java中过滤器和拦截器的区别
区别
1.使用范围和规范不同
- filter是servlet规范规定的,只能用在web程序中.
- 拦截器即可以用在web程序中, 也可以用于application, swing程序中, 是Spring容器内的, 是Spring框架支持的
2.触发时机不同
顺序: Filter-->Servlet-->Interceptor-->Controller
- 过滤器是在请求进入容器后，但请求进入servlet之前进行预处理的。请求结束返回也是，是在servlet处理完后，返回给前端之前过滤器处理。
- 拦截器是方法到达Controller层之前生效的
3.过滤器的实现基于回调函数。而拦截器（代理模式）的实现基于反射，代理分静态代理和动态代理，动态代理是拦截器的简单实现。
何时使用拦截器？何时使用过滤器？
- 如果是非spring项目，那么拦截器不能用，只能使用过滤器。
- 如果是处理controller前后，既可以使用拦截器也可以使用过滤器。
- 如果是处理dispaterServlet前后，只能使用过滤器。
4.在action的生命周期中，拦截器可以多次被调用，而过滤器只能在容器初始化时被调用一次。
5.拦截器可以访问action上下文、值栈里的对象，而过滤器不能访问。
6.拦截器只能对action请求起作用，而过滤器则可以对几乎所有的请求起作用。
7.拦截器可以获取IOC容器中的各个bean，而过滤器就不行，在拦截器里注入一个service，可以调用业务逻辑。
SpringBoot使用过滤器
两种方式：
1、使用spring boot提供的FilterRegistrationBean注册Filter
2、使用原生servlet注解定义Filter
两种方式的本质都是一样的，都是去FilterRegistrationBean注册自定义Filter
封装Filter
package com.theeternity.common.baseFilter;
import javax.servlet.Filter;
/**
* @program: ApiBoot
* @description: 封装Filter
* @author: TheEternity Zhang
* @create: 2019-02-17 13:08
*/
public interface MappingFilter extends Filter {
String[] addUrlPatterns();
int order();
}
自定义Filter
package com.theeternity.beans.filterConfig;
import com.theeternity.common.baseFilter.MappingFilter;
import lombok.extern.slf4j.Slf4j;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import javax.servlet.*;
import javax.servlet.FilterConfig;
import java.io.IOException;
/**
* @program: ApiBoot
* @description: 权限过滤器
* @author: TheEternity Zhang
* @create: 2019-02-17 13:14
*/
public class AuthFilter implements MappingFilter {
@Override
public String[] addUrlPatterns() {
return new String[]{"/*"};
}
@Override
public int order() {
return 0;
}
@Override
public void init(FilterConfig filterConfig) throws ServletException {
}
@Override
public void doFilter(ServletRequest servletRequest, ServletResponse servletResponse, FilterChain filterChain) throws IOException, ServletException {
filterChain.doFilter(servletRequest,servletResponse);
}
@Override
public void destroy() {
}
}
注册过滤器
package com.theeternity.beans.filterConfig;
import org.springframework.boot.web.servlet.FilterRegistrationBean;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
/**
* @program: ApiBoot
* @description: 注册过滤器
* @author: TheEternity Zhang
* @create: 2019-02-17 13:10
*/
@Configuration
public class FilterConfig {
@Bean
public FilterRegistrationBean registFilter() {
FilterRegistrationBean registration = new FilterRegistrationBean();
AuthFilter authFilter=new AuthFilter();
registration.setFilter(authFilter);
registration.addUrlPatterns(authFilter.addUrlPatterns());
registration.setOrder(authFilter.order());
registration.setName("AuthFilter");
return registration;
}
}
SpringBoot使用拦截器
封装Interceptor
package com.theeternity.common.baseInterceptor;
import org.springframework.web.servlet.HandlerInterceptor;
/**
* @program: ApiBoot
* @description: 封装Interceptor
* @author: TheEternity Zhang
* @create: 2019-02-15 17:49
*/
public interface MappingInterceptor extends HandlerInterceptor {
String[] addPathPatterns();
String[] excludePathPatterns();
int order();
}
自定义Interceptor
package com.theeternity.beans.interceptorConfig;
import com.theeternity.common.baseInterceptor.MappingInterceptor;
import org.springframework.stereotype.Component;
import org.springframework.web.servlet.ModelAndView;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
/**
* @program: BoxApi
* @description: 跨域拦截器
* @author: tonyzhang
* @create: 2018-12-21 14:44
*/
@Component
public class CrossOriginInterceptor implements MappingInterceptor {
@Override
public String[] addPathPatterns() {
return new String[]{"/**"};
}
@Override
public String[] excludePathPatterns() {
return new String[0];
}
@Override
public int order() {
return 0;
}
@Override
public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler) throws Exception {
logger.info("允许的头信息"+request.getHeader("Origin"));
response.setHeader("Access-Control-Allow-Origin", "*");
response.setHeader("Access-Control-Allow-Methods", "*");
response.setHeader("Access-Control-Max-Age", "3600");
response.setHeader("Access-Control-Allow-Headers", "Origin, X-Requested-With, Content-Type, Accept");
//是否允许浏览器携带用户身份信息（cookie）
response.setHeader("Access-Control-Allow-Credentials","true");
return true;
}
@Override
public void postHandle(HttpServletRequest request, HttpServletResponse response, Object handler, ModelAndView modelAndView) throws Exception {
}
@Override
public void afterCompletion(HttpServletRequest request, HttpServletResponse response, Object handler,Exception ex) throws Exception {
}
}
注册Interceptor
package com.theeternity.beans.interceptorConfig;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.context.annotation.Configuration;
import org.springframework.web.servlet.config.annotation.InterceptorRegistry;
import org.springframework.web.servlet.config.annotation.WebMvcConfigurer;
/**
* @program: ApiBoot
* @description: 拦截器注册
* @author: TheEternity Zhang
* @create: 2019-02-15 17:55
*/
@Configuration
public class InterceptorConfig implements WebMvcConfigurer {
@Autowired
private CrossOriginInterceptor crossOriginInterceptor;
@Override
public void addInterceptors(InterceptorRegistry registry) {
registry.addInterceptor(crossOriginInterceptor).addPathPatterns(crossOriginInterceptor.addPathPatterns());
}
}
站在巨人的肩膀上摘苹果:
https://blog.csdn.net/heweimingming/article/details/79993591
