1.2 拦截器和过滤器的区别
- 归属不同:Filter属于Servlet技术,Interceptor属于SpringMVC技术
- 拦截内容不同:Filter对所有访问进行增强,Interceptor仅针对SpringMVC的访问进行增强
【第一步】定义拦截器
做法:定义一个类,实现handlerinterceptor接口即可
@Component //注意当前类必须受spring容器控制
//定义拦截器类,实现handlerinterceptor接口
public class ProjectInterceptor implements handlerinterceptor {
@Override
//原始方法调用前执行的内容
//返回值类型可以拦截控制的执行,true放行,false终止
public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler) throws Exception {
System.out.println("preHandle..."+contentType);
return true;
}
@Override
//原始方法调用后执行的内容
public void postHandle(HttpServletRequest request, HttpServletResponse response, Object handler, ModelAndView modelAndView) throws Exception {
System.out.println("postHandle...");
}
@Override
//原始方法调用完成后执行的内容
public void afterCompletion(HttpServletRequest request, HttpServletResponse response, Object handler, Exception ex) throws Exception {
System.out.println("afterCompletion...");
}
}
【第二步】配置加载拦截器
@Configuration
public class SpringMvcSupport extends WebMvcConfigurationSupport {
@Autowired
private ProjectInterceptor projectInterceptor;
@Override
protected void addInterceptors(InterceptorRegistry registry) {
//配置拦截器
registry.addInterceptor(projectInterceptor)
.addpathPatterns("/books","/books/*");
}
}
或使用标准接口WebMvcConfigurer简化开发(注意:侵入式较强)
@Configuration
@ComponentScan({"com.controller"})
@EnableWebMvc
//实现WebMvcConfigurer接口可以简化开发,但具有一定的侵入性
public class SpringMvcConfig implements WebMvcConfigurer {
@Autowired
private ProjectInterceptor projectInterceptor;
@Override
public void addInterceptors(InterceptorRegistry registry) {
//配置多拦截器
registry.addInterceptor(projectInterceptor)
.addpathPatterns("/books","/books/*");
}
}
拦截器流程分析
3 拦截器参数
3.1 前置处理
//原始方法调用前执行的内容
//返回值类型可以拦截控制的执行,true放行,false终止
public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler) throws Exception {
System.out.println("preHandle..."+contentType);
return true;
}
-
参数
-
返回值
返回值为false,被拦截的处理器将不执行。
//原始方法调用后执行的内容
public void postHandle(HttpServletRequest request, HttpServletResponse response, Object handler, ModelAndView modelAndView) throws Exception {
System.out.println("postHandle...");
}
3.3 完成后处理
//原始方法调用完成后执行的内容
public void afterCompletion(HttpServletRequest request, HttpServletResponse response, Object handler, Exception ex) throws Exception {
System.out.println("afterCompletion...");
}
- 参数
ex:如果处理器执行过程中出现异常对象,可以针对异常情况进行单独处理