一:过滤器
1.过滤器介绍
过滤器是处于客户端与服务器资源文件之间的一道过滤网,帮助我们过滤一些不符合要求的请求。通常用作 Session校验,判断用户权限。
2.过滤器生命周期
使用过滤器很简单,只需要实现Filter类,然后重写它的3个方法即可。
- init方法:程序启动调用Filter的init()方法(永远只调用一次);在容器中创建当前过滤器的时候自动调用这个方法。
- destory方法:程序停止调用Filter的destroy()方法(永远只调用一次);在容器中销毁当前过滤器的时候自动调用这个方法。
- doFilter方法:doFilter()方法每次的访问请求如果符合拦截条件都会调用(程序第一次运行,会在servlet调用init()方法以后调用;不管第几次,都在调用doGet(),doPost()方法之前)。这个方法有3个参数,分别是ServletRequest、ServletResponse和FilterChain可以从参数中获取HttpServletReguest和HttpServletResponse对象进行相应的处理操作。
二:使用注解方式实现过滤器(@WebFilter)
1.在springboot 启动类添加该注解@ServletComponentScan
@SpringBootApplication
@ServletComponentScan // 过滤器
public class Springboot02WebTestApplication {
SpringApplication.run(Springboot02WebTestApplication.class, args);
}
2.写个过滤器类,实现Filter接口
import com.alibaba.fastjson.JSONObject;
import org.springframework.core.annotation.Order;
import javax.servlet.*;
import javax.servlet.annotation.WebFilter;
import javax.servlet.http.HttpServletRequest;
import java.io.IOException;
import java.io.PrintWriter;
// urlPatterns 过滤路径 filterName 过滤器name
@WebFilter(urlPatterns = "/user/*", filterName = "tokenFilter1")
public class TokenFilter1 implements Filter {
@Override
public void init(FilterConfig filterConfig) throws ServletException {
// Filter.super.init(filterConfig);
System.out.println("init");
}
@Override
public void doFilter(ServletRequest servletRequest, ServletResponse servletResponse, FilterChain filterChain) throws IOException, ServletException {
System.out.println("doFilter");
HttpServletRequest request = (HttpServletRequest) servletRequest;
String token = request.getHeader("token");
System.out.println(token);
//该方法执行后直接运行至下一个过滤器
if(token!=null){
filterChain.doFilter(servletRequest, servletResponse);
}else{
servletResponse.setCharacterEncoding("UTF-8");
servletResponse.setContentType("application/json; charset=utf-8");
PrintWriter out = servletResponse.getWriter();
JSONObject res = new JSONObject();
res.put("msg", "错误");
res.put("success", "false");
out.append(res.toString());
}
}
@Override
public void destroy() {
// Filter.super.destroy();
System.out.println("destroy");
}
}
3.访问,我使用的Postman软件进行的测试
添加请求头token信息,才可以访问成功。文章来源:https://www.toymoban.com/news/detail-618161.html
三:使用非注解方式实现过滤器(直接注入到spring中)
1.Filter代码
import com.alibaba.fastjson.JSONObject;
import javax.servlet.*;
import javax.servlet.http.HttpServletRequest;
import java.io.IOException;
import java.io.PrintWriter;
public class TokenFilter2 implements Filter {
@Override
public void init(FilterConfig filterConfig) throws ServletException {
System.out.println("init");
}
@Override
public void doFilter(ServletRequest servletRequest, ServletResponse servletResponse, FilterChain filterChain) throws IOException, ServletException {
System.out.println("doFilter");
HttpServletRequest request = (HttpServletRequest) servletRequest;
String token = request.getHeader("token");
System.out.println(token);
//该方法执行后直接运行至下一个过滤器
if(token!=null){
filterChain.doFilter(servletRequest, servletResponse);
}else{
servletResponse.setCharacterEncoding("UTF-8");
servletResponse.setContentType("application/json; charset=utf-8");
PrintWriter out = servletResponse.getWriter();
JSONObject res = new JSONObject();
res.put("msg", "错误");
res.put("success", "false");
out.append(res.toString());
}
}
@Override
public void destroy() {
System.out.println("destroy");
}
}
2.Filter配置文件
import com.itsufu.filter.TokenFilter2;
import org.springframework.boot.web.servlet.FilterRegistrationBean;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
@Configuration
public class FilterConfig {
// Filter代码类
@Bean
public TokenFilter2 tokenFilter2() {
return new TokenFilter2();
}
@Bean
public FilterRegistrationBean getFilterRegistrationBean(TokenFilter2 tokenFilter2) {
FilterRegistrationBean filterRegistrationBean = new FilterRegistrationBean();
filterRegistrationBean.setFilter(tokenFilter2);
filterRegistrationBean.setOrder(2);
filterRegistrationBean.addUrlPatterns("/user/*");
filterRegistrationBean.setName("tokenFilter2");
return filterRegistrationBean;
}
}
3.测试与注解式一样。
在此,祝各位帅哥美女,步步高升,一帆风顺!!!文章来源地址https://www.toymoban.com/news/detail-618161.html
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