SkyWalking自定义链路追踪实现步骤

<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0"
         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
    <parent>
        <artifactId>vnacos</artifactId>
        <groupId>com.nacos</groupId>
        <version>0.0.1-SNAPSHOT</version>
    </parent>
    <modelVersion>4.0.0</modelVersion>
    <artifactId>order</artifactId>
    <properties>
        <maven.compiler.source>8</maven.compiler.source>
        <maven.compiler.target>8</maven.compiler.target>
        <!-- ali 连接池 -->
        <druid.version>1.1.9</druid.version>
        <java.version>1.8</java.version>
        <!-- mybatis -->
        <mybatis-plus-boot-starter.version>3.0-RELEASE</mybatis-plus-boot-starter.version>
        <mybatis-spring-boot-starter.version>1.3.2</mybatis-spring-boot-starter.version>
        <mybatis.ehcache.version>1.1.0</mybatis.ehcache.version>
    </properties>
    <dependencies>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
        </dependency>
        <!-- ali 连接池依赖 -->
        <dependency>
            <groupId>com.alibaba</groupId>
            <artifactId>druid-spring-boot-starter</artifactId>
            <version>${druid.version}</version>
        </dependency>
        <!-- mybatis 依赖 -->
        <dependency>
            <groupId>org.mybatis.spring.boot</groupId>
            <artifactId>mybatis-spring-boot-starter</artifactId>
            <version>${mybatis-spring-boot-starter.version}</version>
        </dependency>
        <dependency>
            <groupId>com.baomidou</groupId>
            <artifactId>mybatis-plus-boot-starter</artifactId>
            <version>${mybatis-plus-boot-starter.version}</version>
        </dependency>
        <dependency>
            <groupId>org.mybatis.caches</groupId>
            <artifactId>mybatis-ehcache</artifactId>
            <version>${mybatis.ehcache.version}</version>
        </dependency>
        <!-- mysql 依赖 -->
        <dependency>
            <groupId>mysql</groupId>
            <artifactId>mysql-connector-java</artifactId>
        </dependency>
        <!--nacos-服务注册发现-->
        <dependency>
            <groupId>com.alibaba.cloud</groupId>
            <artifactId>spring-cloud-starter-alibaba-nacos-discovery</artifactId>
        </dependency>
      <strong>  <!-- SkyWalking 工具类， 跟服务版本一致 -->
        <dependency>
            <groupId>org.apache.skywalking</groupId>
            <artifactId>apm-toolkit-trace</artifactId>
            <version>8.5.0</version>
        </dependency></strong>
    </dependencies>
    <!--
    项目打包时会将java目录中的*.xml文件也进行打包
    此处必须添加项目打包，不然会报错：Invalid bound statement (not found): XXXXXXX
 -->
    <build>
        <resources>
            <resource>
                <directory>src/main/java</directory>
                <includes>
                    <include>**/*.xml</include>
                </includes>
                <filtering>false</filtering>
            </resource>
        </resources>
    </build>
</project>

package com.order.service.Impl;
import com.baomidou.mybatisplus.extension.service.impl.ServiceImpl;
import com.order.entity.Emp;
import com.order.mapper.EmpMapper;
import com.order.service.EmpService;
import org.apache.skywalking.apm.toolkit.trace.Tag;
import org.apache.skywalking.apm.toolkit.trace.Tags;
import org.apache.skywalking.apm.toolkit.trace.Trace;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;
import java.util.List;
/**
 * @author vn
 * @version 1.0
 * @date 2022/3/17 20:53
 */
@Service
public class EmpServiceImpl extends ServiceImpl<EmpMapper,Emp> implements EmpService {
    @Autowired
    private EmpMapper empMapper;
    @Override
   <strong> @Trace
    @Tags({@Tag(key</strong><strong>="selectEmpById",value="returnedObj"),
            @Tag(key="selectEmpById",value="arg[0]")})
    </strong>public Emp selectEmpById(Integer id) {
        return empMapper.selectEmpById(id);
    }
    @Override
  <strong>  @Trace
    @Tag(key</strong><strong>="selectEmp",value="returnedObj")
    </strong>public List<Emp> selectEmp() {
        return empMapper.selectEmp();
    }
}

@Trace将方法加入追踪链路 
如果一个业务方法想在ui界面的跟踪链路上显示出来，只需要在业务方法上加上@Trace注解即可
@Tags或@Tag 我们还可以为追踪链路增加其他额外的信息，比如记录参数和返回信息。实现方式：在方法上增加@Tag或者@Tag； @Tag 注解中 key = 方法名 ； value = returnedObj 返回值 arg[0] 参数