SpringCloud 集成spring-boot-starter-log4j2

要在 Spring Cloud 中集成 Log4j2 日志框架，可以通过添加以下依赖项来实现：

<dependency>
    <groupId>org.springframework.cloud</groupId>
    <artifactId>spring-cloud-starter-sleuth</artifactId>
</dependency>
<dependency>
    <groupId>org.springframework.cloud</groupId>
    <artifactId>spring-cloud-sleuth-zipkin</artifactId>
</dependency>
<dependency>
    <groupId>org.springframework.cloud</groupId>
    <artifactId>spring-cloud-sleuth-stream</artifactId>
</dependency>
<dependency>
    <groupId>org.springframework.cloud</groupId>
    <artifactId>spring-cloud-starter-zipkin</artifactId>
</dependency>
<dependency>
    <groupId>org.springframework.cloud</groupId>
    <artifactId>spring-cloud-starter-config</artifactId>
</dependency>
<dependency>
    <groupId>org.springframework.cloud</groupId>
    <artifactId>spring-cloud-starter-bus-amqp</artifactId>
</dependency>
<dependency>
    <groupId>org.springframework.cloud</groupId>
    <artifactId>spring-cloud-starter-stream-rabbit</artifactId>
</dependency>
<dependency>
    <groupId>org.springframework.cloud</groupId>
    <artifactId>spring-cloud-stream-binder-rabbit</artifactId>
</dependency>
<dependency>
    <groupId>org.apache.logging.log4j</groupId>
    <artifactId>log4j-slf4j-impl</artifactId>
    <version>${log4j.version}</version>
</dependency>

然后在 `application.properties` 文件中添加以下配置：

spring.cloud.stream.bindings.output.destination=myTopic
spring.sleuth.sampler.probability=1.0
logging.level.org.springframework.cloud.stream=DEBUG
logging.level.org.springframework.integration=DEBUG
logging.level.org.springframework.amqp=DEBUG
spring.cloud.stream.bindings.input.destination=myTopic
spring.rabbitmq.host=localhost
spring.rabbitmq.port=5672
spring.rabbitmq.username=guest
spring.rabbitmq.password=guest
spring.zipkin.baseUrl=http://localhost:9411

这里的配置包括了日志的级别以及 Sleuth 和 Zipkin 的配置。最后，可以使用以下代码来测试日志输出：

@Slf4j
@RestController
@RequestMapping("/api")
public class DemoController {

    @GetMapping("/test")
    public String test() {
        log.debug("This is a debug message");
        log.info("This is an info message");
        log.warn("This is a warning message");
        log.error("This is an error message");
        return "Test";
    }
}

如果一切顺利，你应该能够在控制台看到输出的日志信息。