springboot整合拦截器、过滤器、解决跨域问题。

企业开发 2024-11-06 19:07:38 阅读次数: 0

1、首先，创建一个自定义的拦截器类，实现HandlerInterceptor接口，代码如下：

import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import org.springframework.stereotype.Component;
import org.springframework.web.servlet.HandlerInterceptor;
import org.springframework.web.servlet.ModelAndView;

@Component
public class CustomInterceptor implements HandlerInterceptor {
    
    
    
    @Override
    public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler) throws Exception {
    
    
        System.out.println("请求拦截器 - 在请求处理之前调用");
        return true; // 返回 true 表示允许请求继续进行
    }
    
    @Override
    public void postHandle(HttpServletRequest request, HttpServletResponse response, Object handler, ModelAndView modelAndView) throws Exception {
    
    
        System.out.println("请求拦截器 - 在请求处理之后调用，但在视图被渲染之前");
    }
    
    @Override
    public void afterCompletion(HttpServletRequest request, HttpServletResponse response, Object handler, Exception ex) throws Exception {
    
    
        System.out.println("请求拦截器 - 在请求处理完成后调用");
    }
}

2、在应用程序的配置类中注册拦截器，代码如下：

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;

@Configuration
public class AppConfig implements WebMvcConfigurer {
    
    

    private final CustomInterceptor customInterceptor;

    @Autowired
    public AppConfig(CustomInterceptor customInterceptor) {
    
    
        this.customInterceptor = customInterceptor;
    }

    @Override
    public void addInterceptors(InterceptorRegistry registry) {
    
    
        registry.addInterceptor(customInterceptor);
    }
}

3、创建一个自定义的过滤器类，实现javax.servlet.Filter接口，代码如下：

import javax.servlet.*;
import javax.servlet.annotation.WebFilter;
import java.io.IOException;

@WebFilter(urlPatterns = "/*")
public class CustomFilter implements Filter {
    
    
    
    @Override
    public void init(FilterConfig filterConfig) throws ServletException {
    
    
        System.out.println("过滤器 - 初始化");
    }
    
    @Override
    public void doFilter(ServletRequest request, ServletResponse response, FilterChain chain) throws IOException, ServletException {
    
    
        System.out.println("过滤器 - 请求处理之前");
        chain.doFilter(request, response); // 继续请求处理
        System.out.println("过滤器 - 请求处理之后");
    }
    
    @Override
    public void destroy() {
    
    
        System.out.println("过滤器 - 销毁");
    }
}

4、在应用程序的主类上添加@ServletComponentScan注解，以便自动扫描过滤器：

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.boot.web.servlet.ServletComponentScan;

@SpringBootApplication
@ServletComponentScan
public class Application {
    
    

    public static void main(String[] args) {
    
    
        SpringApplication.run(Application.class, args);
    }
}

5、对于跨域请求，可以通过配置CorsFilter来处理。代码如下：

import org.springframework.web.filter.CorsFilter;
import org.springframework.web.cors.CorsConfiguration;
import org.springframework.web.cors.UrlBasedCorsConfigurationSource;

@Configuration
public class CorsConfig {
    
    

    @Bean
    public CorsFilter corsFilter() {
    
    
        UrlBasedCorsConfigurationSource source = new UrlBasedCorsConfigurationSource();
        CorsConfiguration config = new CorsConfiguration();
        config.addAllowedOrigin("*"); // 允许所有来源
        config.addAllowedMethod("*"); // 允许所有HTTP方法
        config.addAllowedHeader("*"); // 允许所有请求头
        source.registerCorsConfiguration("/**", config); // 对所有路径生效
        return new CorsFilter(source);
    }
}