自定义注解的使用(将request参数中的数据解释成对象)

项目中,每个controller方法都需要验证用户登录,这里工程写了一个简单的注解,来将cookie中的用户信息还原成对象

注解类

package com.cheshangma.operation.wx.annotation;import java.lang.annotation.Documented;import java.lang.annotation.ElementType;import java.lang.annotation.Retention;import java.lang.annotation.RetentionPolicy;import java.lang.annotation.Target;@Target(ElementType.PARAMETER)@Retention(RetentionPolicy.RUNTIME)//@Retention(RetentionPolicy.SOURCE)    //注解仅存在于源码中，在class字节码文件中不包含//@Retention(RetentionPolicy.CLASS)       // 默认的保留策略，注解会在class字节码文件中存在，但运行时无法获得//@Retention(RetentionPolicy.RUNTIME)   // 注解会在class字节码文件中存在，在运行时可以通过反射获取到@Documentedpublic @interface ObjectConvertAnno {  /**   * 指定该参数的值是否允许为 null 默认是不允许 Whether the parameter is required.   * <p>   * Default is <code>true</code>, leading to an exception thrown in case of the parameter missing   * in the request. Switch this to <code>false</code> if you prefer a <code>null</value> in case of   * the parameter missing.   */  boolean required() default true;}

然后写注解的实现方法

package com.cheshangma.operation.wx.configuration;import javax.servlet.http.HttpServletRequest;import org.springframework.beans.BeansException;import org.springframework.context.ApplicationContext;import org.springframework.context.ApplicationContextAware;import org.springframework.context.annotation.Configuration;import org.springframework.core.MethodParameter;import org.springframework.web.bind.support.WebDataBinderFactory;import org.springframework.web.context.request.NativeWebRequest;import org.springframework.web.method.support.HandlerMethodArgumentResolver;import org.springframework.web.method.support.ModelAndViewContainer;import com.cheshangma.operation.entity.ThirdPartUserEntity;import com.cheshangma.operation.entity.UserEntity;import com.cheshangma.operation.wx.annotation.ObjectConvertAnno;import com.cheshangma.operation.wx.service.ThirdPartUserService;import com.cheshangma.operation.wx.service.UserService;@Configurationpublic class ObjectConvertResolver    implements      HandlerMethodArgumentResolver,      ApplicationContextAware {  private static boolean isReloaded = false;  private static ApplicationContext applicationContext;  private UserService userService;  private ThirdPartUserService thirdPartUserService;  /**  *  *判断是否支持要转换的参数类型   *  */  @Override  public boolean supportsParameter(MethodParameter parameter) {    return parameter.getParameterAnnotation(ObjectConvertAnno.class) != null;  }  /**  *当supportsParameter返回true,支持后进行相应的转换   *  */  @Override  public Object resolveArgument(MethodParameter parameter, ModelAndViewContainer mavContainer,      NativeWebRequest webRequest, WebDataBinderFactory binderFactory) throws Exception {    Object[] paramAnnos = parameter.getParameterAnnotations();    if (paramAnnos == null || paramAnnos.length == 0) {      return new Object();    }    for (Object anno : paramAnnos) {      if (!ObjectConvertAnno.class.isInstance(anno)) {        continue;      }      ObjectConvertAnno objectConvertAnno = (ObjectConvertAnno) anno;      Object object = execute(parameter, webRequest);      if (objectConvertAnno.required() && object == null) {        return null;      }      return object;    }    return new Object();  }  private Object execute(MethodParameter methodParameter, NativeWebRequest webRequest) {    Class<?> paramType = methodParameter.getParameterType();    if (paramType.equals(UserEntity.class)) {      return getCurrentUser((HttpServletRequest) webRequest.getNativeRequest());    } else if (paramType.equals(ThirdPartUserEntity.class)) {      return getCurrentThirdPartUser((HttpServletRequest) webRequest.getNativeRequest());    }    return null;  }  /**   * 获取当前用户   *    * @return   */  private UserEntity getCurrentUser(HttpServletRequest request) {    synchronized (ObjectConvertResolver.class) {      while (!isReloaded) {        try {          ObjectConvertResolver.class.wait();        } catch (InterruptedException e) {          e.printStackTrace();        }      }      // TODO 这里写业务      userService = ObjectConvertResolver.applicationContext          .getBean(com.cheshangma.operation.wx.service.UserService.class);      return userService.getWeChatCurrentUser(request);    }  }  /**   * 获取当前登陆的第三方用户   *    * @return   */  private ThirdPartUserEntity getCurrentThirdPartUser(HttpServletRequest request) {    synchronized (ObjectConvertResolver.class) {      while (!isReloaded) {        try {          ObjectConvertResolver.class.wait();        } catch (InterruptedException e) {          e.printStackTrace();        }      }      // TODO 这里写业务      thirdPartUserService = ObjectConvertResolver.applicationContext          .getBean(com.cheshangma.operation.wx.service.ThirdPartUserService.class);      return thirdPartUserService.getWeChatCurrentUser(request);    }  }  @Override  public void setApplicationContext(ApplicationContext applicationContext) throws BeansException {    synchronized (ObjectConvertResolver.class) {      ObjectConvertResolver.applicationContext = applicationContext;      isReloaded = true;      ObjectConvertResolver.class.notifyAll();    }  }}

这里的thirdPartUserService.getWeChatCurrentUser(request);和userService.getWeChatCurrentUser(request);实现差不多,就贴一个的

@Override  public UserEntity getWeChatCurrentUser(HttpServletRequest request) {    UserEntity user = null;    Cookie cookie = CookieUtils.getCookie(request, PRINCIPALCOOKIE_NAME);    if (cookie == null) {      return null;    }    String cookieValue = cookie.getValue();    LOG.info("cookie="+cookie.getName()+"="+cookieValue);    if (cookieValue == null) {      return null;    }    String[] values = cookieValue.split(SPLIT);    String id = values[0];    LOG.info("userid:"+id);    String cookieSHAValue = values[1];    user = userRepository.findOne(id);    if (user == null) {      return null;    }    String summary = null;    try {      summary = SHACoder.encryptShaB64(user.getId(),user.getId());    } catch (Exception e) {      LOG.error(e.getMessage());      return null;    }    if (summary == null || !summary.equals(cookieSHAValue)) {      return null;    } else {      return user;    }  }

这样就可以了.