项目应用：web项目从拦截请求获取用户

来源：互联网发布：mac os x系统镜像编辑：程序博客网时间：2024/05/21 10:41

首选说下要求背景，用户通过网站登录后会将用户的基本信息记录在session，而当有请求需要用到用户信息的时候，每个方法都需要自己从session中拉取用户信息，而获取不到时还需要去处理跳转登录的操作，十分麻烦。因此考虑到开发的方便性，希望可以用到注解的方式直接将用户信息封装好，作为参数传递给各个请求。

首先有个用户的Vo类

    public class UserVO {                            private int id=0;          private String ticket=""; //唯一证书          private String username=""; //用户名          private String nickname="";//昵称          private String avatar="";//头像          private int gender=0;// 性别          private String phone="";//电话          private String  email="";//邮箱          private int  role=0;//用户权限                    //认证信息          private String access_token="";          private String refresh_token="";           private Integer expires_in=0;                    public String getUsername() {              return username;          }          public void setUsername(String username) {              this.username = username;          }                 public String getNickname() {              return nickname;          }          public void setNickname(String nickname) {              this.nickname = nickname;          }          public String getAvatar() {              return avatar;          }          public void setAvatar(String avatar) {              this.avatar = avatar;          }          public int getGender() {              return gender;          }          public void setGender(int gender) {              this.gender = gender;          }          public String getPhone() {              return phone;          }          public void setPhone(String phone) {              this.phone = phone;          }          public String getEmail() {              return email;          }          public void setEmail(String email) {              this.email = email;          }                        public String getTicket() {                      return ticket;              }              public void setTicket(String ticket) {                      this.ticket = ticket;              }          public int getId() {              return id;          }          public void setId(int id) {              this.id = id;          }                     public String getAccess_token() {              return access_token;          }          public void setAccess_token(String access_token) {              this.access_token = access_token;          }          public String getRefresh_token() {              return refresh_token;          }          public void setRefresh_token(String refresh_token) {              this.refresh_token = refresh_token;          }          public Integer getExpires_in() {              return expires_in;          }          public void setExpires_in(Integer expires_in) {              this.expires_in = expires_in;          }          public int getRole() {              return role;          }          public void setRole(int role) {              this.role = role;          }             }

建立个参数级的注解，用于注入用户信息

    @Target({ElementType.PARAMETER})        @Retention(RetentionPolicy.RUNTIME)        @Documented        public @interface UserVo {                    /**          * The URI template variable to bind to.          */          String value() default "";      }

建立解释器从session中获得用户

    public class UserArgumentResolver implements HandlerMethodArgumentResolver{            /**      * 定义解释器支持解析的参数      */      @Override      public boolean supportsParameter(MethodParameter parameter) {          return parameter.getParameterAnnotation(UserVo.class) != null;        }            @Override      public UserVO resolveArgument(MethodParameter parameter,              ModelAndViewContainer mavContainer, NativeWebRequest webRequest,              WebDataBinderFactory binderFactory) throws Exception {              HttpServletRequest request= (HttpServletRequest) webRequest.getNativeRequest();              //从session中获取用户信息              UserVO userInfo=(UserVO)request.getSession().getAttribute("userInfo");              return userInfo;          }      }

最后在xml中加入解释器

<mvc:annotation-driven>      <mvc:argument-resolvers>          <!-- 自定义标签获得UserVO-->           <bean class="com.xx.xx.UserArgumentResolver" />      </mvc:argument-resolvers>  </mvc:annotation-driven>

配合拦截器一起使用，当请求发生的时候先进入拦截器判断session中的用户信息是否为null，不为空进入解释器获取，为空直接进入登录页面

定义拦截器：

    public class UserInterceptor implements HandlerInterceptor{                        @Override            public void afterCompletion(HttpServletRequest request,                    HttpServletResponse response, Object obj, Exception err)                            throws Exception {            }                  @Override            public void postHandle(HttpServletRequest request, HttpServletResponse response,                    Object obj, ModelAndView mav) throws Exception {            }                  @Override            public boolean preHandle(HttpServletRequest request, HttpServletResponse response,                    Object obj) throws Exception {                HttpSession session = request.getSession();              UserVO userInfo = (UserVO) session.getAttribute("userInfo");              String url = request.getRequestURI();              if((userInfo==null)              {                  //不符合条件的，跳转到登录界面                   response.sendRedirect("/login");                  return false;                }              request.setAttribute("userInfo", userInfo);              return true;            }              }

xml中配置拦截规则

    <mvc:interceptors>          <mvc:interceptor>              <mvc:mapping path="/*"/>              <bean class="xx.xx.xx.UserInterceptor"></bean>          </mvc:interceptor>      </mvc:interceptors>

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