springboot使用filter增加全局traceId，方便日志查找

一：引入依赖

        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
        </dependency>

二：编写过滤器：

package com.example.demo.filter;
 
import org.slf4j.MDC;
import org.springframework.util.StringUtils;
 
import javax.servlet.*;
import javax.servlet.http.HttpServletRequest;
import java.io.IOException;
import java.util.UUID;
 
public class FilterGobalTraceId implements Filter {
    @Override
    public void init(FilterConfig filterConfig) throws ServletException {
        // 初始化操作
    }
 
    @Override
    public void doFilter(ServletRequest request, ServletResponse response, FilterChain chain)
            throws IOException, ServletException {
        try {
            HttpServletRequest httpRequest = (HttpServletRequest) request;
            String oldTraceId = httpRequest.getHeader("traceId");
 
            if(!StringUtils.isEmpty(oldTraceId)){
                MDC.put("traceId",oldTraceId);
            }else {
                // 生成唯一的traceId
                MDC.put("traceId", generateTraceId());
            }
            chain.doFilter(request, response);
        } finally {
            // 清除MDC的traceId值，确保在请求结束后不会影响其他请求的日志
            MDC.remove("traceId");
        }
    }
 
    @Override
    public void destroy() {
        // 清理操作
    }
 
    private String generateTraceId() {
        // 在此处生成唯一的traceId，并返回
        return UUID.randomUUID().toString();
    }
}

三：配置过滤器注册ben,并把过滤器注册

package com.example.demo.filter;
 
import org.springframework.boot.web.servlet.FilterRegistrationBean;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
 
@Configuration
public class GobalWebTraceIdConfig {
    @Bean
    public FilterRegistrationBean loggingFilter() {
        FilterRegistrationBean registrationBean = new FilterRegistrationBean<>();
        registrationBean.setFilter(new FilterGobalTraceId());
        registrationBean.addUrlPatterns("/*"); // 设置过滤的URL模式
        return registrationBean;
    }
}