerMethodReturnValueHandlerProxy.java:40)
at org.springframework.web.method.support.HandlerMethodReturnValueHandlerComposite.handleReturnValue(HandlerMethodReturnValueHandlerComposite.java:82)
at org.springframework.web.servlet.mvc.method.annotation.ServletInvocableHandlerMethod.invokeAndHandle(ServletInvocableHandlerMethod.java:119)
at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.invokeHandlerMethod(RequestMappingHandlerAdapter.java:892)
at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.handleInternal(RequestMappingHandlerAdapter.java:797)
at org.springframework.web.servlet.mvc.method.AbstractHandlerMethodAdapter.handle(AbstractHandlerMethodAdapter.java:87)
at org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:1038)
at org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:942)
at org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:1005)
at org.springframework.web.servlet.FrameworkServlet.doGet(FrameworkServlet.java:897)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:634)
at org.springframework.web.servlet.FrameworkServlet.service(FrameworkServlet.java:882)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:741)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:231)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166)
at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:53)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166)
at org.apache.shiro.web.servlet.AbstractShiroFilter.executeChain(AbstractShiroFilter.java:449)
at org.apache.shiro.web.servlet.AbstractShiroFilter$1.call(AbstractShiroFilter.java:365)
at org.apache.shiro.subject.support.SubjectCallable.doCall(SubjectCallable.java:90)
at org.apache.shiro.subject.support.SubjectCallable.call(SubjectCallable.java:83)
at org.apache.shiro.subject.support.DelegatingSubject.execute(DelegatingSubject.java:387)
at org.apache.shiro.web.servlet.AbstractShiroFilter.doFilterInternal(AbstractShiroFilter.java:362)
at org.apache.shiro.web.servlet.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:125)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166)
at com.uufund.ecapi.config.filter.ECWebFilter.doFilter(ECWebFilter.java:24)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166)
at org.springframework.web.filter.RequestContextFilter.doFilterInternal(RequestContextFilter.java:99)
at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166)
at org.springframework.web.filter.FormContentFilter.doFilterInternal(FormContentFilter.java:92)
at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166)
at org.springframework.web.filter.HiddenHttpMethodFilter.doFilterInternal(HiddenHttpMethodFilter.java:93)
at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166)
at org.springframework.web.filter.CharacterEncodingFilter.doFilterInternal(CharacterEncodingFilter.java:200)
at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166)
at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:200)
at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:96)
at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:490)
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:139)
at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:92)
at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:74)
at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:343)
at org.apache.coyote.http11.Http11Processor.service(Http11Processor.java:408)
at org.apache.coyote.AbstractProcessorLight.process(AbstractProcessorLight.java:66)
at org.apache.coyote.AbstractProtocol$ConnectionHandler.process(AbstractProtocol.java:834)
at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:1415)
at org.apache.tomcat.util.net.SocketProcessorBase.run(SocketProcessorBase.java:49)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624)
at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61)
at java.lang.Thread.run(Thread.java:748)

补充知识：springboot * 过滤权限和错误处理

先说异常处理，增加一个异常处理的类MyControllerAdvice就可以了，不需要其他地方使用，注意使用注解@ControllerAdvice

@ControllerAdvice
public class MyControllerAdvice {
 @Resource
 GetRootPath getRootPath;
 private static final Logger logger = LoggerFactory.getLogger(MyControllerAdvice.class);

public void output(Object json, HttpServletRequest request, HttpServletResponse response) throws IOException {
   String header = request.getHeader("Origin");
   response.setContentType("application/json;charset=UTF-8;");
   PrintWriter out = response.getWriter();
   out.println(json);
   out.flush();
   out.close();
 }

/***
  * 404处理
  * @param e
  * @return
  */
 @ExceptionHandler(NoHandlerFoundException.class)
 public void notFountHandler(HttpServletRequest request, HttpServletResponse response, Model model, NoHandlerFoundException e) throws IOException, JSONException {
   JSONObject json = new JSONObject();
   json.put("code", 500);
   json.put("content", null);
   json.put("msg", "未找到路径："+request.getServletPath());
   output(json,request,response);
 }

/**
  * 运行时异常
  *
  * @param exception
  * @return
  */
 @ExceptionHandler({RuntimeException.class})
 @ResponseStatus(HttpStatus.OK)
 public void processException(HttpServletRequest request, HttpServletResponse response, Model model, RuntimeException exception) throws JSONException, IOException {
   JSONObject json = new JSONObject();
   json.put("code", 500);
   json.put("content", null);
   json.put("msg", exception.getMessage());
   output(json,request,response);
 }

/**
  * Excepiton异常
  *
  * @param exception
  * @return
  */
 @ExceptionHandler({Exception.class})
 @ResponseStatus(HttpStatus.OK)
 public void processException(HttpServletRequest request, HttpServletResponse response, Model model, Exception exception) throws JSONException, IOException {
   JSONObject json = new JSONObject();
   json.put("code", 500);
   json.put("content", null);
   json.put("msg", exception.getMessage());
   output(json,request,response);
 }
}

再来权限验证的，接手的项目框架中只有验证是否登录的，没有验收权限的，增加一个类WebMvcConfig，注意使用注解@Configuration， 不需要在其他地方引用即可起作用，并注意使用excludePathPatterns去掉不需要拦截的部分，否则会拦截掉静态资源。

@Configuration
public class WebMvcConfig implements WebMvcConfigurer {

/**
  * 添加 *
  */
 @Override
 public void addInterceptors(InterceptorRegistry registry) {
   //静态资源不拦截
   registry.addInterceptor(new LoginInterceptor()).addPathPatterns("/**").excludePathPatterns("/static/**");
 }
}

增加 * 类LoginInterceptor

public class LoginInterceptor extends HandlerInterceptorAdapter {

/**
  * 检查是否已经登录
  */
 @Override
 public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler) throws Exception {
   Object username = request.getSession().getAttribute(Constants.LOGIN_USER);
   String servletPath = request.getServletPath();
   String type = request.getHeader("X-Requested-With") == null ? "" : request.getHeader("X-Requested-With");

if (username != null) {
     //检查页面访问的权限
     if (!"XMLHttpRequest".equals(type)) {
       int userId = Integer.valueOf(request.getSession().getAttribute(Constants.LOGIN_USERID).toString());
       List<ModuleEntity> moduleList = (List<ModuleEntity>) request.getSession().getAttribute(Constants.USER_MODULE);
       boolean chkResult = methodPermissionLimit(moduleList, servletPath);
       if(!chkResult){
         JSONObject outputMSg = new JSONObject();
         outputMSg.put("code", 500);
         outputMSg.put("content", "");
         outputMSg.put("msg", "没有权限");
         output(outputMSg, request, response);
         return false;
       }else{
         return true;
       }
     } else {
       //如果是json访问，则不做检查
       return true;
     }
   } else {
     //检查是否登录允许
     if (methodLoginLimit(handler)) {
       return true;
     } else {
       if ("XMLHttpRequest".equals(type)) {
         JSONObject outputMSg = new JSONObject();
         outputMSg.put("code", 500);
         outputMSg.put("content", "");
         outputMSg.put("msg", "登录过期，请重新登陆");
         output(outputMSg, request, response);
         return false;
       } else {
         String redirectUrl = request.getContextPath() + "/login";
         response.sendRedirect(redirectUrl);
         return false;
       }
     }
   }
 }

public boolean methodLoginLimit(Object handler) {
   HandlerMethod method = (HandlerMethod) handler;
   //获取当前方法PermessionLimit
   LoginLimit loginLimit = method.getMethodAnnotation(LoginLimit.class);
   if (loginLimit == null) {
     //获取控制器的PermessionLimit
     loginLimit = method.getMethod().getDeclaringClass().getAnnotation(LoginLimit.class);
   }
   if (loginLimit != null && !loginLimit.limit()) {
     return true;
   } else {
     return false;
   }
 }

/**
  * 检查权限
  *
  * @param moduleList
  * @param path
  * @return
  */
 public boolean methodPermissionLimit(List<ModuleEntity> moduleList, String path) {
   boolean havePermission = moduleList.stream().anyMatch(f->f.getPath().toLowerCase().equals(path.toLowerCase()));
   return havePermission;
 }

public void output(Object json, HttpServletRequest request, HttpServletResponse response) throws IOException {
   String header = request.getHeader("Origin");
   response.setContentType("application/json;charset=UTF-8;");
   PrintWriter out = response.getWriter();
   out.println(json);
   out.flush();
   out.close();
 }
}

这样的 * 只对页面地址进行拦截，对ajax提交的数据不做处理，做普通项目的权限过滤是可以了。

来源：https://blog.csdn.net/yaomingyang/article/details/90597659