How do I inject a logger into a field in the sample spring boot application?

Question

What I want is to make spring autowire a logger. So, in other words, I want to have this working:

import javax.servlet.http.HttpServletResponse;

import org.slf4j.Logger;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.RequestMapping;

@Controller
public class MainController {

    @Autowired
    private Logger logger;

    @RequestMapping("/")
    public String enterSite(HttpServletResponse response) {
        logger.info("site entered");
        return "welcome";
    }
}

Right now it throws an exception at startup: "No qualifying bean of type [org.slf4j.Logger] found for dependency...".

My pom.xml dependencies:

<parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>1.2.0.M1</version>
        <relativePath /> <!-- lookup parent from repository -->
    </parent>

    <dependencies>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-data-jpa</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-data-rest</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-actuator</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-test</artifactId>
            <scope>test</scope>
        </dependency>
        <dependency>
            <groupId>org.apache.tomcat.embed</groupId>
            <artifactId>tomcat-embed-jasper</artifactId>
            <scope>provided</scope>
        </dependency>
        <dependency>
            <groupId>javax.servlet</groupId>
            <artifactId>jstl</artifactId>
        </dependency>

        <dependency>
            <groupId>postgresql</groupId>
            <artifactId>postgresql</artifactId>
            <version>9.1-901.jdbc4</version>
        </dependency>
        <!-- <dependency> <groupId>mysql</groupId> <artifactId>mysql-connector-java</artifactId> 
            </dependency> -->
    </dependencies>

I read this

http://docs.spring.io/spring-boot/docs/current/reference/htmlsingle/#boot-features-logging

It says if you use one of the starter poms (i do) Logback is used - but for internal logging. Can it be autowired in my classes?

Answer 1

If the objective here is code reduction then try Project Lombok. You then don't even need to declare the logger - just add an annotation and use log instead of logger

So your above code will now look like this:

import javax.servlet.http.HttpServletResponse;

import org.slf4j.Logger;
// import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.RequestMapping;

import lombok.extern.slf4j.Slf4j;

@Slf4j
@Controller
public class MainController {

    @RequestMapping("/")
    public String enterSite(HttpServletResponse response) {
        log.info("site entered");
        return "welcome";
    }
}