半夜睡醒出门吃宵夜回家锁坏了,被逼无奈去了网吧正好想起之前构思的消除ifelse的方案正好就试了试,经过几小时奋斗修修改改终于实现了效果,特此分享.
具体的流程如上
大概的场景是 在 web项目中有很多方法是要携带token或其他的操作才可以访问的,一开始只有一个token还好业务繁忙的时候每次都要修改拦截器中的代码十分麻烦.
首先还是新建一个web项目然后自己再写一个拦截器(这里用的是springboot构建的项目)
配置拦截器
@Configuration
public class WebMvcConfig implements WebMvcConfigurer {
@Override
public void addInterceptors(InterceptorRegistry registry) {
// 添加全局 拦截器 interceptor registry.addInterceptor(authenticationInterceptor())
.addPathPatterns("/**");
}
@Bean
public AuthenticationInterceptor authenticationInterceptor() {
return new AuthenticationInterceptor();
}
}
拦截器
public class AuthenticationInterceptor implements HandlerInterceptor {
@Override
public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler) {
HandlerMethod handlerMethod = (HandlerMethod) handler;
Method method = handlerMethod.getMethod();
BaseAnnotation methodAnno = method.getAnnotation(BaseAnnotation.class);
String value = methodAnno.value();
System.out.println(value);
BaseBean bean = SpringUtil.getBean(value,BaseBean.class);
System.out.println(request.getRequestURI());
bean.say();
return true;
}
@Override
public void postHandle(HttpServletRequest request, HttpServletResponse response, Object handler,
ModelAndView modelAndView) {
}
}
测试用的注解
@Target({ElementType.METHOD,ElementType.TYPE})
@Retention(RetentionPolicy.RUNTIME)
public @interface BaseAnnotation {
public String value() default "";
}
接口
public interface BaseBean {
public void say();
}
接口实现类(两个直接写一起了)
@Component
public class BeanA implements BaseBean{
public void say() {
System.out.println( "这是BeanA的say");
}
}
@Component
public class BeanB implements BaseBean{
public void say() {
System.out.println( "这是BeanB的say");
}
}
测试用的控制器
@RestController
@RequestMapping("/test")
public class TestController {
@RequestMapping("/a")
@BaseAnnotation("beanA")
public String testA() {
return "a";
}
@RequestMapping("/b")
@BaseAnnotation("beanB")
public String testB() {
return "b";
}
}
运行结果
localhost:8080/test/a
localhost:8080/test/b
拦截器中用到了一个工具类 SpringUtil 主要作用是用来获取Spring容器中的bean
工具类
@Component
public class SpringUtil implements ApplicationContextAware {
private static ApplicationContext applicationContext;
@Override
public void setApplicationContext(ApplicationContext applicationContext) throws BeansException {
if(SpringUtil.applicationContext == null) {
SpringUtil.applicationContext = applicationContext;
}
}
//获取applicationContext public static ApplicationContext getApplicationContext() {
return applicationContext;
}
//通过name获取 Bean. public static Object getBean(String name){
return getApplicationContext().getBean(name);
}
//通过class获取Bean. public static T getBean(Class clazz){
return getApplicationContext().getBean(clazz);
}
//通过name,以及Clazz返回指定的Bean public static T getBean(String name,Class clazz){
return getApplicationContext().getBean(name, clazz);
}
}
