那么在springBoot中如何使用过滤器呢？
一般是使用Component和WebFilter 这两个注解，但是这里我们就直接方法调用。
在该方法中添加Bean注解，springBoot会在启动的时候进行调用。并指定需要过滤的请求。
代码示例:
@Bean
public FilterRegistrationBean testFilterRegistration() {
FilterRegistrationBean registration = new FilterRegistrationBean();
registration.setFilter(new MyFilter());
//过滤掉 /getUser 和/hello 的请求
registration.addUrlPatterns("/getUser","/hello");
//过滤掉所有请求
//
registration.addUrlPatterns("/*");
registration.setName("MyFilter");
registration.setOrder(1);
return registration;
}
说明: registration.setOrder() 方法是设置优先级，数值越大，优先级越高。
拦截器
拦截器是什么?
简单的来说，就是一道阀门，拦截不需要的东西。
拦截器主要做什么？
对正在运行的流程进行干预。
拦截器的代码实现。
拦截器也主要有三个方法，其中preHandle是在请求之前就进行调用，如果该请求需要被拦截，则返回false，否则true; postHandle是在请求之后进行调用，无返回值;afterCompletion是在请求结束的时候进行调用，无返回值。
这里我们就简单的模拟下拦截非白名单的IP请求。
代码示例:
class MyInterceptor implements HandlerInterceptor {
@Autowired
private IpConfig ipconfig;
public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object arg2) throws Exception {
String ip = getIpAddr(request);
// 获取可以访问系统的白名单
String ipStr = ipconfig.getIpWhiteList();
String[] ipArr = ipStr.split("\\|");
List<String> ipList = Arrays.asList(ipArr);
if (ipList.contains(ip)) {
System.out.println("该IP: " + ip+"通过!");
return true;
} else {
System.out.println("该IP: " + ip+"不通过!");
response.setCharacterEncoding("UTF-8");
response.setContentType("application/json; charset=utf-8");
// 消息
Map<String, Object> messageMap = new HashMap<>();
messageMap.put("status", "1");
messageMap.put("message", "您好，ip为" + ip + ",暂时没有访问权限，请联系管理员开通访问权限。");
ObjectMapper objectMapper=new ObjectMapper();
String writeValueAsString = objectMapper.writeValueAsString(messageMap);
response.getWriter().write(writeValueAsString);
return false;
}
}
public String getIpAddr(HttpServletRequest request) {
String ip = request.getHeader("X-Forwarded-For");
if (ip == null || ip.length() == 0 || "unknown".equalsIgnoreCase(ip)) {
ip = request.getHeader("Proxy-Client-IP");
}
if (ip == null || ip.length() == 0 || "unknown".equalsIgnoreCase(ip)) {
ip = request.getHeader("WL-Proxy-Client-IP");
}
if (ip == null || ip.length() == 0 || "unknown".equalsIgnoreCase(ip)) {
ip = request.getHeader("HTTP_CLIENT_IP");
}
if (ip == null || ip.length() == 0 || "unknown".equalsIgnoreCase(ip)) {
ip = request.getHeader("HTTP_X_FORWARDED_FOR");
}
if (ip == null || ip.length() == 0 || "unknown".equalsIgnoreCase(ip)) {
ip = request.getRemoteAddr();
}
return ip;
}
@Override
public void postHandle(HttpServletRequest httpServletRequest, HttpServletResponse httpServletResponse, Object o, ModelAndView modelAndView) throws Exception {
System.out.println("postHandle被调用");
}
@Override
public void afterCompletion(HttpServletRequest httpServletRequest, HttpServletResponse httpServletResponse, Object o, Exception e) throws Exception {
System.out.println("afterCompletion被调用");
}
}
依旧再启动springBoot的时候启动拦截器，并指定拦截的请求。
代码示例:
import
java.util.Arrays;
import
java.util.HashMap;
import java.util.List;
import java.util.Map;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.web.servlet.HandlerInterceptor;
import org.springframework.web.servlet.ModelAndView;
import org.springframework.web.servlet.config.annotation.InterceptorRegistry;
import org.springframework.web.servlet.config.annotation.WebMvcConfigurerAdapter;
import com.fasterxml.jackson.databind.ObjectMapper;
import com.pancm.springboot_config.config.IpConfig;
@Configuration
public class MyWebAppConfigurer extends WebMvcConfigurerAdapter {
@Bean
public HandlerInterceptor getMyInterceptor(){
return new MyInterceptor();
}
@Override
public void addInterceptors(InterceptorRegistry registry) {
// addPathPatterns 用于添加拦截规则, 这里假设拦截 /url 后面的全部链接
// excludePathPatterns 用户排除拦截
registry.addInterceptor(getMyInterceptor()).addPathPatterns("/**");
super.addInterceptors(registry);
}
}
结语
