如何在 Spring Boot 中设置过滤器链？

Posted 2023-02-26

【中文标题】如何在 Spring Boot 中设置过滤器链？

【英文标题】：How to set up filter chain in spring boot?

【发布时间】：2016-11-09 15:34:11

【问题描述】：

我遇到过spring-boot，打算为传入的请求添加一个过滤器链。

这是应用程序：

package example.hello;

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.context.ApplicationContext;

@SpringBootApplication
public class Application 

    public static void main(String[] args) 
        ApplicationContext ctx = SpringApplication.run(Application.class, args);
    

这里是控制器：

package example.hello;

import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestParam;
import org.springframework.web.bind.annotation.RestController;

import java.util.concurrent.atomic.AtomicLong;

@RestController
public class GreetingController 

    private static final String template = "Hello, %s!";
    private final AtomicLong counter = new AtomicLong();

    @RequestMapping("/greeting")
    public Greeting greeting(@RequestParam(value="name", defaultValue="World") String name) 
        return new Greeting(counter.incrementAndGet(),
                String.format(template, name));
    

这是过滤器配置：

package example.hello;

import org.springframework.boot.context.embedded.FilterRegistrationBean;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;

@Configuration
public class WebConfig 

    @Bean
    public FilterRegistrationBean greetingFilterRegistrationBean() 
        FilterRegistrationBean registrationBean = new FilterRegistrationBean();
        registrationBean.setName("greeting");
        GreetingFilter greetingFilter = new GreetingFilter();
        registrationBean.setFilter(greetingFilter);
        registrationBean.setOrder(1);
        return registrationBean;
    

    @Bean
    public FilterRegistrationBean helloFilterRegistrationBean() 
        FilterRegistrationBean registrationBean = new FilterRegistrationBean();
        registrationBean.setName("hello");
        HelloFilter helloFilter = new HelloFilter();
        registrationBean.setFilter(helloFilter);
        registrationBean.setOrder(2);
        return registrationBean;
    

这里是 HelloFilter 和 Greeting Filter：

package example.hello;

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

public class HelloFilter implements Filter 
    @Override
    public void init(FilterConfig filterConfig) throws ServletException 

    

    @Override
    public void doFilter(ServletRequest servletRequest, ServletResponse servletResponse, FilterChain filterChain) throws IOException, ServletException 
        System.out.println("HelloFilter!");
    

    @Override
    public void destroy() 

    


package example.hello;

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

public class GreetingFilter implements Filter 
    @Override
    public void init(FilterConfig filterConfig) throws ServletException 

    

    @Override
    public void doFilter(ServletRequest servletRequest, ServletResponse servletResponse, FilterChain filterChain) throws IOException, ServletException 
        System.out.println("Greetings from filter!");
    

    @Override
    public void destroy() 

    

当我启动应用程序并运行curl localhost:8080/greeting 时，只收到“来自过滤器的问候”并且不会调用HelloFilter。

此外，Greeting Controller 没有任何回应。似乎GreetingFilter 阻止了该过程。

那么如何在 Spring boot 中设置过滤器链。上面的代码有bug吗？

【问题讨论】：

您的代码有缺陷...您在第一个过滤器处停止/阻止请求，它永远不会通过。您需要拨打filterChain.doFilter(request, response) 继续通话...

【参考方案1】：

在 GreetingFilter 中添加以下代码行

filterChain.doFilter(servletRequest, servletResponse);

【参考方案2】：

我想进一步澄清一下 Gangadhar 的建议。您可以尝试添加：

filterChain.doFilter(servletRequest, servletResponse);

在过滤器类的 doFilter 方法中。这将创建过滤器的链接。